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Impacts of Climate Related Geo-engineering on Biological Diversity
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Study carried out in line with CBD Decision X/33
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Draft Reviewed – 23 January 2012
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Not for Citation or Circulation
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This is a draft report for a second round of review. The draft report compiles and
synthesizes available scientific information on the possible impacts of geo-engineering
techniques on biodiversity, including preliminary information on associated social, economic
and cultural considerations. The report also considers definitions and understandings of
climate-related geo-engineering relevant to the Convention on Biological Diversity (CBD).
The report is being prepared in response to CBD Decision X/33, paragraph 9(l). The final
report will take into account the additional review comments.
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EXECUTIVE SUMMARY / KEY MESSAGES
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Biodiversity, ecosystems and their services are critical to human well being. Protection
of biodiversity and ecosystems requires that drivers of biodiversity loss are reduced.
The main direct drivers of biodiversity loss are habitat conversion, over-exploitation, the
introduction of invasive species, pollution and climate change. These in turn are being driven
by demographic, economic, technological, socio-political and cultural changes. Climate
change is becoming increasingly important as a driver of the biodiversity loss and the
degradation of ecosystem services. It is best addressed by a rapid and significant reduction in
greenhouse gas emissions through a transition to a low-carbon economy. However, given the
insufficient action to date to reduce greenhouse gas emissions, the use of geo-engineering
techniques has been suggested to limit the magnitude of human-induced climate change and
or its impacts.
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Proposed climate-related geo-engineering techniques
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In this report, climate-related geo-engineering is defined as a deliberate intervention in
the planetary environment of a nature and scale intended to counteract anthropogenic
climate change and/or its impacts through, inter alia, solar radiation management or
removing greenhouse gases from the atmosphere.1 There is a range of alternative definitions
and understandings of the term (Section 2.1).
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Solar radiation management (SRM) techniques aim to counteract warming by reducing
the incidence and subsequent absorption of incoming solar radiation but would not treat
the root cause of anthropogenic climate change arising from greenhouse gas
concentrations in the atmosphere. They would rapidly have an effect once deployed at the
appropriate scale, and thus are the only proposed approach that might allow a rapid reduction in
temperatures should it be deemed necessary. SRM techniques would not address ocean
acidification. They would introduce a new dynamic between the warming effects of
greenhouse gases and the cooling effects of SRM with uncertain climatic implications
especially at the regional scale. Proposed SRM techniques include:
1. Space-based approaches: reducing the amount of solar energy reaching the Earth by
positioning sun-shields in space with the aim of reflecting or deflecting solar radiation;
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This does not include carbon capture and storage from fossil fuels when carbon dioxide is captured before it is
released into the atmosphere.
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References in parentheses indicate where full information can be found in the main report.
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2. Changes in stratospheric aerosols: injecting sulphates or other types of particles into
the upper atmosphere, with the aim of increasing the scattering of sunlight back to space;
3. Increases in cloud reflectivity: increasing the concentration of cloud-condensation
nuclei in the lower atmosphere, thereby whitening clouds with the aim of increasing the
reflection of solar radiation;
4. Increases in surface albedo: modifying land or ocean surfaces with the aim of
reflecting more solar radiation.
Theoretically, these techniques could be implemented separately or in combination, at a range
of scales. Different techniques are at different stages of development and some are of doubtful
effectiveness. (Section 2.2.1)
Carbon dioxide removal (CDR) involves techniques aimed at removing CO2, a major
greenhouse gas, from the atmosphere, allowing outgoing long-wave (thermal infra-red)
radiation to escape more easily. In principle, other greenhouse gases (such as N 2O, and CH4),
could also be removed from the atmosphere, but such approaches have yet to be developed.
Proposed types of CDR approaches include:
1. Ocean Fertilization: the enrichment of nutrients in marine environments with the
principal intention of stimulating primary productivity in the ocean, and hence CO2 uptake
from the atmosphere, and the deposition of carbon in the deep ocean;
2. Enhanced weathering: artificially increasing the rate by which carbon dioxide is
naturally removed from the atmosphere by the weathering (dissolution) of carbonate and
silicate rocks;
3. Increasing carbon sequestration through ecosystem management: through, for
example: afforestation, reforestation or enhancing soil carbon;
4. Sequestration of carbon as biomass and its subsequent storage: through, for example,
biochar or long term storage of crop residue; and
5. Direct capture of carbon from the atmosphere and its subsequent storage, for
example, using “artificial trees” and storage in geological formations or in the deep ocean.
CDR approaches involve two steps: (1) carbon sequestration or removal of CO2 from the
atmosphere; and (2) storage of the sequestered carbon. In the first three techniques, these two
steps occur together; in the fourth and fifth, sequestration and storage may be separated in
time and space. Ecosystem-based approaches such as afforestation, reforestation or the
enhancement of soil carbon are already employed as climate change mitigation activities and
are not regarded by some as geo-engineering technologies. To have a significant impact on
the climate, CDR interventions, individually or collectively, would need to involve the
removal from the atmosphere of several Gt C/yr (gigatonnes of carbon per year), maintained
over decades and more probably centuries. It is unlikely that such approaches could be
deployed on a large enough scale to alter the climate quickly. Different techniques are at
different stages of development and some are of doubtful effectiveness. (Section 2.2.2)
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Climate change and ocean acidification, and their impacts on biodiversity
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The continued increase in atmospheric greenhouse gases has profound implications for
global and regional average temperatures, and also precipitation, ice-sheet dynamics,
sea-level rise, ocean acidification and the frequency and magnitude of extreme events.
Future climatic perturbations could be abrupt or irreversible, and potentially extend over
millennial time scales; they will inevitably have major consequences for natural and human
systems, severely affecting biodiversity and incurring very high socio-economic costs
(Section 3.1).
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Since 2000, the average rate of increase in global greenhouse gas emissions has been
~3.1% per year. As a result, it has become much more challenging to achieve the 450
ppm CO2eq target. Avoidance of high risk of dangerous climate change therefore requires an
urgent and massive effort to reduce greenhouse gas emissions. If such efforts are not made,
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geo-engineering approaches will increasingly be postulated to offset at least some of the
impacts of climate change, despite the risks and uncertainties involved (Section 3.1.2).
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Even with strong climate mitigation policies, further climate change is inevitable due to
lagged responses in the Earth climate system. Thus increases in global mean surface
temperature of 0.3 - 2.2oC are projected to occur over several centuries after atmospheric
concentrations of greenhouse gases have been stabilized, with associated increases in sea
level due to thermally-driven expansion and ice-melt. (Section 3.1.2)
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Climate change poses an increasingly severe range of threats to biodiversity and
ecosystem services, with ~10% of species estimated to be at risk of extinction for every
1⁰C rise in global mean temperature. Temperature, precipitation and other climate
attributes strongly influence the distribution and abundance of species, their interactions and
the associated functioning of ecosystems. Projected climate change is not only more rapid
than naturally-occurring climate change (e.g. during ice age cycles, that did allow relatively
gradual vegetation shifts, population movements and genetic adaptation), but the scope for
adaptive responses is now reduced by other anthropogenic pressures, including overexploitation, habitat loss, fragmentation and degradation, the introduction of non-native
species, and pollution. Extinction risk is therefore increased, since the abundance and genetic
diversity of many species are already much reduced. (Section 3.2.1)
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The terrestrial impacts of projected climate change are likely to be greatest for montane
and Arctic habitats, for coastal areas affected by sea-level change, and wherever there
are major changes in water availability. Species with limited adaptive capability will be
particularly at risk; for example, tropical fauna that are already close to their optimal
temperatures. However, insect pests and disease vectors in temperate regions are expected to
benefit. Forest ecosystems, and the goods and services they provide, are likely to be affected
as much, or more, by changes in hydrological regimes (affecting fire risk) and pest
abundance, than by direct effects of temperature change. (Section 3.2.2)
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Marine species and ecosystems are increasingly subject to ocean acidification as well as
changes in temperature. Climate driven changes in the distribution of marine organisms are
already occurring, more rapidly than on land. The loss of summer sea-ice in the Arctic will
have major biodiversity implications. Biological impacts of ocean acidification (an inevitable
chemical consequence of the increase in atmospheric CO2) are less certain; nevertheless, an
atmospheric CO2 concentration of 450 ppm would decrease surface pH change by ~0.2 units,
with the likelihood of large-scale and ecologically significant effects. Tropical corals seem to
be especially at risk, being vulnerable to the combination of ocean acidification, temperature
stress (coral bleaching), coastal pollution (eutrophication and increased sediment load) and
sea-level rise. (Section 3.2.3)
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The biosphere plays a key role in climate processes, especially as part of the carbon and
water cycles. Carbon is naturally sequestered and stored by terrestrial and marine ecosystems,
through biologically-driven processes. Proportionately small changes in ocean and terrestrial
carbon stores, caused by changes in the balance of exchange processes, can have large
implications for atmospheric CO2 levels. (Section 3.3)
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Potential impacts on biodiversity of SRM geo-engineering techniques
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SRM geo-engineering techniques, if effective in abating the magnitude of warming,
could reduce some of the climate-change related impacts on biodiversity. At the same
time, the proposed SRM techniques may have their own negative impacts on
biodiversity. Thus, if a proposed geo-engineering measures can be shown to be likely
feasible and effective in reducing the negative impacts of climate change, these projected
positive impacts need to be considered alongside any projected negative impacts of the geoengineering measure. (Chapter 4 – Introduction)
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Uniform dimming of sunlight through an unspecified generic SRM technique, to
compensate for the temperature increase from increased CO2 concentrations, would be
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expected to reduce the greenhouse-gas induced temperature change experienced by most
areas of the planet. Overall, this would be expected to reduce some of the impacts of climate
change on biodiversity, but this will vary region by region. However, only very limited
modelling work has been done and many uncertainties remain concerning the ability to realize
uniform dimming and on the side effects of SRM techniques on biodiversity. It is therefore
not possible to predict the net effect with any degree of confidence. (Section 4.1.1)
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SRM would introduce a new dynamic between the heating effects of greenhouse gases
and the cooling effects of SRM. The combination of changes – high CO2 concentrations,
unpredictably altered precipitation patterns, and in some cases more diffuse light, – would be
unlike any known combination that extant species and ecosystems have experienced in their
evolutionary history. However, it is not clear whether the environment of the SRM world
would be more or less challenging for individual species and ecosystems than that caused by
the climate change that it would be seeking to counter. (Section 4.1.3)
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SRM does not reduce atmospheric CO2 concentrations, and therefore would not reduce
ocean acidification nor its adverse affects on marine biodiversity. SRM also would not
address the effects (positive or negative) of high CO2 concentrations on terrestrial ecosystems.
Therefore, SRM is not an alternative to CO2 emission reductions. (Section 4.1.4)
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Rapid termination of SRM, that had been deployed for some time and is masking a high
degree of warming, would almost certainly have very large negative impacts on
biodiversity and ecosystem services that would be far more severe than those resulting
from gradual climate change. (Section 4.1.5)
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Stratospheric aerosol injection, using sulphate particles, would affect the overall
quantity and quality of light reaching the biosphere, have minor effects on atmospheric
acidity, and could also affect stratospheric ozone depletion, with knock-on effects on
biodiversity and ecosystem services. Stratospheric aerosols would decrease the amount of
photosynthetically active radiation (PAR) reaching the Earth, but would increase the
proportion of diffuse (as opposed to direct) radiation. This would be expected to affect
community composition and structure. It may lead to an increase of gross primary
productivity (GPP) in certain ecosystems such as forests. However, the magnitude and nature
of effects on biodiversity are likely to be mixed, and are currently not well understood. Ocean
productivity would likely decrease. Increased ozone depletion, primarily in the polar regions,
would cause an increase in the amount of ultra violet (UV) radiation reaching the Earth,
which would affect some species more than others. (Section 4.2.1)
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Cloud brightening could cause atmospheric and oceanic perturbations with possibly
significant effects on terrestrial and marine biodiversity and ecosystems. However, there
is a high degree of inconsistency among findings. Cloud brightening is expected to cause
localized cooling, the effects of which are poorly understood. (Section 4.2.2)
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If surface albedo changes were large enough to have an effect on the global climate, they
would have to be deployed across a very large area – with consequent impacts on
ecosystems – or would involve a very high degree of localized cooling. For instance,
covering deserts with reflective material on a scale large enough to be effective in addressing
the impacts of climate change would have significant negative effects on biodiversity, for
instance on species richness and population densities, as well as on the customary use of
biodiversity. (Section 4.2.3)
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Potential impacts on biodiversity of CDR geo-engineering techniques
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CDR techniques, if effective and feasible, would be expected to reduce the negative
impacts on biodiversity of climate change and, in some cases, of ocean acidification. By
removing carbon dioxide (CO2) from the atmosphere, CDR techniques reduce the
concentration of the main causal agent of anthropogenic climate change. Depending on the
technique employed, ocean acidification may be reduced as well. They are generally slow in
affecting the atmospheric CO2 concentration and there are further substantial time–lags in the
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climatic benefits. Several of the techniques are of doubtful effectiveness. In addition, the
positive effects from reduced impacts of climate change and/or ocean acidification due to
reduced atmospheric CO2 concentrations may be offset by the direct impacts on biodiversity
of the particular CDR technique employed. (Section 5.1)
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Individual CDR techniques have impacts on terrestrial and/or ocean ecosystems. In some
biologically-driven processes (ocean fertilization; afforestation, reforestation and soil carbon
enhancement), carbon sequestration or removal of CO2 from the atmosphere and storage of
the sequestered carbon occur together or are inseparable. In these cases, impacts on
biodiversity are confined to marine and terrestrial systems respectively. In other cases, the
steps are discrete, and various combinations of sequestration and storage options are possible.
Carbon sequestered as biomass, for example, could be either: dumped in the ocean as crop
residues; incorporated into the soil as charcoal; or used as fuel with the resultant CO2
sequestered at source and stored either in sub-surface reservoirs or the deep ocean. In these
cases, each step will have different and additive potential impacts on biodiversity, and
potentially separate impacts on marine and terrestrial environments. (Section 5.1)
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Ocean fertilization involves increased biological primary production with inevitable
changes in phytoplankton community structure and species diversity and implications
for the wider food-web. Ocean fertilization may be achieved through the external addition of
nutrients (Fe or N or P) or, possibly, by modifying ocean upwelling and downwelling. If
carried out on a climatically significant scale, changes may include an increased risk of
harmful algal blooms, and greater densities and biomass of benthos. Increases in net primary
productivity in one region will likely be offset by decreases in adjacent areas. Ocean
fertilization is expected to increase biogeochemical cycling which may be associated with
increased production of methane and nitrous oxide, significantly reducing the effectiveness of
the technique. Ocean fertilization may slow near-surface ocean acidification but would
increase acidification of the deep ocean. The limited experiments conducted to date indicate
that this is a technique of doubtful effectiveness. (Section 5.2.1)
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Enhanced weathering would involve large-scale mining and transportation of carbonate
and silicate rocks, and the spreading of solid or liquid materials on land or sea with
major impacts on terrestrial and coastal ecosystems and, in some techniques, locally
excessive alkalinity in marine systems. Carbon dioxide is naturally removed from the
atmosphere by the weathering (dissolution) of carbonate and silicate rocks. This process could
be artificially accelerated through a range of proposed techniques that include releasing
calcium carbonate or other dissolution products of alkaline minerals into the ocean or
spreading abundant silicate minerals such as olivine over agricultural soils, with potential for
negative impacts. In the ocean, this technique could contribute to countering ocean
acidification. (Section 5.2.2)
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The impacts on biodiversity of ecosystem carbon storage through afforestation,
reforestation, or the enhancement of soil carbon depend on the method and scale of
implementation. If managed well, this approach has the potential to increase or maintain
biodiversity. Since afforestation, reforestation and land-use change are already being
promoted as climate change mitigation options, much guidance has already been developed.
For example, the CBD has developed guidance to maximize the benefits of these approaches
to biodiversity, such as the use of assemblages of native species, and to minimize the
disadvantages and risks such as the use of potentially invasive species and monocultures.
(Section 5.2.3)
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Production of biomass for carbon sequestration on a scale large enough to be
climatically significant would likely entail competition for land with food and other
crops and/or large-scale land-use change with significant impacts on biodiversity as well
as greenhouse gas emissions that may partially offset, eliminate or even exceed the
carbon sequestered as biomass. However, the coupling of biomass production with its use
as bioenergy in power stations equipped with effective carbon capture at source and storage
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has the potential to be carbon negative. The net effects on biodiversity and greenhouse gas
emissions would depend on the approaches used. The storage or disposal of biomass may
have impacts on biodiversity separate from those involved in its production. Removal of
organic matter from agricultural ecosystems is likely to have negative impacts on agricultural
productivity and biodiversity. (Section 5.2.4.1)
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The impacts of the long-term storage of charcoal in soils (“biochar”) on the structure
and function of soil itself, as well as on crop yields, mycorrhizal fungi, soil microbial
communities and detritivores, are not yet fully understood. (Section 5.2.4.2.1)
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Ocean storage of biomass (e.g. crop residues) would likely have negative impacts on
biodiversity. Deposition of ballasted bales would likely have significant local physical
impacts on the seabed due to the sheer mass of the material. Wider chemical and biological
impacts are likely. Longer-term indirect effects of oxygen depletion and deep-water
acidification could be regionally significant if there is cumulative deposition, and subsequent
decomposition, of many gigatonnes of organic carbon. (Section 5.2.4.2.2)
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Capture of carbon dioxide from ambient air through physico-chemical methods
(“artificial trees “) would require a large amount of energy and in some cases fresh
water, but otherwise would have relatively small direct impacts on biodiversity.
However, capturing CO2 from the ambient air (where its concentration is 0.04%) is much
more difficult and energy intensive than capturing CO2 from exhaust streams of power
stations (where it is about 300 times higher) and is unlikely to be viable without additional
carbon-free energy sources. CO2 that has already been extracted from the atmosphere must be
stored either in the ocean or in sub-surface geological reservoirs with additional potential
impacts. (Section 5.2.5.1)
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Ocean CO2 storage will necessarily alter the local chemical environment, with a high
likelihood of biological effects. Effects on mid-water and deep benthic fauna/ecosystems is
likely through the exposure, primarily of marine invertebrates and possibly unicellular
organisms, to pH changes of 0.1 to 0.3 units. Total destruction of deep seabed biota that
cannot flee can be expected if lakes of liquid CO2 are created. The scale of such impacts
would depend on the seabed topography, with deeper lakes of CO2 affecting less seafloor area
for a given amount of CO2. However, pH reductions would still occur in large volumes of
water near such lakes. The chronic effects on ecosystems of direct CO2 injection into the
ocean over large ocean areas and long time scales have not yet been studied, and the capacity
of ecosystems to compensate or adjust to such CO2 induced shifts is unknown. (Section
5.2.5.2.1)
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Leakage from CO2 stored in sub-surface geological reservoirs, though considered
unlikely if sites are well selected, would have biodiversity implications on a very local
scale. CO2 storage in sub-surface geological reservoirs is already being implemented at pilotscale levels. (Section 5.2.5.2.2)
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Social, economic, cultural and ethical considerations of climate-related geo-engineering
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There are a number of social, economic and cultural considerations from geoengineering technologies that may emerge, regardless of the specific geo-engineering
approach. These considerations have clear parallels to on-going discussions on social
dimensions of climate change, emerging technologies, and complex global risks. Social
perceptions of risks, in general, are highly differentiated across social groups, and highly
dynamic, and pose particular challenges in settings defined by complex bio-geophysical
interactions. (Section 6.3)
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The very fact that the international community is presented with geo-engineering as a
potential option to be further explored is a major social and cultural issue. Humanity is
now the major changing force on the planet. This has important repercussions, not only
because it forces us to consider multiple and interacting global environmental changes, but
also because it opens up difficult discussions on whether it is desirable to move from
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unintentional modifications of the Earth system, to an approach where we intentionally try to
modify the climate and associated bio-geophysical systems to avoid the worst outcomes of
climate change. Hence, the very fact that the international community is presented with geoengineering as a potential option to be further explored is a major social and cultural issue.
(Section 6.3.1)
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Unintended side effects may result from the large-scale application of geo-engineering
techniques. This is an often-raised concern especially for Solar Radiation Management.
While technological innovation has helped to transform societies and improve the quality of
life, it has not always done so in a sustainable way. Failures to respond to early warnings of
unintended consequences of particular technologies have been documented. Accordingly,
there are calls for increased consideration of whether technological approaches are the best
option for addressing problems created by the application of earlier technologies. (Section
6.3.2)
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An additional issue is the possibility of technological, political and social “lock in” - that
is, the possibility that the development of geo-engineering technologies also result in the
emergence of vested interests and increasing social momentum. It has been argued that this
path of dependency could make deployment more likely, and/or limit the reversibility of geoengineering techniques. (Section 6.3.2)
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Ethical considerations related to geo-engineering include issues of “moral hazard” and
distributional and inter-generational issues, as well as the question of whether it is
ethically permissible to remediate one pollutant by introducing another. (Section 6.3.1)
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Geo-engineering could raise a number of questions regarding the distribution of
resources and impacts within and amongst societies and across time. First, access to
natural resources is needed for some geo-engineering. Competition for limited resources can
be expected to increase if geo-engineering techniques emerge as a competing activity for land
or water use. Second, the distribution of impacts of geo-engineering are not likely to be even
or uniform as are the impacts of climate change itself. (Section 6.3.4)
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In cases in which geo-engineering experimentation or interventions have (or are
suspected to have) transboundary effects or impacts on areas beyond national
jurisdiction, geopolitical tensions could arise regardless of causation of actual negative
impacts, especially in the absence of international agreement. Third, as with climate change,
geo-engineering could also entail intergenerational issues: future generations might be faced
with the need to maintain geo-engineering measures in general in order to avoid impacts of
climate change. (Section 6.3.5)
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Synthesis: Changes in the drivers of biodiversity loss
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In the absence of action to reduce greenhouse gas emissions, an increasingly severe
range of threats to biodiversity and ecosystem services is projected to result from
climate change and the associated phenomenon of ocean acidification. The impacts are
exacerbated by the other anthropogenic pressures on biodiversity (such as over-exploitation;
habitat loss, fragmentation and degradation; the introduction of non-native species; and
pollution). In addition, climate change is projected to actually increase the risk of some of the
other drivers. (Section 7.1)
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Climate change could be addressed by a rapid and significant reduction in greenhouse
gas emissions through a transition to a low-carbon economy with overall positive
impacts on biodiversity. Measures to achieve such a transition would avoid the adverse
impacts of climate change on biodiversity. Generally, other impacts on biodiversity of these
measures, mediated through other drivers of biodiversity loss, would be small or positive.
Although some of the measures have potential negative side-effects on biodiversity, these can
be minimized by careful design. (Section 7.1)
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The deployment of geo-engineering techniques, if feasible and effective, could reduce
some aspects of climate change and its impacts on biodiversity. At the same time, geoengineering techniques are associated with their own negative impacts on biodiversity.
The net effect will vary among techniques and is difficult to predict. Most geoengineering techniques have significant risks and uncertainties. For some techniques, there
would likely be increases in land use change, and there could also be an increase in other
drivers of biodiversity loss. (Section 7.1)
There are many areas where knowledge is still very limited. These include (i) how will the
proposed geo-engineering techniques affect weather and climate regionally and globally; (ii)
how do biodiversity and ecosystems and their services respond to changes in climate; (iii) the
direct effects of geo-engineering on biodiversity; and (iv) what are the social and economic
implications. (Section 7.3)
There is very limited understanding among stakeholders of geo-engineering concepts,
techniques and their potential impacts on biodiversity. There is also as yet little
information on the perspectives of indigenous peoples and local communities on geoengineering, especially in developing countries. Considering the role these communities play
in actively managing ecosystem, this is a major gap. (Section 7.3)
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CHAPTER 1: MANDATE, CONTEXT AND SCOPE OF WORK
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1.1. Mandate
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At the tenth meeting of the Conference of the Parties (COP-10) to the Convention on
Biological Diversity (CBD), Parties adopted a decision on climate-related geo-engineering
and its impacts on the achievement of the objectives of the CBD as part of its decision on
biodiversity and climate change.
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Specifically, in paragraph 8 of that decision, the Conference of the Parties:
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Invite[d] Parties and other Governments, according to national circumstances and
priorities, as well as relevant organizations and processes, to consider the guidance
below on ways to conserve, sustainably use and restore biodiversity and ecosystem
services while contributing to climate change mitigation and adaptation to (….)
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(w) Ensure, in line and consistent with decision IX/16 C, on ocean fertilization and
biodiversity and climate change, in the absence of science based, global, transparent
and effective control and regulatory mechanisms for geo-engineering, and in
accordance with the precautionary approach and Article 14 of the Convention, that no
climate-related geo-engineering activities2 that may affect biodiversity take place,
until there is an adequate scientific basis on which to justify such activities and
appropriate consideration of the associated risks for the environment and biodiversity
and associated social, economic and cultural impacts, with the exception of small
scale scientific research studies that would be conducted in a controlled setting in
accordance with Article 3 of the Convention, and only if they are justified by the need
to gather specific scientific data and are subject to a thorough prior assessment of the
potential impacts on the environment;
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(x) Make sure that ocean fertilization activities are addressed in accordance with
decision IX/16 C, acknowledging the work of the London Convention/London
Protocol;”
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Further, in paragraph 9 of that decision the Conference of the Parties:
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“Request[ed] the Executive Secretary to:
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(l) compile and synthesize available scientific information, and views and experiences
of indigenous and local communities and other stakeholders, on the possible impacts
of geo engineering techniques on biodiversity and associated social, economic and
cultural considerations, and options on definitions and understandings of climaterelated geo-engineering relevant to the Convention on Biological Diversity and make
it available for consideration at a meeting of the Subsidiary Body on Scientific,
Technical and Technological Advice (SBSTTA) prior to the eleventh meeting of the
Conference of the Parties; and
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(m) Taking into account the possible need for science based global, transparent and
effective control and regulatory mechanisms, subject to the availability of financial
resources, undertake a study on gaps in such existing mechanisms for climate-related
geo-engineering relevant to the Convention on Biological Diversity, bearing in mind
2
Without prejudice to future deliberations on the definition of geo-engineering activities, understanding that any
technologies that deliberately reduce solar insolation or increase carbon sequestration from the atmosphere on a
large scale that may affect biodiversity (excluding carbon capture and storage from fossil fuels when it captures
carbon dioxide before it is released into the atmosphere) should be considered as forms of geo-engineering
which are relevant to the Convention on Biological Diversity until a more precise definition can be developed.
It is noted that solar insolation is defined as a measure of solar radiation energy received on a given surface
area in a given hour and that carbon sequestration is defined as the process of increasing the carbon content of a
reservoir/pool other than the atmosphere
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that such mechanisms may not be best placed under the Convention on Biological
Diversity, for consideration by SBSTTA prior to a future meeting of the Conference
of the Parties and to communicate the results to relevant organizations.”
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Accordingly, this draft paper has been prepared by a group of experts and the CBD Secretariat
following discussions of a liaison group3 convened thanks to financial support from the
Government of the United Kingdom of Great Britain and Northern Ireland, and the
Government of Norway. The report compiles and synthesizes available scientific information
on the possible impacts of geo-engineering techniques on biodiversity, including preliminary
information on associated social, economic and cultural considerations. Related legal and
regulatory matters are treated in a separate study.
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1.2. The context for the consideration of potential impacts of geo-engineering on
biodiversity
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Biodiversity, ecosystems and their services (provisioning, regulating, cultural and supporting)
are critical to human well being. They are being directly and adversely affected by habitat
conversion, over-exploitation, the introduction of invasive species, pollution and climate
change. These in turn are being driven by demographic, economic, technological, sociopolitical and cultural changes. Protection of biodiversity and ecosystems means that we
urgently need to address these direct drivers of change.
Climate change, which is becoming increasingly important as a driver of the loss of
biodiversity and degradation of ecosystems and their services, is best addressed by a rapid and
significant reduction in greenhouse gas emissions through a transition to a low-carbon
economy in both the way we produce and use energy and the way we manage our land.
However, given the lack of international action to reduce greenhouse gas emissions, the use of
geo-engineering techniques has been suggested as an alternative or to complement efforts to
reduce greenhouse gas emissions in order to limit the magnitude of human-induced climate
change (Figure 1.1).
To assess the impact of geo-engineering techniques on biodiversity – the mandate for this
report – requires, inter alia, an evaluation of the positive and negative effects of these
techniques on the various drivers of biodiversity loss, compared to the alternatives of (i)
climate change mitigation and (ii) taking no action (or insufficient action) to address climate
change. The elements of a framework for assessing the impacts are informed by the guidance
on impact assessment developed in the framework of the Convention as discussed in the next
section of this chapter.
The assessment includes an evaluation of the benefits of reducing changes in climate through
the application of geo-engineering techniques compared to potential adverse consequences of
these techniques. Chapter 3 provides a summary of the impact of climate change on
biodiversity and ecosystems and their services as a baseline for assessing the impact of geoengineering techniques as these are only being suggested as an alternative to, or
complementary to, a transition to a low carbon economy which would directly reduce
greenhouse gas emissions. Realization of the potential positive impacts of geo-engineering
impacts on biodiversity clearly depends on the efficacy and feasibility of the techniques in
3
Lead authors are: Robert Watson (Chair), Paulo Artaxo, Ralph Bodle, Victor Galaz, Georgina Mace, Andrew
Parker, David Santillo, Chris Vivian, and Phillip Williamson. Others who provided inputs during the Liaison
Group meeting and/or commented on drafts are: Oyvind Christophersen, Ana Delgado, Tewolde Berhan Gebre
Egziabher, Almuth Ernsting, James Rodger Fleming, Tim Kruger, Ronal W. Larson, Miguel Lovera, Ricardo
Melamed, Helena Paul, Stephen Salter, Dmitry Zamolodchikov, Karin Zaunberger, and Chizoba Chinweze. The
complete list of peer reviewers will be available in the final report. The report has been edited by David Cooper,
Jaime Webbe and Annie Cung of the CBD Secretariat with the assistance of Emma Woods.
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reducing climate change or its impacts. Therefore, drawing upon earlier work, the study,
reviews any evidence in this regard in chapter 2 and chapters 4 and 5.
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Figure 1.1. Linkage between biodiversity, ecosystem goods and services and human
well-being4
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Biodiversity can affect ecosystem services directly (pathway 1) or indirectly, through
ecosystem processes (pathway 2). Both routes subsequently affect human well-being
(pathway 3).
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1.3. Relevant guidance under the Convention on Biological Diversity
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The decision on geo-engineering adopted by the Conference of the Parties at its tenth
meeting, in paragraph 8(w), refers to the precautionary approach and to Article 14 of the
Convention.
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The precautionary approach contained in Principle 15 of the Rio Declaration on Environment
and Development is an approach to uncertainty, and provides for action to avoid serious or
irreversible environmental harm in advance of scientific certainty of such harm. In the context
of the Convention, it is referred to in numerous decisions and pieces of guidance, including
inter alia in the Strategic Plan for Biodiversity 2011-2020; the ecosystem approach; the
voluntary guidelines on biodiversity-inclusive impact assessment; the Addis Ababa principles
and guidelines for the sustainable use of biodiversity; the guiding principles for the
prevention, introduction and mitigation of impacts of alien species that threaten ecosystems,
habitats or species; the programme of work on marine and coastal biological diversity; the
proposals for the design and implementation of incentive measures; the Cartagena Protocol on
Biosafety; agricultural biodiversity in the context of Genetic Use Restriction Technologies;
and forest biodiversity with regard to genetically modified trees.
4
Díaz S., Fargione J., Chapin F.S. III & Tilman D. (2006) Biodiversity loss threatens human well-being. PLoS
Biol 4, e277. doi:10.1371/journal.pbio.0040277
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In decision X/33, the Conference of the Parties calls for precaution in the absence of an
adequate scientific basis on which to justify geo-engineering activities and appropriate
consideration of the associated risks for the environment and biodiversity and associated
social, economic and cultural impacts. Further consideration of the precautionary approach is
provided in the companion study on the regulatory framework of climate-related geoengineering relevant to the Convention on Biological Diversity.
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Article 14 further includes provisions for activities which are likely to have significant
adverse effects on the biodiversity of other States or areas beyond the limits of national
jurisdiction. Given the large scale of geo-engineering interventions, the need for notification,
exchange of information and consultation as well as readiness for emergency responses called
for in this provision would likely apply to the originator of such geo-engineering activities. To
date, the Convention has not developed further guidance in this area. Equally, the issue of
liability and redress, including restoration and compensation for damage to biodiversity
caused by activities under the jurisdiction of other States is still under debate.
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These aforementioned guidelines developed under Article 14 provide useful elements that can
inform analysis of the impacts of geo-engineering on biodiversity, both at the level of specific
activities and at the level of broader assessments such as the present report.5 Given the broad
scope of the present study, the guidelines for biodiversity-inclusive strategic environmental
assessment are most relevant.
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The guidelines suggest that the following should be considered:
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(1) How the proposed techniques are expected to impact on the various components and
levels of biodiversity and across ecosystem types, the implications of this for ecosystem
services, and for the people who depend on such services;
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(2) How the proposed techniques are expected to affect the key direct and indirect drivers of
biodiversity change.
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Where such information is available, Chapters 3, 4 and 5 provide information on the various
components of biodiversity and on the range of ecosystems, the implications of this for
ecosystem services. However, in many cases such detailed information is not available. In
particular, information on the potential impacts on biodiversity at the genetic level is lacking.
Article 14 of the Convention is on impact assessment, minimizing adverse impacts as well as
liability and redress. It includes provisions on environmental impact assessment of proposed
projects as well as strategic environmental assessment of programmes and policies that are
likely to have significant adverse impacts on biodiversity. To assist Parties in this area, a set
of voluntary guidelines were developed:
 Voluntary guidelines for biodiversity-inclusive impact assessment, adopted through
decision VIII/28;
 Additional guidance on biodiversity-inclusive Strategic Environmental Assessment,
endorsed through decision VIII/28;
 Akwé:Kon voluntary guidelines for the conduct of cultural, environmental and social
impact assessment regarding developments proposed to take place on, or which are
likely to impact on, sacred sites and on lands and waters traditionally occupied or
used by indigenous and local communities, adopted through decision VII/16;
 Tkarihwaié:ri code of ethical conduct to ensure respect for the cultural and
intellectual heritage of indigenous and local communities; and
 Draft voluntary guidelines for the consideration of biodiversity in environmental
impact assessments (EIAs) and strategic environmental assessments (SEAs) in marine
and coastal areas. These seek to address governance issues including in marine areas
beyond national jurisdiction.
5
The Assessment framework developed under the London Convention/London Protocol may also be relevant
12
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At a global scale, the largest driver of terrestrial biodiversity loss has been, and continues to
be, land use change. In the oceans, overexploitation has also been a major cause of loss.
Climate change is rapidly increasing in importance as a driver of biodiversity loss. However,
the drivers of loss vary among ecosystems and from region to region6, 7. The potential impacts
of geo-engineering and of alternative actions on the drivers of biodiversity loss are briefly
considered in chapter 7.
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The CBD guidelines on impacts assessment also highlight, as key principles, stakeholder
involvement, transparency and good quality information.
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As already noted above, good quality information is often limiting. This study should
therefore be regarded as a first step in assessing the potential impacts of geo-engineering
techniques on biodiversity. The report recognizes many areas where knowledge is still very
limited. These include: (i) how will the proposed geo-engineering techniques affect weather
and climate regionally and globally; and (ii) how do biodiversity and ecosystems and their
services respond to changes in climate; (iii) the direct effects of geo-engineering on
biodiversity; and (iv) what are the social and economic implications.
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With a view to encouraging involvement of stakeholders, a number of consultations have
been held8. Moreover, this report is being made available for two rounds of peer review.
These efforts notwithstanding, it is recognized that the opportunities for full and effective
participation of stakeholders has been limited. To some extent, this is an inevitable
consequence of the relative novelty of the issue under discussion. Some indigenous and local
communities and stakeholder groups do not consider themselves sufficiently prepared to
contribute to such an effort in a full and effective manner. At the same time, it is hoped that
this report, and related efforts, will help to expand information and understanding on the
issue9.
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1.4. Scope of techniques examined in this study
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There is a range of views as to what should be considered as climate-related geo-engineering
relevant to the CBD. Approaches may include both hardware- or technology-based
engineering as well as natural processes that might have a measurable impact on the global
climate, depending on the spatial and temporal scale of interventions. Some approaches that
may be considered as geo-engineering could also be considered as climate change mitigation
and/or adaptation, for example, some ecosystem restoration activities.
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This study takes an inclusive approach without prejudice to the definition of geo-engineering
that may be agreed under the Convention or elsewhere. Examination of an intervention in this
study does not indicate that the Secretariat or the experts involved necessarily consider that
the intervention should be regarded as within the scope of the term geo-engineering.
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In particular it should be noted that COP excluded from the scope of its guidance on geoengineering (decision X/33, paragraph 8(w)) carbon capture and storage from fossil fuels
when it captures carbon dioxide before it is released into the atmosphere. However, some of
the component technologies are included in this study, where relevant.
6
Millennium Ecosystem Assessment. 2005. Ecosystems and Human Wellbeing: Synthesis. Washington (DC):
Island Press.
7 Secretariat of the Convention on Biological Diversity (2010) Global Biodiversity Outlook 3.Montréal, 94 pages.
8 - Mini-workshop on biodiversity and climate-related geo-engineering, 10 June 2011, Bonn, Germany
- Liaison Group Meeting on Climate-Related Geo Engineering as it relates to the Convention on Biological
Diversity, 29 June – 1 July, 2011, London, UK
- Informal Dialogue with Indigenous Peoples and Local Communities on Biodiversity Aspects of Geo-engineering
the Climate, Side event during the Seventh Meeting of the Ad Hoc Open-ended Working Group on Article 8(j) and
Related Provisions, 2 November 2011, Montreal, Canada
- Consultation on Climate-related Geo-engineering relevant to the Convention on Biological Diversity, Side event
during the fifteenth meeting of the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA
15), 9 November 2011, Montreal, Canada
9
Online discussion on indigenous peoples and local communities and geo-engineering, Climate Frontlines Global forum for indigenous peoples, small islands and vulnerable communities.
13
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Accordingly, the scope of the study is limited and should not be taken as a comprehensive
analysis of all matters related to geo-engineering.
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1.5. Structure of the document
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The range of techniques considered as “geo-engineering” is briefly reviewed in Chapter 2.
Chapter 2 also considers definitions for geo-engineering as it relates to the CBD based on a
compilation and summary of existing definitions.
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Geo-engineering techniques are being proposed to offset at least some of the negative impacts
of climate change, which would then be expected to have benefits for biodiversity. Therefore,
Chapter 3 provides a summary of projected climate change and the related phenomenon of
ocean acidification and the consequent impacts on biodiversity.
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The range of potential impacts on biodiversity of geo-engineering techniques are reviewed in
Chapters 4 and 5. Chapters 4 and 5 consider the potential impacts of Solar Radiation
Management (SRM) approaches and Carbon Dioxide Removal (CDR) techniques
respectively. They consider the potential impacts of geo-engineering deployed at scales
intended to reduce solar radiation to have a significant effect on global warming or sequester
a climatically significant amount of CO2 from the atmosphere, on biodiversity, where
information is available and on ecosystem services.
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A preliminary review of some of the possible social, economic and cultural impacts
associated with the impacts of geo-engineering on biodiversity is provided in Chapter 6
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Finally, some general conclusions are presented in Chapter 7.
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1.6. Key sources of information
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The study builds on past work on geo-engineering, climate change and biodiversity including
information available from the Intergovernmental Panel on Climate Change10, the Royal
Society11 the report of the IGBP workshop on Ecosystem Impacts of Geo-engineering12, the
Technology Assessment of Climate Engineering by the US Government Accountability
Office13, and CBD Technical Series reports14,15. However, it should be noted that the peerreviewed literature is rather limited and many uncertainties remain.
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While the study focuses on recent literature, it is important to note that the concept of
engineering the climate is not new16,17,18. The main focus of ideas developed in the 1950s and
1960s was however to increase, not decrease, temperatures (particularly in the Arctic), or
increase rainfall on a regional basis. However, from the 1970s, some of the examples have
10
IPPC (1995) Working Group II, Chapter 25 on Mitigation: Cross-Sectoral and Other Issues; and IPCC (2007)
Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment
Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A.
(eds.)]. IPCC, Geneva, Switzerland, 104 pp
11 The Royal Society. (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
12 Russell, L.M. et al. (2012). Ecosystem Impacts of Geoengineering: A Review for Developing a Science Plan. In
press Ambio
13 U.S. Government Accountability Office (2011) Technology Assessment: Climate engineering. Technical status,
future directions, and potential tresponses. GAO-11-71. www.gao.gov/new.items/d1171.pdf
14 Secretariat of the Convention on Biological Diversity (2009). Scientific Synthesis of the Impacts of Ocean
Fertilization on Marine Biodiversity. Technical Series No. 45. CBD, Montreal, 53 pp
15 Secretariat of the Convention on Biological Diversity (2009) Connecting Biodiversity and Climate Change
Mitigation and Adaptation: Report of the Second Ad Hoc Technical Expert Group on Biodiversity and Climate
Change. Technical Series No.41. CBD, Montreal, 126 pp
16 Lamb, H.H. (1977) Climatic History and the Future, Parts III and IV. Princeton University Press, 835 pp
17 Fleming,J.R. (2010) Fixing the Sky: The Checkered History of Weather and Climate Control. Columbia
University Press, New York, 344 pp
18 U.S. Government Accountability Office (2011) Technology Assessment: Climate engineering. Technical status,
future directions, and potential tresponses. GAO-11-71. www.gao.gov/new.items/d1171.pdf
14
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been designed to limit human-induced changes in the climate. Examples of additional historic
examples of climate control are presented in Table 1 below (a more extensive table is
available as Table 1.1 in the report of the U.S. Government Accountability Office19).
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Table 1: Some historical examples of proposals for climate related geo-engineering
Date
Who
Proposal
1877
N. Shaler
Re-routing the Pacific’s warm Kuroshio Current through the
Bering Strait to raise Arctic temperatures by around 15°C
1958
M. Gorodsky and
V. Cherenkov
Placing metallic potassium particles into Earth’s polar orbit
to diffuse light reaching Earth and thereby thaw permafrost
in Russia, Canada, and Alaska and melt polar ice
1960s
M. Budyko and others
Melting of Arctic sea-ice by adding soot to its surface
1977
C. Marchetti
Disposal of liquid CO2 to the deep ocean, via the
Mediterranean outflow
1990
J. Martin
Adding iron to the ocean to enhance CO2 drawdown
1992
NAS Committee on Science,
Engineering, and Public Policy
Adding dust to the stratosphere to increase the reflection of
sunlight
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Finally, a number of professional societies20 have considered this issue and called for further
research efforts on geo-engineering. At the same, there has already been considerable public
discussion and enunciation of social, economic and cultural issues as well as ethical
considerations and concerns raised outside of scholarly journals, for example, by civil society
organizations, indigenous communities as well as in popular books. Some reference to this
debate is also included in the document.
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19
U.S. Government Accountability Office (2011) Technology Assessment: Climate engineering. Technical status,
future directions, and potential tresponses. GAO-11-71. www.gao.gov/new.items/d1171.pdf
20
For example, the American Meteorological Society and the American Geophysical Union.
15
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CHAPTER 2: DEFINITIONS AND FEATURES OF GEO-ENGINEERING
APPROACHES AND TECHNIQUES
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2.1 Definitions of climate-Related geo-engineering relevant for the Convention on
Biological Diversity
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There is a broad range of definitions available for geo-engineering (Annex 1). Many of these
definitions contain common elements but within different formulations. A starting point is the
interim definition adopted by the Conference of the Parties to the CBD:21
“Without prejudice to future deliberations on the definition of geo-engineering
activities, understanding that any technologies that deliberately reduce solar
insolation or increase carbon sequestration from the atmosphere on a large scale
that may affect biodiversity (excluding carbon capture and storage from fossil
fuels when it captures carbon dioxide before it is released into the atmosphere)
should be considered as forms of geo-engineering which are relevant to the
Convention on Biological Diversity until a more precise definition can be
developed. It is noted that solar insolation is defined as a measure of solar
radiation energy received on a given surface area in a given hour and that carbon
sequestration is defined as the process of increasing the carbon content of a
reservoir/pool other than the atmosphere.”
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Based on the above, and consistent with the definitions listed in Annex 1, in this report:
Climate-related Geo-engineering is defined as:
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A deliberate intervention in the planetary environment of a nature and scale intended
to counteract anthropogenic climate change and/or its impacts, through, inter alia,
solar radiation management or removing greenhouse gases from the atmosphere.
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This definition includes, but is not limited to, solar radiation management (SRM) and carbon
dioxide removal (CDR) techniques with the implication that the interventions, individually, or
in combination, could, in principle, be carried out on a scale large enough to have a
significant effect on the Earth’s climate, even comparable in magnitude to anthropogenic
climate change. Unlike some others, this definition includes the removal of greenhouse gases
other than carbon dioxide. However such approaches are not further examined in this report
due to limited peer reviewed literature on the methods and their potential impacts. Further
proposed methods are potentially also covered by the above but are not given detailed
attention for the same reasons. The definition continues to exclude carbon capture and storage
from fossil fuels when it captures carbon dioxide before it is released into the atmosphere22.
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As noted in Chapter 1, there is currently a range of views concerning the inclusion or
exclusion within the definition of geo-engineering of a number of activities involving bioenergy, afforestation and reforestation, and changing land management practices.
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There is also a range of views concerning the inclusion or exclusion of weather modification
technologies, such as cloud seeding, within the definition of geo-engineering. Proponents
argue that the history, intention, institutions, technologies themselves, and impacts are closely
related to geo-engineering.23
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The above definition is broad in scope, suitable for broad-based analysis such as this study.
21
Footnote to decision X/33, paragraph 8(w)
Carbon Capture and Storage includes the storage of CO2 in depleted hydrocarbon reservoirs and saline aquifers
as well as through the injection of liquid CO2 into basalt or peridotite rocks at depth where it reacts with the rock
minerals to form calcium and magnesium carbonates.
23 As explored by the UK House of Commons Science and Technology Committee 2010 “the regulation of geoengineering: fifth report of session 2009-10; ETC Group “Geopiracy – the case against geo-engineering” 2010
22
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More specific definitions that are perhaps narrower in scope and allow for more precise legal
interpretations may be required for some purposes, such as providing policy advice and
regulation. Such definitions might be confined to specific techniques or classes of techniques.
For example, definitions relating to SRM techniques or CDR techniques that have the
potential for significant negative transboundary implications or the potential to directly affect
the global commons in a negative way may warrant separate treatment.
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2.2 Features of Solar Radiation Management and Carbon Dioxide Removal mechanisms
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Based on the definitions of geo-engineering proposed in section 2.1, this study considers a
range of both solar radiation management (SRM) techniques and carbon dioxide removal
(CDR) methods.
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When considering the potential effectiveness and impacts of such approaches, the report
examines the spatial and temporal scales at which the approaches would have to operate in
order to offset the projected changes arising from future anthropogenic emissions of
greenhouse gases. These projected changes are based on a set of scenarios for anthropogenic
emissions of greenhouse gases developed by the Intergovernmental Panel on Climate Change
(IPCC) as Special Report Emissions Scenarios (SRES) (see Chapter 3, section 3.1).
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2.2.1 Solar Radiation Management (SRM)
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Description
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Solar radiation management (SRM) techniques would counteract warming by reducing the
incidence and subsequent absorption of incoming solar (short-wave) radiation (often referred
to as insolation), not treat the root cause of anthropogenic climate change arising from
increasing greenhouse gas concentrations in the atmosphere8. SRM methods are designed to
make the Earth more reflective by increasing the planetary albedo, or by otherwise diverting
incoming solar radiation24. This provides a cooling effect, to counteract the warming
influence of increasing greenhouse gases. It may be possible that some of these techniques
could be applied to be effective within particular regions or latitude bands. This might allow
the largest counter-acting effects to be concentrated there, with lesser effects elsewhere.
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Solar radiation management would rapidly have an effect on climate once deployed at the
appropriate scale. However, SRM techniques would not address ocean acidification or the CO2
fertilization effect25. Moreover, they would introduce a new dynamic between the warming
effects of greenhouse gases and the cooling effects of SRM with uncertain climatic
implications especially at the regional scale.
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Proposed SRM techniques considered in this document comprise four main categories:
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5. Space-based approaches: reducing the amount of solar energy reaching Earth by
positioning sun-shields in space with the aim of reflecting or deflecting solar radiation;
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6. Changes in stratospheric aerosols: injecting a wide range of types of particles into the
upper atmosphere, with the aim of increasing the scattering of sunlight back to space26;
24
The Royal Society. (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
25 CO fertilization effect: Higher CO concentrations in the atmosphere increase productivity in some plant
2
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groups under certain conditions
26
Sulphur dioxide emissions into the troposphere (as currently happening from coal-fired power stations for
example) result in an increase in sulfate aerosol concentration that also reflects solar radiation and therefore have a
similar counteracting effect to stratospheric aerosols.
17
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7. Increases in cloud reflectivity: increasing the concentration of cloud-condensation nuclei
in the lower atmosphere, thereby whitening clouds with the aim of increasing the
reflection of solar radiation;
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8. Increases in surface albedo: modifying land or ocean surfaces, with the aim of
increasing the reflection of more solar radiation. This could include growing crops with
highly reflective foliage, painting surfaces in the built environment white, or covering
areas (e.g. of desert) with reflective material.
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Scope in terms of the scale of the responses
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The aim of SRM is to counteract the positive radiative forcing of greenhouse gases with a
negative forcing. To be effective in reducing a rise in global temperature, the reduction in
absorbed solar radiation would need to be a significant proportion of the increases in radiative
forcing at the top of the atmosphere caused by anthropogenic greenhouse gases. For example,
to fully counteract the warming effect of a doubling of the CO2 concentration would require a
reduction in total incoming solar radiation by about 1.8% and the absorbed heat energy by
about 4 Wm-2 (watts per square meter) as a global average.
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The impact on radiative forcing of a given SRM method is dependent on altitude (whether the
method is applied at the surface, in the atmosphere, or in space), as well as the geographical
location of its main deployment site(s). Other factors that need to be taken into account
include the negative radiative forcing of other anthropogenic emissions such as sulphate and
nitrate aerosols that together may provide a forcing of up to –2.1 Wm-2 by 210027. Such
uncertainties and interactions make it difficult to assess the scale of geo-engineering that
would be required, although quantitative estimates of the effectiveness of different techniques
have been made28.
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2.2.2 Carbon Dioxide Removal (CDR)
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Description
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Carbon Dioxide Removal (CDR) geo-engineering approaches actually involve two steps:
Carbon dioxide removal (CDR) involves techniques aimed at removing CO2, a major
greenhouse gas, from the atmosphere, allowing outgoing long-wave (thermal infra-red)
radiation to escape more easily29. In principle, other greenhouse gases (such as N2O, and
CH4), could also be removed from the atmosphere, but such approaches have yet to be
developed.
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(1) carbon sequestration or removal of CO2 from the atmosphere; and
721
(2) storage of the sequestered carbon.
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In some biologically- and chemically-driven processes, these steps occur together or are
inseparable. This is the case in ocean fertilization techniques and in the case of afforestation,
reforestation and soil carbon enhancement. In these cases the whole process, and their impacts
on biodiversity, are confined to marine and terrestrial systems respectively.
726
727
728
729
In other cases, the steps are discrete and various combinations of sequestration and storage
options are possible. Carbon sequestered in terrestrial ecosystems as biomass, for example,
could be disposed either in the ocean as plant residues or incorporated into the soil as
charcoal. It could also be used as fuel with the resultant CO2 sequestered at source and stored
27
IPCC (2007) Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth
Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and
Reisinger, A. (eds.)]. IPCC, Geneva, Switzerland, 104 pp
28 Lenton T.M. and Vaughan N.E. (2009) The radiative forcing potential of different climate geoengineering
options. Atmospheric Chemistry and Physics, 9, 5539-5561.
29 The Royal Society. (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
18
730
731
either in sub-surface reservoirs or the deep ocean. In these cases, each step will have its
advantages and disadvantages, and both need to be examined.
732
Proposed CDR removal techniques considered in this document include:
733
734
735
736
1. Ocean Fertilization: the enrichment of nutrients in marine environments with the
principal intention of stimulating primary productivity in the ocean, and hence CO2
uptake from the atmosphere, and the deposition of carbon in the deep ocean. Two
techniques may be employed with the intention of achieving these effects:
737
738
739
740
(a) Direct ocean fertilization: the artificial addition of limiting nutrients from external
(non-marine) sources. The approach includes addition of the micronutrient iron, or the
macronutrients nitrogen or phosphorus (Activities carried out as part of conventional
aquaculture are not included, nor is the creation of artificial reefs.);
741
742
743
744
745
(b) Up-welling or down-welling modification: for the specific purpose of enhancing
nutrient supply, and hence biologically-driven carbon transfer to the deep sea. (This
excludes other human activities which might cause fertilization as a side effect, for
example, by pumping cold, deep water to the surface for cooling or energy-generating
purposes);
746
747
748
2. Enhanced weathering: artificially increasing the rate by which carbon dioxide is naturally
removed from the atmosphere by the weathering (dissolution) of carbonate and silicate
rocks, including;
749
750
751
752
(a) Enhanced ocean alkalinity: adding the dissolution products of alkaline minerals (e.g.
calcium carbonate and calcium hydroxide) in order to chemically enhance ocean
storage of CO2; it also would buffer the ocean to decreasing pH, and thereby help to
counter ocean acidification;
753
754
755
(b) Enhanced weathering of rocks: silicate rocks reacting with CO2 to form solid
carbonate and silicate minerals and spreading abundant silicate minerals such as
olivine over agricultural soils;
756
3. Increasing carbon sequestration through ecosystem management30:
757
758
759
(a) Afforestation: direct human-induced conversion of land that has not been forested (for
a period of at least 50 years) to forested land through planting, seeding and/or the
human-induced promotion of natural seed sources;
760
761
762
763
764
765
(b) Reforestation: Direct human-induced conversion of non-forested land to forested land
through planting, seeding and/or the human-induced promotion of natural seed
sources, on land that was previously forested but converted to non-forested land. (For
the first commitment period of the Kyoto Protocol, reforestation activities will be
limited to reforestation occurring on those lands that did not contain forest on 31
December 1989);
766
767
768
(c) Enhancing soil carbon: through improved land management activities including
retaining captured CO2 so that it does not reach the atmosphere and enhancing soil
carbon via livestock management;
769
770
4. Sequestration of carbon as biomass and its subsequent storage – this consists of two
discrete steps, with various options for the storage step:
771
772
773
(a) Production of biomass: This can be done through the use of conventional crops, trees
and algae, and possibly also through plants bioengineered to grow faster and
sequester more carbon.
30
For the purpose of this report, the definitions of afforestation and reforestation were taken from the IPCC in
order to be consistent with the work of the CBD Second Ad hoc Technical Expert Group on Biodiversity and
Climate Change, although other definitions do exist.
19
774
775
776
(b) Bio-energy carbon capture and storage (BECCS): Bioenergy with CO2 sequestration
combining existing technology for bioenergy / biofuels and for carbon capture and
storage (geological storage);
777
778
(c) Biochar: the production of black carbon, most commonly through pyrolysis (heating,
in a low- or zero oxygen environment) and its deliberate application to soils31;
779
780
(d) Ocean biomass storage: depositing crop waste or other terrestrial biomass onto the
deep ocean seabed, possibly in high sedimentation areas;
781
782
5. Capture of carbon from the atmosphere and its subsequent storage – this consists of two
discrete steps with various options for the storage step:
783
784
785
(a) Direct carbon capture from ambient air (artificial trees): the capture of CO2 from the
air by its adsorption onto solids, its absorption into highly alkaline solutions and/or its
absorption into moderately alkaline solutions using a catalyst;
786
787
788
(b) Sub-surface storage in geological formations: storage in oil or gas fields, un-minable
coal beds, and deep saline formations such as sedimentary rocks containing high
concentrations of dissolved salts.
789
790
791
792
793
794
(c) Ocean CO2 storage: ocean storage of carbon by adding liquid CO2 (e.g. as obtained
from air capture) into the water column (i) via a fixed pipeline or a moving ship, (ii)
through injecting liquid CO2 into deep sea sediments at > 3,000 m depth or (iii) by
depositing liquid CO2 via a pipeline onto the sea floor. At depths below 3,000 m,
liquid CO2 is denser than water and is expected to form a “lake” that would delay its
dissolution into the surrounding environment;
795
796
797
798
799
800
801
As mentioned above, there is a range of views as to whether activities such as large-scale
afforestation or reforestation should be classified as geo-engineering. These approaches are
already widely deployed, albeit on a relatively small scale, for climate change mitigation as
well as other purposes, and involve minimal use of novel technologies. For the same reasons,
there is debate over whether biomass-based carbon should be included. However, for the sake
of completeness, all of these approaches are discussed in this report without prejudice to any
subsequent discussions within the CBD on definitions or policy on geo-engineering.
802
Scope in terms of the scale of the response
803
804
805
806
807
808
809
810
811
The terrestrial biosphere currently takes up about 2.6 GtC (gigatonnes of carbon) per year
from the atmosphere, although this is partially offset by carbon dioxide emissions of about 0.9
GtC per year from tropical deforestation and other land use changes. In comparison, the
current CO2 release rate from fossil fuel burning alone is about 9.1 GtC/yr 32; so to have a
significant positive impact, one or more CDR interventions would need to involve the
removal from the atmosphere of several GtC/yr, maintained over decades and more probably
centuries. It is very unlikely that such approaches could be deployed on a large enough scale
to alter the climate quickly, and so they would be of little help if there was a need for
‘emergency action’ to cool the planet on a short time scale.
812
2.2.3 Comparison between SRM and CDR techniques
813
814
Although described above separately, it is possible that, if geo-engineering were to be
undertaken, a combination of SRM and CDR techniques could be used, alongside mitigation
31
Spokas, K. (2010). Review of the stability of biochar in soils: predictability of O:C molar ratios, Carbon
Management (2010) 1(2), 289–30)
32
Global Carbon Project (2011) Carbon budget and trends 2010. www.globalcarbonproject.org/carbonbudget,
released 4 December 2011.
20
815
816
817
818
819
820
821
822
823
through emission reductions, with the objective of off-setting at least some of the impacts of
changes to the climate system from past or ongoing emissions. While SRM and CDR
interventions would both have global effects, since climate operates on a global scale, some of
the proposed SRM interventions (e.g. changing cloud albedo) could result in strong
hemispheric or regional disparities, e.g. with regard to changes in the frequency of extreme
events. Under conditions of rapid climate change, the unequivocal separation of impact
causality between those arising from the SRM intervention and those that would have
happened anyway would not be easy. Likewise, CDR techniques will ultimately reduce global
CO2 concentrations but may affect local to regional conditions more in the short term.
824
825
826
827
828
829
830
831
832
833
In general, SRM techniques can have a relatively rapid impact on the radiation budget once
deployed, whereas the effects of many of the CDR processes are relatively slow.
Furthermore, while SRM techniques offset the radiative effects of all greenhouse gases, they
do not alleviate the potential impacts of changes in atmospheric chemistry, such as ocean
acidification. In contrast, most (but not all) CDR techniques do address changes in
atmospheric CO2 concentrations, but they do not address the radiative effects of increased
atmospheric concentrations of non-carbon dioxide greenhouse gases (e.g. methane, nitrous
oxide, tropospheric ozone, halocarbons) and black carbon. Furthermore, whilst some CDR
techniques would reduce ocean acidification, that benefit is compromised to varying degrees
if the CO2 removed from the atmosphere is subsequently added to the ocean.
834
835
836
837
838
839
840
To facilitate further comparison between techniques, Tables 2.1 and 2.2 summarize SRM and
CDR approaches respectively and provide a simplified assessment of their effectiveness, cost
readiness, risks and reversibility. The assessments are based primarily upon those provided in
the peer-reviewed Royal Society Report33 with further details provided in the legend to the
tables. They address primarily risks to the climate system and its biogeophysical implications
and do not necessarily reflect broader implications for ecosystem services or social impacts.
Further discussion of the risks is included in Chapters 4 and 5.
841
842
843
It should be noted that the estimates provided for each of the criteria in these assessments are
relative. With regard to readiness, for example, the GAO report ranks all geo-engineering
technologies as immature (low technology readiness level (TRL) 2 or 3 on a scale of 1 to 9).34
844
845
846
847
848
Clearly, interventions that are deemed to be safe are highly preferable, but, given the high
levels of uncertainty associated with geo-engineering, in case the safety evaluation is
incorrect, then interventions with a relatively short time to reverse any adverse effects are, by
many, deemed preferable because the unintended consequences can be reversed relatively
quickly.
849
850
851
852
853
854
855
856
857
858
859
However, it should be noted that for any listed geo-engineering technique to be effective over
the long-term, it would need to be continued for decadal to century timescales (and potentially
for millennia), or until such time as the atmospheric levels of greenhouse gases have been
stabilised at levels that no longer present unacceptable danger to ecosystems, food production
and economic development (possibly to below current levels). This ‘treadmill’ problem is
particularly acute for SRM interventions, whose intensity would need to be progressively
increased unless other actions are taken to stabilise greenhouse gas concentrations. The
cessation of SRM interventions would also be a highly risky process, and if, after being
deployed for some time, were to be carried out rapidly, would likely result in a rapid increase
in the solar radiation reaching the Earth’s surface, and associated very rapid increase in
surface temperature35. Thus, high reversibility could have both advantages and disadvantages.
33
The Royal Society. (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
34 U.S. Government Accountability Office (2011) Technology Assessment: Climate engineering. Technical status,
future directions, and potential responses. GAO-11-71. www.gao.gov/new.items/d1171.pdf
35
In one model simulation, the rate was up to 20 times greater than present-day rates. Matthews H.D. and Caldeira
K. (2007) Transient climate-carbon simulations of planetary geoengineering. PNAS, 104, 9949-9954
21
860
2.2.3 Additional speculative techniques:
861
862
863
864
865
866
867
868
869
870
In addition to the SRM and CDR techniques described above, a number of other highly
speculative approaches have been mooted. These have not been evaluated and are not
discussed further in this report. They include some approaches based on increasing the rate of
loss of long-wave heat radiation. One is to reduce the amount of cirrus clouds by injection of
an appropriate substance to form ice particles as a sink for upper tropospheric water vapour.
Another is to use icebreakers to open up passages in the fall and winter in order to reduce the
insulating effect of the Arctic ice (so more heat is transferred from the ocean to the
atmosphere), thus promoting the thickening of adjacent ice (and so increasing the amount of
reflected solar radiation the next spring). Using micron-size bubbles in water to increase
albedo and cool the water has been proposed36.
871
872
873
There are also other types of approaches that might involve land surface modification, such as
draining seawater into the Qattara Depression to limit sea level rise, or blocking the Bering
Strait to promote formation of sea ice.
36
Proposed by Seitz, R. (2011) Bright water: hydrosols, water conservation and climate change. Climatic Change.
Doi:10.1007/s10584-010-9965-8; however see Robock, A. (2011). "Bubble, bubble, toil and trouble." Climatic
Change 105: 383-385 DOI: 10.1007/s10584-010-0017-1
22
874
Table 2.1: Classification of SRM techniques and summary of features
Technique(s)
Mechanism
Scale
OA?
Relative
Direct
Cost
Notes to the columns (see below)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
Space-based reflectors
High
Large
No
V.High
V.Low
Moderate
Moderat
e
Moderate
Medium
Stratospheric aerosols
High
Large
No
Low
Moderate
Fast
High
High
Fast
Cloud reflectivity
Medium
Medium
No
Moderate
Moderate
Fast
High
High
Fast
Built environment
High
Small
No
V.High
Moderate
Fast
Low
Low
Medium
Crops
High
Medium
No
Moderate
Moderate
Fast
Low
Medium
Fast
Deserts
High
Large
No
V.High
Moderate
Fast
V.High
V.High
Medium
Surface albedo
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
Relative Effectiveness
Relative Readiness
To deploy
To Act
Relative Risks and
Uncertainty
Risk
Uncertainty
Relative
Reversibility
Notes to the columns of tables 2.1 and 2.2:
The assessments are based primarily upon those provided in the peer-reviewed Royal Society Report. They address primarily risks to the climate system and its biogeophysical implications and
do not necessarily reflect broader implications for ecosystem series or social impacts. The risks are further discussed in Chapters 4 and 5. The estimates provided for each of the criteria in these
assessments are relative.
Effectiveness: a measure of the potential of geo-engineering techniques to offset impacts of climate change and, specifically, for SRM techniques to modify solar radiation and for CDR
techniques to sequester CO2 from the atmosphere. Three sub-criteria are provided: (1) The degree of evidence that the mechanism would actually work, based on theoretical understanding
and, where appropriate, experimental results; (2) The potential scale of operation: For CDR, ‘Large’ is several GtC per year; ‘Medium’ is about 1 GtC per year; and ‘small’ is less than 0.1
GtC per year. For SRM, ‘Large’ is several Wm-2; ‘Medium’ is about 1 Wm-2; and ‘Small’ is less than 0.1 Wm-2; (3) Whether or not the technique also addresses the problem of ocean
acidification;
Cost (4) estimate of the cost of deploying the technology on a significant scale;
Readiness: including
(5) a measure of whether a technique to either affect solar radiation or reduce the atmospheric concentration of CO2, and hence impact on the earth’s climate, can be deployed on a largescale within 10 years. This measure refers purely to technical readiness, and excludes what is economically, socially and politically possible. A technology might be ready to deploy
tomorrow, but impossible to deploy due to economic, social or political obstacles.
(6) How quickly the technology, once deployed, would act to offset climate change effects on a significant scale:
Risk: a measure of the potential for adverse effects of a technique, including:
(7) risk of anticipated negative effects and the magnitude of those effects
(8) Probability of unanticipated negative effects (uncertainty)
Reversibility: (9) the degree to which the impact of a geo-engineering intervention is safely reversible if it is found to have unintended adverse environmental consequences. As with the
‘Readiness’ measure, ‘Reversibility’ reflects a purely technological point of view, regardless of the termination effect. A geo-engineering technology might be technically reversible, but
impossible to reverse due to economic, social and political concerns (e.g. employment, vested interests, etc.).
23
897
Table2.2: Classification of CDR techniques and summary of features
Technique(s)
Relative
Location of
Impacts
Relative Effectiveness
Capture
Mechanism
Scale
OA?
(1)
(2)
(3)
Storage
Notes (see legend to Table 2.1 and below)
Relative
Cost
Relative
Readiness
Relative Risks and
Uncertainty
Relative
Reversibilty
To
deploy
To Act
Risk
Uncertaint
y
(4)
(5)
(6)
(7)
(8)
(9)
Fe
– Ocean –
Poor
Small
No
Low
Medium
Slow
High
V.High
Medium
N/P
– Ocean –
Poor
V.Small
No
Moderate
Medium
Slow
High
V.High
Medium
up/downwelling modification
– Ocean –
V. Poor
Unknown
No
Unknown
V. low
Unknown
V.High
V.High
Unknown
2. Enhanced
weathering
Ocean alkalinity (ocean)
– Ocean+ –
Good
Large
Yes
High
Low
Slow
Moderate
Moderate
None
Spreading of base minerals
–
–
Good
Large
Yes
High
Low
Slow
Moderate
Moderate
None
3. Terrestrial
Ecosystem
management
Afforestation
– Land –
Good
Small
Yes
Moderate
High
Medium
Low-Mod
Low
Medium
Reforestation
– Land –
Good
Small
Yes
Moderate
High
Medium
Low
Low
Medium
Soil carbon enhancement
– Land –
Good
Small
Yes
Moderate
High
Slow
Low
Low
Medium
1. Ocean
Fertilization
4. Biomass
5. Air Capture &
CO2 Storage
direct external
fertilization
Land+
Biomass Production
Land
na
Medium
Medium
Yes
Moderate
High
Slow
Moderate
Moderate
Medium
Biofuels with CCS
na
Sub-S
Medium
Medium
na
High
Medium
Low
Moderate
Moderate
Slow
Charcoal storage
Land
Medium
Small
Moderate
Medium
Low
Moderate
Moderate
Slow
Ocean biomass storage
Ocean
Poor
Small
High
Low
Low
High
High
None
Air capture
Either
na
High
Medium
Yes
V.High
Low
Medium
Low
Low
na
Ocean CO2 storage
na
Ocean
Low
Medium
na
High
Low
Low
V. High
High
None
Sub-S
Good
Medium
High
Low
Low
Moderate
Moderate
na
Sub-surface CO2 reservoirs
+
Ocean alkalinity: will also have indirect impacts on land through mining and transport of materials.
+
Spreading of alkaline minerals: will eventually have impacts (largely positive) on oceans through run-off to oceans.
24
898
899
CHAPTER 3: OVERVIEW OF CLIMATE CHANGE AND OCEAN
ACIDIFICATION AND OF THE THEIR IMPACTS ON BIODIVERSITY
900
901
902
903
904
905
Geo-engineering techniques are being proposed to counteract some of the negative impacts of
climate change, which include impacts on biodiversity. This chapter therefore provides an
overview of projected climate change (Section 3.1) and its impacts on biodiversity and
ecosystems (Section 3.2), in order to provide context, and a possible baseline which can be
taken into account when the impacts of geo-engineering techniques are reviewed in
subsequent chapters.
906
907
3.1 Overview of projected climate change and ocean acidification.
908
909
910
911
912
913
914
915
916
917
Human activities have already increased the concentration of greenhouse gases, such as CO 2,
in the atmosphere. These changes affect the Earth’s energy budget, and are considered to be
the main cause of the ~0.8°C average increase in global surface temperature that has been
recorded over the last century37. The continued increase in atmospheric greenhouse gases has
profound implications not only for global and regional average temperatures, but also
precipitation, ice-sheet dynamics, sea-level rise, ocean acidification and the frequency and
magnitude of extreme events. Future climatic perturbations could be abrupt or irreversible,
and are likely to extend over millennial time scales; they will inevitably have major
consequences for natural and human systems, severely affecting biodiversity and incurring
very high socio-economic costs.
918
3.1.1 Scenarios and models
919
920
921
922
923
924
925
926
927
The Intergovernmental Panel on Climate Change (IPCC) developed future scenarios for
anthropogenic emissions of greenhouse gases in its Special Report on Emissions Scenarios
(SRES). These were grouped into four families (A1, A2, B1 and B2) according to
assumptions regarding the rates of global economic growth, population growth, and
technological development38. The SRES A1 family includes three illustrative scenarios
relating to dependence on fossil fuels (A1FI, fossil fuel intensive; A1B, balanced; and A1T,
non-fossil energy sources); the other families each have only one illustrative member. The B1
scenario assumes the rapid introduction of resource-efficient technologies, together with
global population peaking at 8.7 billion in 2050.
928
929
930
931
932
933
934
935
The six SRES illustrative scenarios were used in the IPCC’s fourth assessment report (AR4)
in a suite of climate change models to estimate a range of future global warming of 1.1 to
6.4°C by 2100, with a ‘best estimate’ range of 1.8 to 4.0°C (Figures 3.1 and 3.2)39. A 7th
scenario assumed that atmospheric concentrations of greenhouse gases remain constant at
year 2000 values. Note in Fig 3.2 the very large regional differences in temperature increase,
and between land and ocean areas, with increases of up to 7°C for the Arctic. The projected
precipitation changes also have high spatial variability, with both increases and decreases of
~20% in most continents.
936
37
Intergovernmental Panel on Climate Change (IPCC). 2008. Climate Change 2007 – Synthesis Report.
Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel
on Climate Change. Pachauri R.K. & Resinger A. (Eds). IPCC, Geneva, Switzerland, pp 104.
38
Intergovernmental Panel on Climate Change (IPCC). 2000. Emissions Scenarios. Nakicenovic N. & Swart R.
(Eds). Cambridge University Press, UK, pp 570.
39 Intergovernmental Panel on Climate Change (IPCC). 2008. Climate Change 2007 – Synthesis Report.
Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel
on Climate Change. Pachauri R.K. & Resinger A. (Eds). IPCC, Geneva, Switzerland, pp 104.
25
937
938
Figure 3.1: Illustrative scenarios for greenhouse gas annual emissions from 2000
to 2100
939
940
941
942
943
944
945
946
947
948
949
Left: Six illustrative scenarios for greenhouse gas annual emissions from 2000 to 2100, as
gigatonnes of CO2 equivalent. Greenhouse gases include CO2, CH4, N2O and F-gases. The
gray shaded area shows the 80th percentile range of other scenarios published since the IPCC
Special Report on Emission Scenarios; the dashed lines [labelled post-SRES (max) and postSRES (min)] show the full range of post-SRES scenarios. Right: Vertical bars show range of
temperature increases and best estimates for IPCC’s six illustrative emission scenarios, based
on multi-model comparisons between 1980-1999 and 2090-2099. Temporal changes in
global surface warming also shown graphically for scenarios A2, A1B and B1 (red, green and
dark blue lines respectively), with pink line showing temperature change if atmospheric
concentrations of greenhouse gases could be held constant at year 2000 values.
950
951
Figure 3.2: Projected patterns of temperature increase and precipitation change
952
953
26
954
955
956
957
958
Projected increase in annual mean temperature (upper map) and percentage precipitation
change (lower maps; left, December to February; right, June to August) for the SRES A1B
scenario, based on multi-model comparisons between 1980-1999 and 2090-2099. Couloured
areas on precipitation maps are where >66% of the models agree in the sign of the change;
for stippled areas, >90% of the models agree in the sign of the change.
959
960
961
962
963
964
965
IPCC AR4 estimated global sea level rise (relative to 1990) to be 0.2 to 0.6 m by 2100;
however, those projections excluded ice sheet changes. Taking such effects into account,
more recent empirical estimates40 give projected sea level increases of 0.4 – 2.1 m, with
similar values obtained from measurements of ice-sheet mass balance41, although with large
uncertainties relating to current loss rates (particularly for Antarctica)42. Future sea level
change will not be globally uniform43: regional variability may be up to 10-20 cm for a
projected global end-of-century rise of around 1 m.
966
967
968
969
970
971
972
973
974
975
976
977
The broad pattern of climate change observed since ~1850 has been consistent with model
simulations, with high latitudes warming more than the tropics, land areas warming more than
oceans, and the warming trend accelerating over the past 50 years. Over the next 100 years,
interactions between changes in temperature and precipitation (Figure 3.2) will become more
critical; for example, affecting soil moisture and water availability in both natural and
managed ecosystems. These effects are likely to vary across regions and seasons, although
with marked differences between model projections. By 2050, water availability may
increase by up to 40% in high latitudes and some wet tropical areas, while decreasing by as
much as 30% in already dry regions in the mid-latitudes and tropics44. Additional analyses45
of 40 global climate model projections using the SRES A2 scenario indicate that Northern
Africa, Southern Europe and parts of Central Asia could warm by 6-8°C by 2100, whilst
precipitation decreases by ≥10%.
978
979
980
981
982
The IPCC SRES scenarios can be considered inherently optimistic, in that they assume
continued improvements in the amounts of energy and carbon needed for future economic
growth. Such assumptions have not recently been met46; if future improvements in energy
efficiency are not achieved, emissions reductions may need to be up to three times greater47
than estimated in AR4.
983
984
985
986
A new generation of emission scenarios giving greater awareness to such issues is currently
under development48 for use in the IPCC fifth assessment report (AR5). These will include
both baseline and mitigation scenarios, with emphasis on Representative Concentration
Pathways (RCPs) and cumulative emissions to achieve stabilization of greenhouse gas
40
Rahmstorf S. 2010. A new view on sea level rise. Nature Reports Climate Change. Published online 6 April
2010; doi: 10.1038/climate.2010.29
41
Rignot E., Velicogna I., van den Broeke M.R., Monaghan A. & Lenaerts J. 2011. Acceleration of the
contribution of the Greenland and Antarctic ice sheets to sea level rise. Geophysical Research Letters, 38,
L05503, doi: 10.1029/2011GL046583
42 Zwally H.J. & Giovinetto M.B. 2011. Overview and assessment of Antarctic ice-sheet mass balance estimates:
1992-2009. Surveys in Geeophysics, 32, 351-376; doi: 10.1007/s10712-011-9123-5
43
Milne G.A., Gehrels W.R., Hughes C.W. & Tamisiea M.E. 2009. Identifying the causes of sea level change.
Nature Geosciences 2, 471-478.
44 Intergovernmental Panel on Climate Change (IPCC). 2008. Climate Change 2007 – Synthesis Report.
Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on
Climate Change. Pachauri R.K. & Resinger A. (Eds). IPCC, Geneva, Switzerland, pp 104.
45 Sanderson M.G, Hemming D.L & Betts R.A. 2011. Regional temperature and precipitation changes under highend (≥4°C) global warming. Phil. Trans. R. Soc. A, 369, 85-98; doi: 10.1098/rsta.2010.0283
46 Pielke R., Wigley T. & Green C. 2008. Dangerous assumptions. Nature, 452, 531-2
47
Pielke R., Wigley T. & Green C. 2008. Dangerous assumptions. Nature, 452, 531-2
48
UNFCCC Subsidiary Body for Scientific and Technological Advice. 2011. Report on the Workshop on the
Research Dialogue, 34th SBSTA session, Bonn 6-16 June 2011, FCCC/SBSTA/2011/INF.6 (paras 19-23 and 3738). http://unfccc.int/resource/docs/2011/sbsta/eng/inf06.pdf
27
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concentrations at various target levels, linked to their climatic impacts. For example,
stabilization at 450, 550 and 650 ppm CO2eq (carbon dioxide equivalent; taking account of
anthropogenic greenhouse gases and aerosols in addition to carbon dioxide), is expected to
provide around a 50% chance of limiting future global temperature increase to 2°C, 3°C and
4°C respectively. Note that anthropogenic sulphate aerosols have a negative CO2eq value;
thus if their emissions are reduced, the rate of warming would increase.
993
3.1.2 Current trajectories for climate change
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One of the goals of the United Nations Framework Convention on Climate Change is to
prevent dangerous anthropogenic interference in the climate system. This aim is stated in the
UNFCCC Objective (Article 2 of the Convention):
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1003
“The ultimate objective of this Convention and any related legal instruments that the
Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions
of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level
that would prevent dangerous anthropogenic interference with the climate system. Such a
level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally
to climate change, to ensure that food production is not threatened and to enable economic
development to proceed in a sustainable manner.”
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1005
1006
1007
1008
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1010
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However, there are both political and technical difficulties in deciding what ‘dangerous’
means in terms of equivalent temperature increase and other climate changes (and hence
CO2eq stabilization value). The Copenhagen Accord49 recognized “the scientific view that the
increase in global temperature should be below 2°C”, which equates to a target of around 400450 ppm CO2eq. Currently the ensemble of greenhouse gases and aerosols are equivalent to
around 495 ppm CO2eq, but the cooling effect of anthropogenic sulphate aerosols offset
around 100 ppm CO2eq. Progress towards achieving emission reduction targets for
greenhouse gases has been recently reviewed50,51.
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Lower stabilization targets have also been proposed52,53,54 on the basis that a 2°C temperature
increase represents an unacceptable level of climate change55. To achieve these lower targets,
reductions from current CO2eq levels (i.e. negative emissions, through CDR geo-engineering)
would almost certainly be needed.
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Since 2000, the average rate of increase in global greenhouse gas emissions has been 3.1%
per year (Figure 3.3) )56,57 matching or exceeding the rates of the highest IPCC SRES
49
50
51
UNFCCC. 2010. Copenhagen Accord. http://unfccc.int/resource/docs/2009/cop15/eng/107.pdf
UNEP. 2011. Bridging the Emissions Gap. United Nations Environment Programme (UNEP), 52 pp;
www.unep.org/pdf/UNEP_bridging_gap.pdf
IAEA. 2011. Climate Change and Nuclear Power 2011. International Atomic Energy Authority (IAEA). 40 pp.
www.iaea.org/OurWork/ST/NE/Pess?assets/11-43751_ccnp_brochure.pdf
52
Rockström J. et al. 2009. Planetary boundaries: exploring the safe operating space for humanity. Ecology and
Society, 14, Article 32; www.ecologyandsociety.org/vol14/iss2/art32
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Hansen J. et al. 2008. Target atmospheric CO2: where should humanity aim? Open Atmos. Sci. J., 2, 217-231; doi
10.2174/1874282300802010217
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Veron J.E.N. et al. 2009. The coral reef crisis: the critical importance of <350 ppm CO2. Marine Pollution
Bulletin, 58, 1428-1436; doi: 10.1016/j.marpolbul.2009.09.009
Anderson K. & Bows A. 2011. Beyond ‘dangerous’ climate change: emission scenarios for a new world. Phil.
Trans. Roy. Soc. A. 369, 20-44; doi: 10.1098/rsta.2010.0290
55
56
Peters GP, Marland G, Le Quéré C, Boden T, Canadell JG, Raupach MR. 2011. Rapid growth in CO2 emissions
after the 2008-2009 global financial crisis. Nature Climate Change, doi. 10.1038/nclimate1332; published online 4
Dec 2011.
28
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scenarios for that period (A1B, A1FI and A2) despite the Kyoto Protocol and the recent
global economic downturn. As a result, it has become much more challenging to achieve the
450 ppm CO2eq target. For example, for ~50% success in reaching that target, it has been
estimated that global greenhouse gas emissions would need to peak in the period 2015-2020,
with an annual reduction of emissions of >5% thereafter58. Whilst such changes in emissions
are not unrealistic for some developed countries, at the global level, the necessary planning
(and political will) for radical changes in energy infrastructure and associated economic
development59,60,61 are not yet in place. If such efforts are not made, geo-engineering
approaches will increasingly be postulated to offset at least some of the impacts of climate
change, despite the risks and uncertainties involved.
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Figure 3.3. Global emissions of CO2 for 1980-2010 in comparison to IPCC SRES
emission scenarios for 2000-202562.
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The average rate of increase of CO2 emissions since 2000 has been around 3% per year
(increasing atmospheric concentrations by ~2 ppm per year), tracking the highest IPCC
emission scenarios used for AR4 climate projections. The increase in emissions in 2010 was
5.9%, the highest total annual growth recorded.
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57
Global Carbon Project. 2011. Carbon budget and trends 2010. www.globalcarbonproject.org/carbonbudget,
released 4 Dec 2011.
58
Anderson K. & Bows A. 2008. Reframing the climate change challenge in light of post-2000 emission trends.
Phil. Trans. Roy. Soc. A, 366, 3863-3882; doi: 10.1098/rsta.2008.0138
59 Brown L.R. (2011) World on the Edge. How to Prevent Environmental and Economic Collapse. Earth Policy
Institute; www.earth-policy.org/books/wote
60
UNEP 2011. Bridging the Emissions Gap. United Nations Environment Programme (UNEP), 52 pp;
www.unep.org/pdf/UNEP_bridging_gap.pdf
61
IAEA. 2011. Climate Change and Nuclear Power 2011. International Atomic Energy Authority (IAEA). 40 pp.
www.iaea.org/OurWork/ST/NE/Pess?assets/11-43751_ccnp_brochure.pdf
62
Le Quéré, C. 2011. The response of the carbon sinks to recent climate change, and current and expected
emissions in the short term from fossil fuel burning and land use. Presentation at UNFCCC SBSTA Workshop,
Bonn 2-3 June 2011;
http://unfccc.int/files/methods_and_science/research_and_systematic_observations/application/pdf/15_le_quere_re
sponse_of_carbon_sinks.pdf
29
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Climate-carbon-cycle feedbacks were not included in all of the climate models used for AR4
(but will be included in AR5). Ensemble-based analyses63 of the A1FI scenario with such
feedbacks matched the upper end of the AR4 projections, indicating that an increase of 4°C
relative to pre-industrial levels could be reached as soon as the early 2060s. The omission of
non-linearities, irreversible changes64 and tipping points65 from global climate models makes
them more stable than the real world. As a result of that greater stability, models can be poor
at simulating previous abrupt climate change due to natural causes66. However, the recent
improvements in Earth system models (and computing capacity) give increasing confidence
in their representations of future climate-ecosystem interactions.
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Even with strong climate mitigation policies, further climate change is inevitable due to
lagged responses in the Earth climate system (so-called unrealized warming). Thus, increases
in global mean surface temperature of 0.3 - 2.2oC are projected to occur over several centuries
after atmospheric concentrations of greenhouse gases have been stabilized67, with associated
increases in sea level due to thermally-driven expansion and ice-melt. Due to the long
residence time of CO2 in the atmosphere, it is an extremely slow and difficult process to
return to a CO2 stabilisation target once this has been exceeded. For other short-lived
greenhouse gases, climate system behaviour also prolongs their warming effects68. Figure 3.4
shows the modelled decline in atmospheric CO2 concentrations based on the assumption that
emissions could be instantly reduced to zero after peaks of 450-850 ppm had been reached.
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Figure 3.4: Changes in atmospheric CO2 concentrations based on emission cessation
after certain levels of CO2 have been reached69
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63
Betts R.A. et al. 2011. When could global warming reach 4°C? Phil. Trans. R. Soc. A, 369, 67-84; doi:
10.1098/rsta.2010.0292
64
Solomon S., Plattner G.-K., Knutti R. & Friedlingstein P. 2009. Irreversible climate change due to carbon
dioxide emissions. Proc. Natl. Acad. Sci U.S.A, 106, 1704-1709; doi: 10.1073/pnas.0812721106
65 Lenton T.M. et al. 2008. Tipping elements in the Earth’s climate system. Proc. Natl. Acad. Sci. U.S.A., 105,
1786-1793; doi:10.1073/pnas.0705414105
66 Valdes P. 2011. Built for stability. Nature Geosciences 4, 414-416; doi: 10.1038/ngeo1200
67 Plattner G.-K. et al 2008. Long-term climate commitments projected with climate-carbon cycle models. 2008.
Journal of Climate, 21, 2721-2751
68
Solomon S et al. 2010. Persistence of climate changes due to a range of greenhouse gases. Proc. Natl. Acad. Sci.
U.S.A., 107, 18354-18359
69
Solomon S., Plattner G.-K., Knutti R. & Friedlingstein P. 2009. Irreversible climate change due to carbon
dioxide emissions. Proc. Natl. Acad. Sci U.S.A, 106, 1704-1709; doi: 10.1073/pnas.0812721106
30
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Even if anthropogenic CO2 emissions could be abruptly halted, atmospheric CO2 levels are
projected to remain much higher than pre-industrial values for at least the next thousand
years.
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Such lag effects have particular importance for ocean acidification. Thus, changes in surface
ocean pH (due to the solubility of CO2, and the formation of carbonic acid) closely follow the
changes in atmospheric CO2. The penetration of such pH changes to the ocean interior is,
however, very much slower, depending on the century-to-millennium timescale of ocean
mixing70,71.
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Differences between the behaviour and impacts of different greenhouse gases and aerosols are
not discussed in detail here, but are also very important. For example: tropospheric ozone,
methane and black carbon all have relative short atmospheric lifetimes, and therefore may be
amenable to emission control with relatively rapid benefits, not only to climate but also
human health (black carbon) and agricultural productivity (tropospheric ozone)72. Black
carbon particles have significant heating effect on the lower troposphere and potential effect
on the hydrological cycle through changes in cloud microphysics, and snow and ice surface
albedo73.
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3.2 Observed and projected impacts of climate change, including ocean acidification, on
biodiversity
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3.2.1 Overview of climate change impacts on biodiversity
70
The Royal Society. 2005. Ocean acidification due to increasing atmospheric carbon dioxide. Policy document
12/05, Royal Society, London; 60 pp. http://royalsociety.org/Ocean-acidification-due-to-increasing-atmosphericcarbon-dioxide
71 Joos, F., Frölicher T.L., Steinacher M. & Plattner G-K. (2011) Impact of climate change mitigation on ocean
acidification projections. In: Ocean Acidification (Eds: J.-P. Gattuso & L. Hansson), Oxford University Press, p
272- 290.
72 UNEP-WMO. Integrated Assessment of Black Carbon and Troposheric Ozone. Summary for Decision Makers.
www.wmo.int/pages/prog/arep/gaw/other_pub.html
73
Ramanathan V & Carmichael G. 2008. Global and regional climate changes due to black carbon. Nature
Geoscience 1, 221-227; doi: 10.1038/ngeo156
31
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Temperature, rainfall and other components of climate strongly influence the distribution and
abundance of species; they also affect the functioning of ecosystems, through species
interactions. Whilst vegetation shifts, population movements and genetic adaptation have
lessened the impacts of previous, naturally-occurring climate change (e.g. during
geologically-recent ice age cycles)74, the scope for such responses is now reduced by other
anthropogenic pressures on biodiversity, including over-exploitation; habitat loss,
fragmentation and degradation75; the introduction of non-native species; and pollution, and
the rapid pace of projected climate change. Thus, anthropogenic climate change carries a
higher extinction risk76, since the abundance (and genetic diversity) of many species is
already much depleted. Human security may also be compromised by climate change 77,78,
with indirect (but potentially serious) biodiversity consequences in many regions.
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Whilst some species may benefit from climate change, many more will not. Observed impacts
and adaptation responses arising from anthropogenic climate changes that have occurred to
date include the following79:
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
Shift in geographical distributions towards higher latitudes and (for terrestrial species) to
higher elevations80. This response is compromised by habitat loss and anthropogenic
barriers to range change;
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
Phenological changes relating to seasonal timing of life-cycle events;
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
Disruption of biotic interactions, due to differential changes in seasonal timing; e.g.
mismatch between peak of resource demand by reproducing animals and the peak of
resource availability;
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
Changes in photosynthetic rates and primary production in response to CO2 fertilization
and increased nutrient availability (nitrogen deposition and coastal eutrophication).
Overall, gross primary production is expected to increase, although fast growing species
are likely to be favoured over slower growing ones, and different climate forcing agents
(e.g. CO2, tropospheric ozone, aerosols and methane) may have very different effects81.
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As noted above, the AR4 estimates future global warming to be within the range 1.1°C to
6.4°C by 2100. Five reasons for concern for a similar temperature range had been previously
identified in the IPCC’s third assessment report82, relating to risks to unique and threatened
(eco)systems; risks of extreme weather events; disparities of (human) impacts and
vulnerabilities; aggregate damages to net global markets; and risks of large-scale
discontinuities. These reasons for concern were re-assessed using the same methodology83,
74
Jackson S.T. & Overpeck J.T. 2000. Responses of plant populations and communities to environmental changes
of the late Quaternary. Paleobiology 26 (sp4): 194-220
75 Ellis E. 2011. Anthropogenic transformation of the terrestrial biosphere. Phil Trans. Roy. Soc. A, 369, 10101035; doi: 10.1098/rsta.2010.0331
76 Maclean I.M.D. & Wilson R.J. 2011. Recent ecological responses to climate change support predictions of high
extinction risk. PNAS (online); doi 10.1073/pnas.1017352108.
77 Barnett J. & Adger W.N. 2007. Climate change, human security and violent conflict. Political Geography 26,
639-655.
78 Hsiang S.M., Meng K.C., & Cane M.A. 2011. Civil conflicts are associated with the global climate. Nature, 476,
438-441.
79 Secretariat of the Convention on Biological Diversity. 2009. Connecting Biodiversity and Climate Change
Mitigation and Adaptation. Report of the Second Ad Hoc Technical Expert Group on Biodiversity and Climate
Change. Montreal, Technical Series No. 41, 126 pages.
80 Cheng I.-C., Hill J.K., Ohlemüller R., Roy D.B. & Thomas C.D. 2011. Rapid range shift of species associated
with high levels of climate warming. Science 333, 1024-1026
81 Huntingford C. et al. 2011. Highly contrasting effects of different climate forcing agents on terrestrial
ecosystem services. Phil. Trans. Roy. Soc. A, 369, 2026-2037; doi: 10.1098/rsta.2010.0314
82 Smith J.B., Schellnhuber H.-J. & Mirza M.M.Q. 2001. Vulnerability to climate change and reasons for concern:
a synthesis. Chapter 19 in IPCC Third Assessment Report, Working Group II, p 913-967. Cambridge University
Press, Cambridge, UK.
83 Smith J. B. et al. 2009. Assessing dangerous climate change through an update of the Intergovernmental Panel
32
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with the conclusion that smaller future increases in global mean temperature – of around 1°C
– lead to high risks to many unique and threatened systems, such as “coral reefs, tropical
glaciers, endangered species, unique ecosystems, biodiversity hotspots, small island states and
indigenous communities” (Figure 3.5).
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Figure 3.5: Projected impacts of global warming, as “Reasons for Concern”
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Updated “reasons for concern” plotted against increase in global mean temperature84. Note
that: i) this figure relates risk and vulnerability to temperature increase without reference to a
future date; ii) the figure authors state that the colour scheme is not intended to equate to
‘dangerous climatic interference’ (since that is a value judgement); and iii) there was a
marked worsening of the authors’ prognosis in comparison to an assessment published 8
years earlier, using the same methodologies.
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The relatively specific and quantifiable risk of rate of extinction was assessed by the CBD’s
Second Ad hoc Technical Expert Group on Biodiversity and Climate Change, with the
estimate that ~10% of species will be at risk of extinction for every 1°C rise in global mean
temperature85. A recent meta-analysis86 provides a similar, although lower, estimate,
indicating that extinction is likely for 10-14% of all species by 2100. Irreversible losses at
such scales must inevitably lead to adverse impacts on many ecosystems and their services 87,
with negative social, cultural and economic consequences. Due to the complex nature of the
climate-biodiversity link, there will inevitably be uncertainty about the extent and speed at
which climate change will impact biodiversity, species interactions88, ecosystem services, the
on Climate Change (IPCC) ‘‘reasons for concern’’. Proc. Natl. Acad. Sci. U.S.A., 106: 4133–4137. doi:
10.1073/pnas.0812355106
84
Smith J.B., Schellnhuber H.-J. & Mirza M.M.Q. 2001. Vulnerability to climate change and reasons for concern:
a synthesis. Chapter 19 in IPCC Third Assessment Report, Working Group II, p 913-967. Cambridge University
Press, Cambridge, UK.
85 Secretariat of the Convention on Biological Diversity (2009) Connecting Biodiversity and Climate Change
Mitigation and Adaptation: Report of the Second Ad Hoc Technical Expert Group on Biodiversity and Climate
Change. Technical Series No. 41. CBD, Montreal, 126 pp
86 Maclean I.M.D. & Wilson R.J. 2011. Recent ecological responses to climate change support predictions of high
extinction risk. PNAS (online); doi 10.1073/pnas.1017352108.
87
Isbell F., Calcagno V., Hector A., Connolly J., Harpole W.S., Reich P.B., Scherer-Lorenzen M., Schmid B,
Tilman D, van Ruiven J., Weigelt A., Wilsey B.J., Zavaleta E.S. & Loreau M. 2011. High plant diversity is needed
to maintain ecosystem services. Nature (online) doi: 10.1038/nature10282
88 Brooker R.W., Travis J.M.J, Clark E.J. & Dytham C. 2007. Modelling species range shifts in a changing
climate: The impacts of biotic interactions, dispersal distance and rate of climate change. J Theoretical Biology,
33
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thresholds of climate change above which ecosystems no longer function in their current
form89, and the effectiveness of potential conservation measures90,91.
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3.2.2 Projected impacts on terrestrial ecosystems
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The geographical locations where greatest terrestrial biodiversity change might be expected
has been assessed using multi-model ensembles and SRES A2 and B1 emission scenarios to
predict the appearance or disappearance of new and existing climatic conditions 92 (Figure
3.6). The A2 scenario indicates that, by 2100, 12-39% of the Earth’s land surface will
experience novel climatic conditions (where the 21st century climate does not overlap with
20th century climate); in addition, 10-48% will experience disappearing climatic conditions
(where the 20th century climate does not overlap with the 21st century climate).
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Figure 3.6: Novel and disappearing terrestrial climatic conditions by 2100
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Model projections of novel (upper) and disappearing (lower) terrestrial climatic conditions
by 2100. Left-hand maps: based on A2 emission scenario; right-hand maps: based on B1
emission scenario. Novel climatic conditions are projected to develop primarily in the tropics
and subtropics. Disappearing climatic conditions are concentrated in tropical montane
regions and the poleward portions of continents. Scale shows relative change, with greatest
impact at the yellow/red end of the spectrum.
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Montane habitats (e.g. cloud forests, alpine ecosystems) and endemic species have also been
identified93 as being particularly vulnerable because of their narrow geographic and climatic
ranges, and hence limited – or non-existent – dispersal opportunities. Other terrestrial and
coastal habitats considered to be at high risk include tundra ecosystems, tropical forests and
mangroves. For coastal habitats, rising sea level will be an additional environmental stress.
245, 59-65
89 Pereira H.M., et al. 2010. Scenarios for global biodiversity in the 21st century. Science, 330, 1496-1501.
90 Hoegh-Guldberg O., Hughes L., McIntyre S., Lindenmayer D.B., Parmesan C., Possingham H.P. & Thomas
C.D. 2008. Assisted colonization and rapid climate change. Science, 321, 345-346.
91 Dawson T.P., Jackson S.T., House J.I., Prentice I.C. & Mace G.M. 2011. Beyond predictions: biodiversity
conservation in a changing climate. Science, 332, 53-58.
92 Williams J.W., Jackson S.T. & Kutzbach J.E. 2007. Projected distributions of novel and disappearing climates by
2100 AD. Proc. Natl. Acad. Sci. U.S.A., 104, 5738-5742; doi: 10.1073/pnas.0606292104
93
Secretariat of the Convention on Biological Diversity (2009) Connecting Biodiversity and Climate Change
Mitigation and Adaptation: Report of the Second Ad Hoc Technical Expert Group on Biodiversity and Climate
Change. Technical Series No. 41. CBD, Montreal, 126 pp
34
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A more physiological approach to assessing climatic vulnerability and resilience found that
temperate terrestrial ectotherms (cold-blooded animals, mostly invertebrates) might benefit
from higher temperatures, whilst tropical species, already close to their optimal temperature,
would be disadvantaged even though the amount of change to which they will be exposed is
smaller (Figure 3.7)94. More limited data for vertebrate ectotherms (frogs, lizards and turtles)
demonstrated a similar pattern indicating a higher risk to tropical species from climate
change. In temperate regions, insect crop pests and disease vectors would be amongst those
likely to benefit from higher temperatures (with negative implications for ecosystem services,
food security and human health), particularly if their natural predators are disadvantaged by
climate change.
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In general, vulnerability to climate change across species will be a function of the extent of
climate change to which they are exposed relative to the species’ natural adaptive capacity.
This capability varies substantially according to species biology and ecology, as well as
interactions with other affected species. Species and ecosystems most susceptible to decline
will be those that not only experience high rates of climate change (including increased
frequency of extreme events), but also have low tolerance of change and poor adaptive
capacities95.
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Figure 3.7: Projected impact of projected future warming (for 2100) on the fitness of
terrestrial ectotherms96
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Latitudinal impacts of climate change, based on thermal tolerance. A) and B), insect data;
map shows negative impacts in blue, positive impacts in yellow/red. C), comparison of
latitudinal change in thermal tolerance for insects with more limited data for turtles, lizards
and frog.
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Given their importance in the carbon cycle, the response of forest ecosystems to projected
climate change is a critical issue for natural ecosystems, biogeochemical feedbacks and
human society97. Key unresolved issues include the relative importance of water availability,
seasonal temperature ranges and variability, the frequency of fire and pest abundance, and
94
Deutsch C.A. et al 2008. Impacts of climate warming on terrestrial ectotherms across latitude. Proc. Natl. Acad.
Sci. U.S.A., 105, 6668-6672; doi: 10.1073/pnas.0709472105
95 Dawson T.P., Jackson S.T., House J.I., Prentice I.C. & Mace G.M. 2011. Beyond predictions: biodiversity
conservation in a changing climate. Science, 332, 53-58.
96 Deutsch C.A. et al 2008. Impacts of climate warming on terrestrial ectotherms across latitude. Proc. Natl. Acad.
Sci. U.S.A., 105, 6668-6672; doi: 10.1073/pnas.0709472105
97 Bonan G. 2008. Forests and climate change: forcings, feedbacks, and the climate benefit of forests. Science,
320, 1444-1449; doi: 10.1126/science.1155121
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constraints on migration rates. Whilst tropical forests may be at risk, recent high resolution
modelling has given some cause for optimism98, in that losses in one region may be offset by
expansion elsewhere.
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3.2.3 Projected impacts on marine ecosystems
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The marine environment is also vulnerable to climate change, with the additional stress of
ocean acidification. Although, future surface temperature changes (with the exception of the
Arctic) may not be as high as on land (Figure 3.2), major poleward distributional changes
have already been observed; for example, involving population movements of hundreds and
thousands of kilometres by fish99 and plankton100,101 respectively in the North East Atlantic.
Increases in marine pathogenic bacteria have also been ascribed to climate change102.
1200
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For temperate waters, increases in planktonic biodiversity (in terms of species numbers) have
recently occurred in response to ocean warming103. Such changes do not, however,
necessarily result in increased productivity nor benefits to ecosystem services, e.g. fisheries.
In the Arctic, the projected loss of year-round sea ice this century104 is likely to enhance
pelagic biodiversity and productivity, but will negatively impact charismatic mammalian
predators (polar bears and seals). The loss of ice will also re-connect the Pacific and Atlantic
Oceans, with potential for major introductions (and novel interactions) for a wide variety of
taxa via trans-Arctic exchange105.
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Marine species and ecosystems are also increasingly subject to an additional and yet closely
linked threat: ocean acidification. Such a process is an inevitable consequence of the increase
in atmospheric CO2: this gas dissolves in sea water, to form carbonic acid; subsequently,
concentrations of hydrogen ions and bicarbonate ions increase, whilst levels of carbonate ions
decrease.
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By 2100, a pH decrease of 0.5 units in global surface seawater is projected under SRES
scenario A1FI106. corresponding to a 300% increase in the concentration of hydrogen ions.
This may benefit small-celled phytoplankton (microscopic algae and cyanobacteria), but
could have potentially serious implications for many other marine organisms, including
commercially-important species that are likely to be subject to thermal stress107. Experiments
on ocean acidification impacts have given variable results, with some species showing
positive or neutral responses to lowered pH; nevertheless, a meta-analysis108 of 73 studies
98
Zelazowski P, Malhi Y, Huntingford C, Sitch S. & Fisher J.B. 2011. Changes in the potential distribution of
humid tropical forests on a warmer planet. Phil. Trans. Roy. Soc. A, 369,, 137-160; doi: 10.1098/rsta.2010.0238
99 Perry A.L., Low P.J., Ellis J.R. & Reynolds J.D. 2005. Climate change and distribution shifts in marine fishes.
Science 308,1912-1915; doi: 10.1126/science.1111322
100
Beaugrand, G., Reid, P.C., Ibanez, F., Lindley, J.A. & Edwards, M. 2002. Reorganization of North Atlantic
marine copepod biodiversity and climate. Science, 296:1692-1694.
101 Perry A.L., Low P.J., Ellis J.R. & Reynolds J.D. 2005. Climate change and distribution shifts in marine fishes.
Science 308,1912-1915; doi: 10.1126/science.1111322
102 Vezzuli, L., Brettar, I., Pezzati, E., Reid, P.C., Colwell, R.R., Höfle, M.G. & Pruzzo, C. (2011) Long-term
effects of ocean warming on the prokaryotic community: evidence from the vibrios. The ISME Journal. advance
online publication; doi: 10.1038/ismej.2011.89
103 Beaugrand, G., Edwards, M. & Legendre, L (2010) Marine biodiversity, ecosystem functioning, and carbon
cycles. Proc. Nat. Acad. Sci. USA, 107, 10120-10124; doi: 10.1073/pnas.0913855107
104 Boé, J., Hall, A. & Qu, X. (2009) September sea-ice cover in the Arctic Ocean projected to vanish by 2100.
Nature geosciences, 2, 341-343; doi: 10.1038/ngeo467
105 Greene C.H., Pershing A.J., Cronin T.M. & Ceci N. 2008. Arctic climate change and its impacts on the ecology
of the North Atlantic. Ecology, 89 (Supplement),S24–S38
106 Caldeira K. & Wickett M.E. 2005. Ocean model predictions of chemistry changes from carbon dioxide
emissions to the atmosphere and ocean. J. Geophysical Research- Oceans, 110, C09S04
107 Secretariat of the Convention on Biological Diversity. 2009. Scientific Synthesis of the Impacts of
Ocean Acidification on Marine Biodiversity. Montreal, Technical Series No. 46, 61 pp
108 Kroeker K.J., Kordas R.L., Crim R.N. & Singh G.G. 2010. Meta-analysis reveals negative yet variable effects
of ocean acidification on marine organisms. Ecology Letters 13, 1419-1434; doi: 10.1111/j.1461-0248.2010.01518.x
36
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showed that laboratory survival, calcification and growth were all significantly reduced when
a wide range of organisms was exposed to conditions likely to occur in 2100 (Figure 3.8).
For a recent overview, including pH effects on physiology and energy metabolism, see
Gattuso & Hansson109 .
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Figure 3.8: Meta-analysis of experimental studies on effect of pH change projected for
2100
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Effect of pH decrease of 0.4 units on reproduction, photosynthesis, growth, calcification
and survival under laboratory conditions for a wide taxonomic range of marine organisms.
Mean effects and 95% confidence limits calculated from log-transformed response ratios,
here re-converted to a linear scale. Redrawn with lead author’s permission110.
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The threshold for ‘dangerous’ ocean acidification has yet to be defined at the
intergovernmental level, in part because its ecological impacts and economic consequences
are currently not well quantified111,112. An atmospheric CO2 stabilisation target of 450 ppm
could still risk large-scale and ecologically-significant impacts. Thus, at that level: 11% of the
surface ocean would experience a pH fall of >0.2 relative to pre-industrial levels; only 8% of
present-day coral reefs would experience conditions considered optimal for calcification,
compared with 98% at pre-industrial atmospheric CO2 levels113; and around 10% of the
surface Arctic Ocean would be aragonite-undersaturated for part of the year114 (increasing
metabolic costs for a wide range of calcifying organisms). Potentially severe local impacts
could occur elsewhere in upwelling regions and coastal regions115, with wider feedbacks116.
109
Gattuso J_P & Hansson L. (eds) 2011. Ocean Acidification. Oxford University Press, 326 pp..
110
Kroeker K.J., Kordas R.L., Crim R.N. & Singh G.G. 2010. Meta-analysis reveals negative yet variable effects of
ocean acidification on marine organisms. Ecology Letters 13, 1419-1434; doi: 10.1111/j.14610248.2010.01518.x
111 Turley, C., Eby, M., Ridgwell, A.J., Schmidt, D.N., Findlay, H.S., Brownlee, C., Riebesell, U., Gattuso, J.-P.,
Fabry, V.J. & Feely R.A. (2010) The societal challenge of ocean acidification. Mar. Poll. Bull. 60, 787–792.
112 Cooley, S. R. & Doney, S.C. (2009) Anticipating ocean acidification’s economic consequences for commercial
fisheries. Environ. Res. Letters 4, 024007, doi: 10.1088/1748-9326/4/2/024007
113 Cao, L. & Caldeira, K. (2008) Atmospheric CO stabilization and ocean acidification. Geophy. Res. Letters 35,
2
L19609; doi: 10.1029/2008GL035072
114 Steinacher, M., Joos, F., Frölicher, T.L., Plattner, G.-K. & Doney, S.C. (2009) Imminent ocean acidification in
the Arctic projected with the NCAR global coupled carbon cycle-climate model. Biogeosciences 6, 515-533; doi:
10.5194/bg-6-515-2009
115 Feely, R.A., Alin, S.R., Newton, J., Sabine, C.L., Warner, M., Devol, A., Krembs, C. & Maloy, C. (2010) The
combined effects of ocean acidification, mixing, and respiration on pH and carbonate saturation in an urbanized
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Both cold water and tropical corals seem likely to be seriously impacted by ocean
acidification; however, the latter are especially vulnerable since they are also subject to
temperature stress (coral bleaching), coastal pollution (eutrophication and increased sediment
load) and sea-level rise. Population recovery time from bleaching would be prolonged if
growth is slowed due to acidification (together with other stresses), although responses are
variable and dependent on local factors117. The biodiversity value of corals is extremely high,
since they provide a habitat structure for very many other organisms; they protect tropical
coastlines from erosion; they have significant biotechnological potential; and they are highlyregarded aesthetically. More than half a billion people are estimated to depend directly or
indirectly on coral reefs for their livelihoods118.
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3.3.4 The role of biodiversity in the Earth System and in delivering ecosystem services
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The biosphere plays a key role in the Earth system, especially as part of the global cycles of
carbon, nutrients and water, thereby providing ecosystem services of immense human value.
Interactions between species/ecosystems and a very wide range of other natural and humandriven processes must therefore also be considered when assessing the impacts of climate
change (and geo-engineering) on biodiversity. The conservation and restoration of natural
terrestrial, freshwater and marine biodiversity are essential for the overall goals of both the
CBD and UNFCCC, not only on account of ecosystems’ active role in global cycles but also
in supporting adaptation to climate change.
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Carbon is naturally sequestered and stored by terrestrial and marine ecosystems, through
biologically-driven processes. The amount of carbon in the atmosphere, ~750Gt, is much less
than the ~2,500 Gt C stored in terrestrial ecosystems119; a further 1,000 Gt C occurs in the
upper layer of the ocean, and an additional ~37,000 Gt C is stored in the deep ocean,
exchanging with the atmospheric over relatively long time scales. On average ~160 Gt C
exchange annually between the biosphere (both ocean and terrestrial ecosystems) and
atmosphere. Proportionately small changes in ocean and terrestrial carbon stores, caused by
changes in the balance of exchange processes, might therefore have large implications for
atmospheric CO2 levels. Such a change has already been observed: in the past 50 years, the
fraction of CO2 emissions that remains in the atmosphere each year has slowly increased,
from about 40% to 45%, and models suggest that this trend was caused by a decrease in the
uptake of CO2 by natural carbon sinks, in response to climate change and variability120.
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It is therefore important to improve our representation of biogeochemical feedbacks (mostly
driven by plants and microbes, on land and in the ocean) in Earth system models – not just
climate models – in order to understand how biodiversity may influence, and be influenced
by, human activities. The range of non-climatic factors important in this context, as direct
and indirect drivers of biodiversity change, and the range of ecosystem goods and services
that are involved are summarised in Figure 1.1.
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3.4 Projected socio-economic and cultural impacts of climate change
estuary. Est. Coastal & Shelf Sci. 88, 442-449; doi: 10.1016/j.ecss.2010.05.004
116 Gehlen, M., Gruber, N., Gangstø R., Bopp, L. & Oschlies, A. (2011) Biogechemical consequences of ocean
acidification and feedbacks toi the Earth system. In: Ocean Acidification (Ed: J.-P. Gattusso & L. Hansson),
Oxford University Press, p 230- 248.
117 Pandolfi J.M., Connolly S.R., Marshall D.J. & Cohen A.L. 2011. Projecting Coral Reef Futures Under Global
Warming and Ocean Acidification. Science, 333, 418-422.
118 TEEB. 2009. The Economics of Ecosystems and Biodiversity: Climate Issues Update, September 2009.
www.unep.ch/etb/ebulletin/pdf/TEEB-ClimateIssuesUpdate-Sep2009.pdf
119 Ravindranath, N.H. & Ostwald, M. 2008., Carbon Inventory Methods Handbook for Greenhouse Gas
Inventory, Carbon Mitigation and Roundwood Production Projects. Springer Verlag, Advances in Global Change
Research, pp 304, ISBN 978-1-4020-6546-0.
120 Le Quere C., Raupach M.R., Canadell J.G., Marland G. & et al. 2009. Trends in the sources and sinks of carbon
dioxide. Nature Geosciences, 2, 831-836.
38
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The scientific literature on the societal implications of projected climate change is vast, and a
detailed assessment is inappropriate here. Nevertheless, a very brief overview of the socioeconomic consequences of current trajectories is necessary, to complete the conceptual
picture of linkages between climate, biodiversity, ecosystems, ecosystem goods and services,
and human well-being, as indicated in Fig 3.9 above. Such considerations provide important
context for the discussion of how geo-engineering (with its own impacts) might be used
counteract climate change. Chapter 6 gives additional attention to the socio-economic and
cultural aspects of geo-engineering.
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The Stern Review121 estimated that, without action, the overall costs of climate change would
be equivalent to a future annual loss of 5-20% of gross domestic product. Although that
analysis was much discussed122 and criticised by some economists, a similar range and scale
of projected economic impacts of climate change were identified in the IPCC Fourth
Assessment Report (Working Group II). Table 3.1 summarises those findings on a regional
basis. The IPCC Fifth Assessment Report, now nearing completion, will provide additional
information, using improved projections (e.g. for sea level rise) and a wider range of impacts
(e.g. including ocean acidification).
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Table 3.1. Examples of some projected socio-economic impacts of climate change for
different regions (all with very high or high confidence). Information from IPCC AR4
Synthesis Report123
Africa
 By 2020, agricultural yields reduced by up to 50% in some countries, affecting food security
and exacerbating malnutrition. 75-250 million people exposed to increased water stress.
 By 2080, arid and semi-arid land likely to increase by 5-8%.
 By 2100, sea level rise will affect low-lying coastal areas with large populations; adaptation
costs could be at least 5-10% of Gross Domestic Product
Asia
 By 2050, decreased freshwater availability in Central, South,East and South-East Asia,
 Coastal areas, especially heavily populated regions in South, East and South-East Asia, at
increased flooding risk from the sea (and, in some megadeltas, river flooding)
 Associated increased risk of endemic morbidity and mortality due to diarrhoeal disease
Australia
and New
Zealand
 By 2020, significant biodiversity loss in the Great Barrier Reef, Queensland Wet Tropics and
other ecologically rich sites
 By 2030, reduced agricultural and forest production over much of southern and eastern
Australia, and parts of New Zealand, due to increased drought and fire.
 By 2050, ongoing coastal development and population growth exacerbate risks from sea level
rise and increases in the severity and frequency of storms and coastal flooding.
Europe
 Negative impacts include increased risk of inland flash floods and more frequent coastal
flooding and increased erosion (due to storminess and sea level rise).
 Mountainous areas will experience glacier retreat, reduced snow cover and species losses of
up to 60% by 2080 (under high emissions scenarios).
 In southern Europe, reduced water availability, hydropower potential, summer tourism and
crop productivity, together with increased health risks due to heat waves and wildfires.
Latin
America
 By 2050, gradual replacement of tropical forest by savanna in eastern Amazonia; elsewhere
semi-arid vegetation will tend to be replaced by arid-land vegetation. Associated risk of
significant biodiversity loss through species extinction
121
Stern N. 2006. The Economics of Climate Change. The Stern Review. 712 pp, Cambridge University Press,
Cambridge, UK
122
Barker et al. 2008. Special Topic: The Stern Review Debate (6 editorials and 8 related papers). Climatic
Change, 89, 173-446.
123
IPCC. 2008. Climate Change 2007 – Synthesis Report. Contribution of Working Groups I, II and III to the
Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Pachauri R.K. & Resinger A.
(Eds). IPCC, Geneva, Switzerland, 104 pp.
39
 Decreased productivity of many crops and livestock, with adversely affecting food security.
 Hydrological changes are expected to significantly affect water availability for human
consumption, agriculture and energy generation.
North
America
 Moderate climate change is projected to increase yields of rain-fed agriculture by 5-20%, but
with important variability among regions. Major challenges expected for crops near the warm
end of their suitable range or which depend on highly utilised water resources.
 Increased number, intensity and duration of heat waves during the course of the century, with
potential for adverse health impacts.
 Coastal communities and habitats will be increasingly stressed by climate change impacts
interacting with development and pollution.
Polar
Regions
 Reductions in thickness and extent of glaciers, ice sheets and sea ice; changes in natural
ecosystems include adverse effects on migratory birds, mammals and higher predators.
 For human communities in the Arctic, impacts are projected to be mixed; detrimental impacts
include those on infrastructure and traditional indigenous ways of life.
 In both polar regions, specific ecosystems and habitats are projected to be vulnerable, as
climatic barriers to species invasions are lowered.
Small
Islands
 Sea level rise is expected to exacerbate inundation, storm surge, erosion and other coastal
hazards, threatening vital infrastructure that supports the livelihood of island communities.
 Reduced water resources in many small islands, e.g. in the Caribbean and Pacific, may
become insufficient to meet demand during low-rainfall periods.
 Higher temperatures will increase frequency of coral bleaching and, for mid- and high-latitude
islands, the risk of invasion by non-native species.
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CHAPTER 4: POTENTIAL IMPACTS ON BIODIVERSITY OF SOLAR
RADIATION MANAGEMENT GEO-ENGINEERING TECHNIQUES
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As summarised in Chapter 3, if climate change continues unchecked, it will pose an
increasingly severe range of threats to biodiversity and ecosystem services. However, climate
change is just one of many factors influencing biodiversity loss. Effective actions to reduce
the magnitude of climate change would be expected to reduce climate change-related threats
to biodiversity. However, they may be augmented or offset by the proximate impacts of the
measure itself. Thus if a proposed SRM measure can be shown to likely be feasible and
effective in reducing the negative impacts of climate change, these projected positive impacts
need to be considered alongside any projected negative impacts of the geo-engineering
measure.
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This chapter explores whether and how SRM techniques – in general and individually – might
be able to reduce climate-imposed threats to biodiversity and ecosystem services. It also
examines the potentially damaging side effects of SRM techniques, as well as the
uncertainties surrounding their impacts.
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Carbon Dioxide Removal (CDR) techniques are examined in Chapter 5.
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This chapter first examines the projected positive and negative impacts that are common to all
SRM techniques (section 4.1). Then the impacts specific to particular techniques are reviewed
(section 4.2).
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4.1. Potential impacts on biodiversity of a generic SRM approach that results in uniform
dimming.
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4.1.1. Potential reduction in temperature and other climate change effects from SRM that
results in uniform dimming
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To date, most studies of the potential impacts of SRM have consisted of observations of the
natural world (e.g. volcanic eruptions) or computer modelling. Models have typically
examined a world in which SRM is assumed to bring about uniform dimming to counter
increased climate change (e.g. a world with doubled CO2). Their results suggest that almost
all areas of the planet would experience significantly less temperature change in the world of
high greenhouse gases together with a uniform dimming of solar radiation, than with climate
change alone124.
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In general, modelling suggests that overall changes to precipitation would not be any worse
than the world with climate change, and at best there would be significantly less change in
most regions. However, the positive impacts of the technique on reducing changes in
temperature and precipitation are least in equatorial regions, among the most biodiverse
regions. These simulations suggest that SRM, if feasible and effective in creating uniform
dimming, could reduce the overall global changes in temperature and rainfall resulting from
climate change, but could also lead to some geographical redistribution of the effects of
climate change125,126.
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The speed with which SRM would be expected to reduce temperatures (see section 2.2.1) is a
unique attribute of these techniques. While SRM would start reducing temperature
immediately after deployment at scale, it would take decades (or longer) for emissions cuts or
124
Caldeira, K, and Wood, L, 2008, Global and Arctic climate engineering: numerical model studies.
Philosophical Transactions of the Royal Society A, 366, 366, 4039-4056. doi:10.1098/rsta.2008.0132
125 Caldeira, K, and Wood, L, 2008, Global and Arctic climate engineering: numerical model studies.
Philosophical Transactions of the Royal Society A, 366, 366, 4039-4056. doi:10.1098/rsta.2008.0132.
126 K. Ricke, G. Morgan, M. Allen (2010) Regional climate response to solar radiation management. Nature
Geosciences, 3: 537-541.
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CDR deployment to lower global temperatures. This means that SRM would be the only
approach known to date that might allow a rapid reduction in temperatures should it be
deemed necessary.
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Overall, if the cooling from SRM was realised as models project, it would be expected to
reduce many of the impacts of climate change on biodiversity. However, only limited
modelling work has been done and many uncertainties remain concerning the side effects of
SRM techniques on biodiversity (as noted in the following sections). It is therefore not
possible to predict the net effect with any degree of confidence. Scientists are also unable to
predict with a high degree of confidence which areas might experience changes in
temperature and precipitation under SRM deployment, and even further from being able to
predict which ecosystems, and elements thereof, might be affected, and how.
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The uncertainty surrounding regional climatic changes in a 2xCO2 world and a 2xCO2 + SRM
world stems from the uncertain nature of climate modelling. The specific regional results
from individual climate models cannot be relied upon since, as the IPCC’s model intercomparisons have demonstrated127, different models generate a wide diversity of regional
climate projections for high CO2 futures. In some regions, the results of most models
converge, giving a relatively high degree of confidence that regional projections are correct.
However, in other regions, there is no agreement among climate model projections. No intercomparisons have yet been carried out for SRM models, although one is currently underway
for stratospheric geo-engineering with sulphate aerosols128. Owing to these modelling
uncertainties, it is currently difficult to conclude with high confidence on how a uniform
deployment of SRM might affect biodiversity and ecosystem services in a given region.
However, a recent paper suggests that regional inequalities from SRM that results in uniform
dimming may not be as severe as is often assumed129 (Section 4.1.3).
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SRM would introduce a new dynamic between the heating effects of greenhouse gases and
the cooling effects of SRM. The combination of changes – high CO2 and other greenhouse
gases concentrations, unpredictably altered precipitation patterns, and in some cases more
diffuse light, – would be unlike any known combination that extant species and ecosystems
have experienced in their evolutionary history. However, it is not clear whether the
environment of the SRM world would be more or less challenging for any particular species
and ecosystems than that caused by the climate change that it would be seeking to counter
(Section 4.1.3).
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There are a number of other potential implications of SRM. As described in section 4.1.2, it
introduces a new dynamic between the warming effects of CO2 and the cooling effects of
SRM.
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Figure 4.1: Temperature changes resulting from two experimental simulations
127
S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L Miller (eds) (2007)
Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate
Change. IPCC, Cambridge, UK and New York, NY, USA.
128 Ben Kravitz et al, 2011, The Geoengineering Model Intercomparison Project (GeoMIP), Atmospheric Science
Letters. Available online at http://climate.envsci.rutgers.edu/pdf/GeoMIP10.1002-asl.316.pdf
129 Moreno Cruz et al 2011
42
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Panels (a) and (b) show change in mean annual surface temperature and its statistical
significance with twice the CO2 concentration of the pre-industrial era, and (c) and (d) show
projected temperature change and its statistical significance with a uniform 1.84% reduction
of insolation.
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Figure 4.2: Precipitation changes resulting from two experimental
simulations
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Panels (a) and (b)show change in total annual precipitation and its statistical significance
with twice the CO2 concentration of the pre-industrial era, and (c) and (d) show projected
precipitation change and its statistical significance with a uniform 1.84% reduction of
insolation.
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4.1.2 Projected impacts of deploying a generic SRM technique on hydrological and nutrient
cycles
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While modelling to date has generally indicated that climate-induced changes to precipitation
are likely to be reduced under SRM deployment (compared with a 2xCO2 world130,131), it is
hard to extrapolate what the implications would be for biodiversity and ecosystem services.
Precipitation minus evaporation is a much more useful metric of biologically available water
than is precipitation alone132,133, with soil moisture the key hydrological variable for healthy
terrestrial ecosystems. Under SRM deployment, one might expect soil moisture to decrease as
precipitation decreases, soil moisture to increase as insolation decreases (since
evapotranspiration would be reduced), and soil moisture to increase as CO2 increases (since
plants would use less water).
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Combining these various observations leads to the conclusion that soil moisture would
increase overall under SRM, assuming that CO2 levels continue to increase. Such a conclusion
is extremely tentative however, given the lack of modelling and model inter-comparisons to
date. Conversely, some modelling has indicated that soil moisture would probably decline in
the tropics134,135. Changes in soil moisture have implications for terrestrial ecosystem services
since they affect Net Primary Productivity (NPP)136,137.
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SRM could have both predictable and unknown side effects on the atmospheric cycling of
nutrients and their deposition138. It is not known whether SRM would counteract the changes
to nutrient cycles expected in a 2xCO2 world. In the absence of any nutrient cycle modeling, it
is impossible to predict with any degree of certainty what the consequent implications for
biodiversity and ecosystem services might be.
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4.1.3 Projected impacts of deploying a generic SRM technique on species and ecosystems
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Reducing temperature through deployment of SRM might benefit those species identified in
Chapter 3 as being particularly vulnerable to the negative impacts of increased temperature
due to climate change, including for example: stranded species; species of arctic ecosystems,
mountain ecosystems and the northern extreme of northern islands. Long-lived non-mobile
species such as many k-strategist trees, which are poor at adapting to climate change, are also
likely to be favoured. So too, potentially, are most species that reproduce slowly. It is
plausible, although not yet known, that species with temperature-regulated sex determination
might also do better under SRM deployment than under climate change alone.
130
Caldeira, K, and Wood, L, 2008, Global and Arctic climate engineering: numerical model studies.
Philosophical Transactions of the Royal Society A, doi:10.1098/rsta.2008.0132
131 A. Jones, J. M. Haywood and O. Boucher, 2010, A comparison of the climate impacts of geoengineering by
stratospheric SO2 injection and by brightening of marine stratocumulus cloud, Atmospheric Science Letters, 12 (2):
176-183.
132 G. A.Ban-Weiss and K.Caldeira, 2010, Geoengineering as an optimization problem, Environmental Research
Letters, 5: 1-9.
133 Steve Running and John Kimball, 2006, Satellite-based analysis of ecological controls for land-surface
evaporation resistance, Encyclopedia of Hydrological Sciences, DOI: 10.1002/0470848944.hsa110.
134 G. Bala, P.B. Duffy and K.E. Taylor (2008) Impacts of geoengineering schemes on the global hydrological
cycle. Proceedings of the National Academy of Sciences of the United States of America, 105 (22): 7664-7669.
135 H.D. Matthews and K. Caldeira (2007) Transient climate-carbon simulations of planetary geoengineering.
Proceedings of the National Academy of Sciences of the United States of America, 104 (24): 9949-9954.
136 A. Jones, J. M. Haywood and O. Boucher, 2010, A comparison of the climate impacts of geoengineering by
stratospheric SO2 injection and by brightening of marine stratocumulus cloud, Atmospheric Science Letters, 12 (2):
176-183.
137 H. D. Matthews and K. Caldeira, 2007, Transient climate-carbon simulations of planetary geoengineering,
PNAS, 104: 9949-9954.
138 B. Kravitz, A. Robock, L. Oman, G. Stenchikov and A. B. Marquardt, 2009, Sulfuric acid deposition form
stratospheric geoengineering with sulphate aerosols, Journal of Geophysical Research – Atmospheres, 114.
Available online at http://www.stanford.edu/~bkravitz/research/papers/aciddep/aciddepositioncorrected1.pdf
44
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Species that are particularly poor at adapting to climate change, and which might therefore
benefit most from SRM deployment, are also those most at risk from sudden SRM
termination (See section 4.1.5).
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Current species and ecosystems may not be adapted to living in novel environments resulting
from global change. This is true both for a world of climate change (high temperatures,
altered precipitation patterns, increased CO2 concentrations) or from a world of climate
change masked by SRM (more diffuse light, altered precipitation patterns, high CO2
concentrations).
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Overall, if (i) the world behaves the way that it does in most climate models, (ii) there were no
secondary socio-political feedbacks to consider and (iii) there were no serious additional side
effects, then, in general, uniformly deployed SRM should significantly reduce the impacts of
climate change on biodiversity relative to a high greenhouse gas world without SRM.
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However, the climate model predictions are unlikely to reflect closely changes in the real
world, particularly at fine spatial and temporal scales (annual to decadal), and SRM
deployment would almost certainly entail secondary socio-political feedbacks, and have
unexpected side effects.
1443
4.1.4 Impacts of high CO2 under SRM
1444
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1447
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SRM does not seek to reduce the atmospheric concentrations of greenhouse gases, and the
process of ocean acidification will therefore continue unabated. Indeed, it could be
worsened139, since more CO2 will dissolve in the ocean if its surface temperature has been
reduced by SRM (relative to a non-geoengineered world). Marine biodiversity will therefore
continue to be vulnerable to the negative impacts of ocean acidification, as discussed in more
detail in Chapter 3.
1450
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Likewise, SRM will not address the effects of high CO2 concentrations on terrestrial
ecosystems, such as favouring some plant groups over others, while ecosystems that are
already water stressed may continue to be so under SRM.
1453
As such, SRM cannot be seen as an alternative to limiting greenhouse gas concentrations.
1454
4.1.5 Rate of environmental change and the termination effect
1455
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It is not just the magnitude, nature and distribution of environmental changes (from climate
change or from solar geo-engineering) that will affect biodiversity and ecosystem services,
but also the rate at which the changes take place. In general, the faster an environment
changes, the greater the risk to species140. SRM, if effective, could slow, halt or even reverse
the pace of global warming much more quickly than emissions cuts (instantly versus decades
or longer), notwithstanding potential side effects. Therefore, it could either be deployed at
short order in order to counter imminent threats, or more gradually to shave she peaks off
more extreme warming, in order to allow more time for species to adapt141.
1463
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However, in addition to the biological and ecological impacts of SRM identified above, there
is an additional issue to consider when evaluating the general effects of all SRM techniques
on biodiversity and ecosystem services: the so-called ‘termination effect’.
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SRM would only offset global warming so long as it is maintained. The cessation of SRM
would result in increased rates of climatic changes, in the absence of effective reductions of
139
Turley C & Williamson P. 2012. Ocean acidification in a geoengineering context. Phil. Trans. Roy. Soc A. (in
press)
140
Luis-Miguel Chevin, Russell Lande and Georgina Mace, 2010, Adaptation, plasticity, and extinction in a
changing environment: towards a predictive theory, PLoS Biology, 8 (4): e1000357.
doi:10.1371/journal.pbio.1000357
141 Secretariat of the Convention on Biological Diversity (2009) Connecting Biodiversity and Climate Change
Mitigation and Adaptation: Report of the Second Ad Hoc Technical Expert Group on Biodiversity and Climate
Change. Technical Series No.41. CBD, Montreal, 126 pp
45
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atmospheric greenhouse gas concentrations: all the warming that would have taken place over
several decades might take place over a shorter period.
1470
1471
1472
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Rapid termination of SRM that had been deployed for some time, and was masking a high
degree of warming, would almost certainly have large negative impacts on biodiversity and
ecosystem services that would be more severe than those resulting from gradual climate
change. SRM does not address the problem of ocean acidification because it does not address
CO2 concentrations.
1475
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Without any opportunity for species and communities to adapt, many microbial organisms,
plants, animals and their interactions could be affected: current rates of anthropogenic climate
change are already altering, or are projected to alter, community structure142, biogeochemical
cycles143, and fire risk144. Very rapid warming from SRM termination could lead to similar
problems.
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4.2 Potential impacts on biodiversity of specific SRM techniques.
1482
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Thus far, this chapter has only addressed the very general effects on biodiversity that uniform
dimming from SRM might have, which may not be achievable in practice. Now, the chapter
looks at the potential benefits and drawbacks associated with three specific SRM techniques –
stratospheric aerosol injection, cloud brightening and surface albedo enhancement – since
these are the options most frequently proposed. The positive and negative impacts of spacebased mirrors are expected to be similar to those of the generic SRM approaches described in
section 4.1.
1489
4.2.1 Potential impacts on biodiversity of stratospheric aerosol injection
1490
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In addition to the positive and negative impacts of generic SRM approaches described in
section 4.1, this proposed SRM technique could affect atmospheric acidity, stratospheric
ozone depletion, and the overall quantity and quality of light reaching the biosphere, with
knock-on effects on biodiversity and ecosystem services. It is worth noting that any projected
effects on biodiversity associated with atmospheric acidity and ozone depletion/UV radiation
would not necessarily occur if aerosols other than sulphates were to be used for this SRM
technique. However, other particles that have been suggested145, including nano-materials,
might bring with them their own particular risks.
1498
Increased acidity in the atmosphere
1499
1500
1501
1502
1503
Use of sulphate aerosols would marginally increase the negative effects of atmospheric
acidity, such as acid rain, with consequent impacts on ecosystems. However, the size of this
effect might not be very large because the suggested quantities of sulphur required for this
form of SRM would likely be less than 10% of the global deposition, and possibly as little as
1%146.
1504
Ozone depletion and increased UV radiation
1505
1506
One proposed method of stratospheric aerosol injection would involve spraying sulphur
dioxide to create sulphate aerosols. There is some evidence that an increase in sulphate levels
142
G. Walther et al (2002) Ecological responses to recent climate change. Nature, 416: 389-395.
R.G. Zepp, T.V. Callaghan and D.J. Erickson III (2003) Interactive effects of ozone depletion and climate
change on biogeochemical cycles. Photochem. Photobiol. Sci., 5: 51-61.
144 J. Pinol, J. Terradas and F. Lloret (1998) Climate warming, wildfire hazard, and wildfire occurrence in coastal
Eastern Spain. Climatic Change, 38: 345-357.
145 Keith, D.W. (2010). Photophoretic levitation of engineered aerosols for geoengineering. PNAS September 21,
2010 vol. 107 no. 38 16428-16431
146 Kravitz, B., Robock, A., Oman, L., Stenchikov, G., & Marquardt, A. B. (2009). Sulfuric acid deposition from
stratospheric geoengineering with sulfate aerosols. Journal of Geophysical Research-Atmospheres, 114, D14109.
143
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in the stratosphere would lead to increased ozone depletion147, primarily in polar regions in
springtime. This would, in turn, cause an increase in the amount of ultra violet (UV) radiation
reaching the Earth, which would affect some species more than others. Certain plants possess
a protective layer on the upper surface of their leaves, making them less susceptible to UV
damage. The ecological effects of increased UV radiation also depend on the percentage
change in UV radiation under stratospheric aerosol injection, and on the spectral forms (UVA,
UVB and UVC) likely to be most affected. Possibly, the increase in UV due to depleted ozone
might be partially offset by the attenuation of UV by the aerosols.
1515
1516
1517
The impact of stratospheric ozone injection on the amount of UVB radiation reaching the
Earth’s surface (with consequent impacts on biodiversity and ecosystem services) is very
difficult to predict.
1518
Changes in the nature and amount of light reaching ecosystems
1519
1520
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1522
Stratospheric aerosols would decrease the amount of photosynthetically active radiation
(PAR) reaching the Earth, but would increase the amount of diffuse (as opposed to direct)
radiation. The effects that this would have would vary from ecosystem to ecosystem, and
from species to species.
1523
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1529
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1531
For example, the net efficiency of carbon fixation by the forest canopy is increased when light
is distributed more uniformly throughout the canopy, as occurs with diffuse light. Diffuse
light penetrates the upper canopy more effectively than direct radiation because direct light
saturates upper sunlit leaves but does not reach lower leaves. It has therefore been suggested
that effects of the (small) reduction in total PAR would be less than the effects of the increase
in diffuse radiation giving a net improvement in photosynthetic efficiency, leading to
increased primary productivity in terrestrial ecosystems overall. Such may have been the case
following the Mt. Pinatubo eruption148, and during the ‘global dimming’ period (19501980)149.
1532
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1538
However, the magnitude and nature of effects on biodiversity are likely to be mixed, and are
currently not well understood. While the increase in diffuse light as a result of stratospheric
ozone injection might increase gross primary productivity (GPP) in certain ecosystems, GPP
is not necessarily a good proxy for biodiversity, and increases in GPP could be due to a few
species thriving in more diffuse light. In addition, for ecosystems where total light availability
is the major growth-limiting factor, the small decrease in total radiation could be harmful
while the increase in diffuse radiation is of no net benefit.
1539
1540
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1543
1544
1545
1546
1547
Complicating this picture is the fact that aerosol-induced cooling would probably slow the
rate of organic matter decomposition in the soil, and thus reduce the availability of nutrients
to plants. Persistent nutrient limitations may alter plant responses to diffuse light. One further
complication is that while diffuse light is better at penetrating the canopy, sunflecks (bursts of
very strong light which penetrate the canopy and reach the forest floor) would be less intense
with diffuse light as opposed to direct light150. Changes in the nature and amount of light
reaching ecosystems may therefore affect community composition and structure. Analyses of
effects of large-scale, aerosol-based SRM on marine photosynthesis have not been carried
out; however, primary production in the upper ocean is closely linked to the depth of light
147
Robock, A. Marquardt, A., Kravitz, B., and G. Stenchikov. (2009). Geophysical Research Letters, Volume 36,
L19703, Pages 1-9.
148 Gu, L., Baldocchi, D.D., Wofsy, S.C., Munger, J.W., Michalsky, J.J., Urbanski, S.P. and Boden, T.A. 2003.
Response of a deciduous forest to the Mount Pinatubo eruption: Enhanced photosynthesis. Science 299: 20352038.
149 Mercado, L. M., et al. (2009), Impact of changes in diffuse radiation on the global land carbon sink, Nature,
458, 1014-1018, doi:10.1038/nature07949.
150 F. Montagnini and C.F. Jordan (2005) Tropical Forest Ecology: The Basis for Conservation and Management.
Springer, UK.
47
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1549
penetration, that is greatest for direct sunlight151. Thus, ocean productivity could be expected
to decrease.
1550
4.2.2. Potential impacts on biodiversity of cloud brightening
1551
1552
1553
1554
1555
While section 4.1 described the positive and negative impacts of SRM approaches which
assumed uniform dimming, this proposed SRM technique does not cause uniform dimming.
Therefore it could cause stronger regional or local atmospheric and oceanic perturbations with
possibly significant effects on terrestrial and marine biodiversity and ecosystems. However,
few models are available on the impacts of cloud brightening on biodiversity.
1556
1557
Cloud brightening is expected to cause localized cooling, the magnitude and effects of which
are poorly understood.
1558
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Changes to regional precipitation regimes resulting from cloud brightening are expected to
increase overland water flow and this may have significant impacts on terrestrial
ecosystems.152 Other changes to local weather patterns may have impacts on biodiversity.
1561
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1566
The high degree of localised cooling projected as a result of cloud brightening has been
shown in some modelling studies to have knock-on effects on weather systems at different
locations around the globe153 , such as the West African Monsoon and the El Niño Southern
Oscillation. However, results are inconsistent across different studies, or are based on very
different parameters (e.g. different spray patterns) and so are not directly comparable. This
could have either positive or negative effects on biodiversity.
1567
4.2.3. Potential impacts on biodiversity of surface albedo enhancement
1568
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The specific impacts of surface albedo enhancement on biodiversity and ecosystem services,
over and above the impacts of generic SRM approaches involving uniform dimming are
described in section 4.1, depend on what method is used. Surface albedo can be increased, for
example, through whitening the built environment, use of crops with more reflective foliage,
covering deserts (or other lands) with reflective material, and use of micro-bubbles in water
bodies. The albedo of the surface ocean might be enhanced through the introduction of
microbubbles (currently called ‘Bright Water’) with claims that the microbubbles are
effective at reducing solar radiation even at parts per million levels154.
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In general, if surface albedo changes were large enough to have an effect on the global
climate, they would have to be deployed across a very large area – with consequent impacts
on ecosystems, or would involve a very high degree of localised cooling.
1579
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For instance, covering deserts with reflective material on a scale large enough to be effective
in addressing the impacts of climate change would probably have significant negative
ecological effects155, for instance on species richness and population densities.
1582
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1584
Introducing bubbles into large expanses of water bodies would probably have negative
impacts on ocean biodiversity due to decreased light penetration, with possible impacts on
currents and further knock-on impacts on local ecosystems.
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1586
Increasing crop albedo through use of crops with more reflective foliage would have
unknown effects on biodiversity and ecosystems beyond those caused by the positive or
151
Morel A. 1991. Light and marine photosynthesis: a spectral model with climatological implications. Progress in
Oceanography 26, 263-306
152
Bala, G., Caldeira, K., Nemani, R., Cao, L., Ban-Weiss, G. and Ho-Jeong Shin. (2010). Albedo enhancement of
marine clouds to counteract global warming: impacts on hydrological cycle. Climate Dynamics, Online First.
153
Jones et al, 2009; Latham et al, 2008, Rasch et al, 2009
154
Seitz R (2011) Bright water: hydrosols, water conservation and climate change. Climatic Change.
doi:10.1007/s10584-010-9965-8
155 The Royal Society (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
48
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negative impacts of localised cooling. However, if deployed very widely, this approach could
result in increased monoculture.
1589
1590
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1592
Whitening the built environment would likely have no specific effects on biodiversity and
ecosystems beyond those caused by the positive or negative impacts of localised cooling.
While the total cooling effect would be moderate at best, local cooling of buildings may
reduce energy use for air conditioning.
1593
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The effects of local cooling are poorly understood. While a high degree of localised cooling
might help local ecosystems that are being damaged by the effects of climate change, the
‘patchy’ nature of the cooling might change local systems more than the global warming that
the schemes are seeking to address.156
1597
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156
For example, add reference to recent study on unclear results on urban albedo.
49
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1600
CHAPTER 5: POTENTIAL IMPACTS ON BIODIVERSITY OF CARBON DIOXIDE
REMOVAL GEO-ENGINEERING TECHNIQUES
1601
1602
5.1. General features of CDR approaches
1603
5.1.1 Reducing the impacts of climate change
1604
1605
1606
By removing Carbon Dioxide (CO2) from the atmosphere, CDR techniques are intended to
reduce the concentration of the main causal agent of climate change and ameliorate ocean
acidification.
1607
1608
1609
1610
1611
By reducing the negative impacts of climate change and ocean acidification on biodiversity,
(as summarised in Chapter 5) effective and feasible CDR techniques would be expected to
have positive impacts on biodiversity. However, as noted in Chapter 2, these effects are
generally slow acting. Moreover, several of the techniques are of doubtful effectiveness as
described in section 5.2.
1612
1613
1614
1615
In addition, any positive effects from reduced impacts of climate change and/or ocean
acidification due to reduced atmospheric CO2 concentrations may be offset (or, in a few cases,
augmented) by the direct impacts on biodiversity of the particular CDR technique employed.
These are reviewed in section 5.2.
1616
5.1.2 Sequestration and storage
1617
Carbon Dioxide Removal (CDR) geo-engineering approaches actually involve two steps:
1618
(1) carbon sequestration or removal of CO2 from the atmosphere; and
1619
(2) storage of the sequestered carbon.
1620
1621
1622
1623
In some biologically- and chemically-driven processes these steps occur together or are
inseparable. This is the case in ocean fertilization techniques and in the case of afforestation,
reforestation and soil carbon enhancement. In these cases, the whole process, and their
impacts on biodiversity, are confined to marine and terrestrial systems respectively.
1624
1625
1626
1627
1628
1629
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1631
1632
1633
In other cases, the steps are discrete, and various combinations of sequestration and storage
options are possible. Carbon sequestered as biomass, for example, could be either: dumped in
the ocean as crop residues; incorporated into the soil as charcoal; or used as fuel with the
resultant CO2 sequestered at source and stored either in sub-surface reservoirs or the deep
ocean. In these cases, each step will have different and additive potential impacts on
biodiversity and both need to be examined. In some of these cases, there will be separate
impacts on marine and terrestrial environments. In the case of enhanced weathering also,
there will be the impacts of mining of rocks and transport in terrestrial environments as well
as proximate impacts in the ocean and/or on the land due to the geo-chemical impacts of the
measure.
1634
5.1.3 Impact on ocean acidification
1635
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1637
While sequestration of CO2 from the atmosphere will reduce ocean acidification, this benefit
may be compromised if, for example, the CO2 leaks into the ocean from geological storage
sites or as a result of decomposition of ocean stored biomass.
50
1638
Table 5.1: Classification of CDR techniques and summary of impacts157
Technique(s)
Location of side
effects other than
CO2 removal
Capture
Amelio
rates
OA?
Nature of side effects on biodiversity other than CO2 removal
Changes to phytoplankton productivity & diversity, food-webs and
biogeochemical cycling; anoxia; acidification in deep sea
Storage
1. Ocean
Fertilization
direct external fertilization
– Ocean –
x(√?)
up/downwelling modification
– Ocean –
x(√?)
2. Enhanced
weathering
Ocean alkalinity (ocean)
– Ocean+ –
√
Spreading of base minerals
– Land+ –
√
3. Terrestrial
Ecosystem
management
Afforestation
– Land –
√
Negative and positive impacts of land use change
Reforestation
– Land –
√
Generally positive impacts on forest ecosystems
Soil carbon enhancement
– Land –
√
Mostly positive impacts of soil carbon enhancements
4. Biomass
Biomass Production
Land
Na
Biofuels with CCS
na
Sub-S
√
above + estimated small risk of leakage
Charcoal storage
Land
√
above + mostly benign but uncertain impacts on soil condition
Ocean biomass storage
Ocean
5. Air Capture
6. CO2 Storage
Habitat destruction from mining and transportation on land; localized
impacts of excess alkalinity at sea
Ocean CO2 storage
Habitat change; carbon debt
X (√?)
above + damage to benthic environments; eutrophication
Either
Na
√
Minor land cover changes; water use; energy use
na
Ocean
X
Damage to deep sea ecosystems; ocean acidification
Sub-S
√
Estimated small risk of leakage
Geological CO2 reservoirs
1639
157
Refer to Table 2.2 for information on likely effectiveness of the technologies
+
Ocean alkalinity: will also have indirect impacts on land through mining and transport of materials.
+
Spreading of alkaline minerals: will eventually have impacts (largely positive) on oceans through run-off to oceans.
(√?) indicates possible small effect on ameliorating Ocean Acidification (OA)
51
1640
5.1.4 Land and ocean-based approaches and potentially vulnerable biodiversity
1641
1642
As noted above, and summarised in Table 5.1, some CDR approaches will impact terrestrial
ecosystems, some marine systems and some both.
1643
Ocean-based approaches and potentially vulnerable marine biodiversity
1644
1645
1646
1647
The impacts of ocean-based CDR will vary greatly according to techniques. Whilst one
approach – ocean iron fertilization – has been relatively well investigated through small-scale
experiments and models (with several reviews158,159), most other interventions remain
theoretical.
1648
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1650
The behaviour of marine ecosystems subject to perturbations is inherently difficult to model
and predict due to the complex interactions between marine physical, chemical and biological
processes, operating over a wide range of spatial and temporal scales.
1651
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Deep sea multicellular organisms have adapted to the energy-limited environment of the deep
sea by limiting investment in reproduction, thus most deep-sea species produce few offspring.
Deep-sea species tend to invest heavily in each of their eggs, making them large and rich in
yolk to provide the offspring with the resources they will need for survival.160Due to their
generally low metabolic rates, deep-sea fauna tend to grow slowly and have much longer
lifespans than their upper-ocean cousins. For example, on the deep-sea floor, a bivalve less
than 1 cm across can be more than 100 years old161. This means that populations of deep-sea
species will be more greatly affected by the loss of individual larvae than would upper ocean
species. Upon disturbance, recolonization and community recovery in the deep ocean follows
similar patterns to those in shallow waters, but on much longer time scales (several years
compared to weeks or months in shallow waters)162.
1662
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The deep sea and its sediments also contain high abundances of microbes (bacteria, archaea
and protists) for which there is very little information available.
1664
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1667
1668
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The numbers of non-microbial organisms living on the sea floor per unit area decreases
exponentially with depth, probably associated with the diminishing flux of food with depth.
On the sea floor of the deepest ocean and of the upper ocean, the fauna can be dominated by a
few species. Between 2000 and 3000 m depth, ecosystems tend to have high species diversity,
not counting the species present in the water column, with a low number of individuals,
meaning that each species has a low population size163. The fauna living in the water column
appear to be less diverse than that on the sea floor, probably due to the relative uniformity of
vast volumes of water in the deep ocean.
1672
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Most experimental studies on CO2 (and pH) sensitivity of benthic and sediment-dwelling
organisms have been carried on shallow-water species164 and, in fact, our knowledge of the
158
Secretariat of the Convention on Biological Diversity (2009). Scientific Synthesis of the Impacts of Ocean
Fertilization on Marine Biodiversity. Technical Series No. 45. CBD, Montreal, 53 pp
159 Wallace DWR, Law CS, Boyd PW, Collos Y, Croot P, Denman K, Lam PJ, Riebesell U, Takeda S and
Williamson P. (2010) Ocean fertilization: A scientific summary for policy makers. IOC/UNESCO, Paris
(IOC/BRO/2010/2)
160 IPCC (2005a) IPCC Special Report on Carbon Capture and Storage, Summary Report for Policy Makers, 25
pp.
161 Gage JD and Tyler PA (1991) Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor.
Cambridge University Press, Cambridge, 504 pp.
162 Smith CR and Demopoulos AW (2003) Ecology of the deep Pacific Ocean floor. In ‘Ecosystems of the Deep
Ocean’, PA Tyler (Ed) Elsevier, Amsterdam, pp. 179-218.
163 Snelgrove PVR and Smith CR (2002) A riot of species in an environmental calm: The paradox of the species
rich deep-sea floor. Oceanography and Marine Biology, An Annual Review 40, 311-342; IPCC (2005a) IPCC
Special Report on Carbon Dioxide Capture and Storage, Summary Report for Policy Makers, 25 pp.
164 Andersson A.J., Mackenzie, F.T. & Gattuso, J.-P. (2011) Effects of ocean acidification on benthic processes,
organisms and ecosystems. In: Ocean Acidification (Eds: J.-P. Gattuso & L. Hansson). Oxford University Press, p
122-153
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deep sea is still very limited with new species being discovered regularly165. Whilst coldwater corals currently living close to carbonate saturation horizons (2000m in the North
Atlantic; 50-600m in the North Pacific) are likely to be especially vulnerable to CDRenhanced deepwater pH changes, species living at greater water depths already experience
relatively low pH (< 7.4, cf ~8.1 in the upper ocean)166, that will vary according to episodic
inputs of organic material from the upper ocean167. Within sediments, pH can vary by more
than 1.7 units within the top few millimetres or centimetres168, with sub-surface values being
relatively insensitive to changes in the overlying seawater.
1682
Land-based approaches and potentially vulnerable terrestrial biodiversity
1683
1684
1685
1686
1687
Land-based CDR potentially covers a range of proposals, although (as noted in Chapter 2)
there is currently disagreement as to whether processes such as bio-energy carbon capture and
storage and changes in forest cover and land use should be considered as geo-engineering. In
many cases, they replicate natural processes or reverse past anthropogenic changes to land
and land use.
1688
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1690
1691
1692
1693
1694
1695
1696
1697
The level of information concerning some land-based CDR approaches (as broadly defined
here) is relatively well-developed. For example, reforestation and restoration activities reverse
previous human-induced land-use changes, and the implications of these activities on
biodiversity, ecosystem services, surface albedo and local and regional hydrological cycles
are reasonably well known. While there have been site-based assessments to measure the
impacts of biochar on crop yield, nutrient cycles, water availability and other factors169, so far,
no clear conclusions can be drawn. These studies do not necessarily equate to effectiveness
and safety if such approaches are applied as geo-engineering interventions, since in some
cases the scale of such interventions in order to affect climate change would be far greater
than what has been studied thus far.
1698
1699
1700
1701
1702
1703
1704
Because of the range of techniques that can be included under land-based CDR, it is difficult
to identify ecosystems and species which will be most vulnerable to possible negative
impacts. In discussions on biofuel production, however, Parties to the CBD identified a
number of vulnerable components of biodiversity that should be considered in order to avoid
significant negative impacts. These include: primary forests with native species; rare,
endangered, threatened and endemic species, high biodiversity grasslands and peatlands and
other wetlands170.
1705
1706
1707
1708
5.2. Projected impacts on biodiversity of individual Carbon Dioxide Removal
approaches
1709
5.2.1 Ocean Fertilization techniques
1710
1711
1712
Ocean fertilization involves the addition of nutrients to the marine environment with the aim
of enhancing the uptake of CO2 in the oceans through biological processes and the subsequent
sequestration (long-term storage) of a portion of the additional organic carbon in the deep sea.
165
Hotspot Ecosystem Research on the Margins of European Seas (HERMES). List of publications.
http://www.eu-hermes.net/publications_public.html
166 Joint, I., Doney, S.C. & Karl, D.M. 2011 Will ocean acidification affect marine microbes? The ISME Journal
5, 1-7.
167 Gooday, A.J. (2002) Biological responses to seasonally varying fluxes of organic matter to the ocean floor: A
review. J. Oceanography, 58, 305-332.
168 Widdicombe, S., Spicer, J.I. & Kitidis, V. (2011) Effects of ocean acidification on sediment fauna. In: Ocean
Acidification (Eds: J.-P. Gattuso & L. Hansson). Oxford University Press, p 176-191.
169 Major J, Rondon M, Molina D, Riha S and Lehmann J, (2010). Maize yield and nutrition during 4 years after
biochar application to a Colombian savanna oxisol. Plant and Soil, Volume 333, Pages 117-128.
170 Secretariat of the Convention on Biological Diversity. Report of the Regional Workshop for Asia and the
Pacific on Ways and Means to Promote the Sustainable Production and Use of Biofuels. 2009
53
1713
1714
This may be achieved through the external addition of nutrients or by modifying ocean
upwelling and downwelling (section 5.2.1.2).
1715
5.2.1.1 Direct external ocean fertilization techniques
1716
1717
1718
1719
1720
This section considers direct ocean fertilization by adding external nutrients. Most attention
has been given to iron, an element lacking in some ocean areas (primarily the Southern Ocean
and equatorial Pacific), yet only required in small quantities as a micro-nutrient by marine
organisms. Other approaches include manipulations to increase the internal (re-)supply of
macro-nutrients such as nitrogen and phosphorus.
1721
1722
1723
1724
1725
1726
1727
1728
There have been 13 field experiments on ocean fertilization over the last 20 years, at the scale
of 50-500 km2. Although not designed for geo-engineering purposes, these studies have
addressed some of the uncertainties concerning the impacts of ocean fertilization on
biodiversity171. The limited experiments conducted to date indicate that this is a technique of
doubtful effectiveness, since much of the enhanced carbon uptake is returned to the
atmosphere relatively rapidly rather than being sequestered in the deep ocean. The technical
feasibility and the costs of monitoring and verification of long-term sequestration seem likely
to be very high.
1729
Changes in phytoplankton community structure and diversity and food webs
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For ocean fertilization technique to work, biological primary production (photosynthesis by
algae and bacteria) will increase, inevitably involving changes in phytoplankton community
structure and diversity172,173, with implications for the wider food-web. Whilst the duration of
those changes will depend on the fertilization method and treatment frequency, the desired
outcome would be to closely mimic or enhance natural phytoplankton blooms.
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More permanent changes are however likely if ocean fertilization is sustained, and carried out
on a climatically-significant scale. Such changes may include an increased risk of harmful
algal blooms, involving increased toxic diatoms174,175. In addition, if the supply of organic
matter to deep sea sediments were significantly enhanced, that would lead to greater densities
and biomass of benthos176.
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Iron-induced increases in marine productivity and carbon uptake will only occur in those
ocean regions where iron is currently lacking yet macro-nutrients are abundant, primarily the
Southern Ocean and equatorial Pacific. However, increases in net primary productivity in
these regions will be offset by decreases in adjacent areas (Figure 5.1) due to use of macronutrients as part of the fertilization process177.
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Fish stocks can be expected to generally increase in response to increased phytoplankton (and
zooplankton) arising from ocean fertilization. However, they could also decrease in far field
171
Secretariat of the Convention on Biological Diversity (2009). Scientific Synthesis of the Impacts of Ocean
Fertilization on Marine Biodiversity. Technical Series No. 45. CBD, Montreal, 53 pp.
Wallace DWR, Law CS, Boyd PW, Collos Y, Croot P, Denman K, Lam PJ, Riebesell U, Takeda S and Williamson
P. (2010) Ocean fertilization: A scientific summary for policy makers. IOC/UNESCO, Paris (IOC/BRO/2010/2)
172 Boyd PW, Jickells T, Law CS, Blain S and others (2007) Mesoscale iron enrichment experiments 1993-2005:
synthesis and future directions. Science 315, 612–617
173 Boyd PW, Law CS, Wong CS, Nojiri Y and others (2004) The decline and fate of an iron-induced subarctic
phytoplankton bloom. Nature 428, 549–553
174 Trick CG, et al. (2010) Iron enrichment stimulates toxic diatom production in high-nitrate, low-chlorophyll
areas. Proc Natl Acad Sci USA 107, 5887–5892.
175 Silver MW, Bargu S, Coale SL, Benitez-Nelson CR, Garcia AC, Roberts KJ, Sekula-Wood E, Bruland KW and
Coale KH (2010) Toxic diatoms and domoic acid in natural and iron enriched waters of the oceanic Pacific. Proc
Natl Acad Sci USA 107, 20762-20767.
176 Wolff GA, Billett DSM, Bett BJ, Holtvoeth J, FitzGeorge-Balfour T, mFisher EH, Cross I, Shannon R, Salter I,
Boorman B, King NJ, Jamieson A and Chaillan F (2011) The effects of natural iron fertilisation on deep-se
ecology: The Crozet Plateau, Southern Indian Ocean. PLoS ONE 6(6) e20697 doi:10.1371/journal.pone.0020697.
177 Gnanadesikan A, Marinov (2008) Export is not enough: nutrient cycling and carbon sequestration. Mar Ecol
Prog Ser 364:289–294
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areas where primary production is reduced (Figure 5.1), and in response to altered water
quality (increased anoxic zones and lower pH) in mid and deep water.
1749
Ocean acidification
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Although ocean fertilization may slow near-surface ocean acidification, it would increase
acidification of the deep ocean178.
1752
Figure 5.1. Changes in primary production after 100 years of global iron fertilization179
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Projected increases (red, orange and yellow) and decreases (blue) in vertically integrated
primary productivity (gC/m2/yr) after 100 years of global iron fertilization.
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Changes in biogeochemical cycling
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Ocean fertilization is expected to increase biogeochemical cycling in surface layers (including
CO2 uptake and trace gas production) although the extent of long term CO2 drawdown is
likely to be variable and difficult to quantify. This increase in biogeochemical cycling is
expected to accelerate and enhance the remineralisation of sinking particles with an associated
potential production of methane (CH4) and nitrous oxide (N2O)180. If released in any quantity
to the atmosphere, these greenhouse gases could significantly reduce the effectiveness of
ocean fertilization as a geo-engineering technique. Whilst enhanced dimethyl sulfide (DMS)
emissions from plankton could be considered a ‘beneficial’, unintended outcome of ocean
fertilization, due to albedo effects, the scale (and even sign) of this response is uncertain, and
the overall linkage between DMS and climate is now considered relatively weak.
1768
5.2.1.2 Ocean fertilization through modification of upwelling and downwelling
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Artificial upwelling is an ocean fertilisation technique that brings cool, deep water (~200 –
1000 m) rich in nutrients up to the surface, for example through some type of pipe, to fertilise
the phytoplankton181. There have been some field experiments carried out in the Pacific
Ocean182, 183.
178
Cao, L., and K. Caldeira (2010) Can ocean iron fertilization mitigate ocean acidification? Climatic Change,
99(1-2): 303-311
179 Aumont O. & Bopp L. 2006. Globalizing results from ocean in situ iron fertilization studies. Global
Biogeochemical Cycles, 20, GB2017, doi: 10.1029/2005GB002591
180 Law CS (2008) Predicting and monitoring the effects of large scale ocean iron fertilization on marine trace gas
emissions. Marine Ecology Progress Series 364, 283-288.
181 Lovelock JE and Rapley CG (2007) Ocean pipes could help the Earth to cure itself. Nature 449, 403.
182 Maruyama S, Yabuki T, Sato T, Tsubaki K, Komiya A, Watanabe M, Kawamura H and Tsukamoto K. (2011)
Evidences of increasing primary production in the ocean by Stommel’s perpetual salt fountain. Deep-Sea Research
I, 58, 567-574.
55
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The intended effects of artificial upwelling to stimulate phytoplankton growth and carbon
uptake are essentially the same as for ocean fertilization above (section 5.2.1.1) and
consequently will not be repeated here. However, there is a major problem with the concept,
as the nutrient rich water brought up to the surface also contains high concentrations of
dissolved CO2 derived from the degradation of organic material. The release of this CO2 to
the atmosphere184, 185 would counteract most (if not all) of the potential climatic benefits from
the fertilization of the plankton.
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Upwelling in one area necessarily also involves downwelling elsewhere. Modifying
downwelling currents to carry increased carbon into the deep ocean by either increasing the
carbon content of existing downwelling or by increasing the volume of downwelling water
has also been considered.
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While the view of some authors186 is that “modifying downwelling currents is highly unlikely
to ever be a cost-effective method of sequestering carbon in the deep ocean”, lower-cost
structural approaches have recently been proposed.187 In order to estimate the number of such
structures necessary to achieve global climate impact, the hydrodynamics and
biogeochemistry of such systems would need further attention. However, it is likely to be
high, covering a significant proportion of the ocean surface, since – as for other ocean
fertilization techniques188 – the geo-engineering requirement is for long-term sequestration of
anthropogenic carbon, not carbon uptake per se. In particular: i) if the increased
phytoplankton growth is stimulated by nutrients from deeper water, such water will also
contain higher CO2, thus no drawdown of atmospheric CO2 will be achieved; ii) there is
considerable variability in the timescale of carbon re-cycling in the ocean interior,
determining the rate of return of additional, biologically-fixed CO2 to the atmosphere and iii)
enhancement of biological production at the scale required for climatic benefits is likely to
significantly deplete mid-water oxygen, resulting in increased CH4 and N2O release. High
costs are therefore likely to be involved in achieving reliable data on long term carbon
removal (needed for international recognition of the effectiveness of the intervention), also in
quantifying potentially counter-active negative impacts, over large areas (ocean basin scale)
and long time periods (10-100 years).
1802
5.2.2. Geo-chemical sequestration of carbon dioxide
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Carbon dioxide is naturally removed from the atmosphere by the weathering (dissolution) of
carbonate and silicate rocks. However, the process of natural weathering is incredibly slow:
CO2 is consumed at around one hundredth of the rate at which it is currently being emitted189.
It has therefore been proposed that, in order to constitute a significant means of combating
climate change, the natural process of weathering could be artificially accelerated. There is a
range of proposed techniques that include releasing calcium carbonate or other dissolution
183
White A, Bjorkman K, Grabowski E, Letelier R, Poulos S, Watkins B and Karl D (2010) An open ocean trial of
controlled upwelling using wave pump technology. Journal of Atmospheric and Oceanic Technology 27 (2) 385396.
184 Oschlies A, Pahlow M, Yool A and Matear RJ (2010) Climate engineering by artificial ocean upwelling:
Channelling the sorcerer’s apprentice. Geophysical research Letters 37, L04701.
185 Yool A, Shepherd JG, Bryden HL & Oschlies A (2009). Low efficiency of nutrient translocation for enhancing
oceanic uptake of carbon dioxide. Journal of Geophysical Research doi: 10.1029/2008JC004837.
186 Zhou S and Flynn PC (2005) Geoengineering downwelling ocean currents: A cost assessment. Climatic Change
71 (1-2) 203-220.
187 Salter S.H. (2009) A 20GW thermal 300-metre3/sec wave-energised, surge-mode nutrient-pump for removing
atmospheric carbon dioxide, increasing fish stocks and suppressing hurricanes. Proceedings of the 8 th European
Wave and Tidal Energy Conference, Uppsala, Sweden, 2009; p 1- 6.
188 Wallace DWR, Law CS, Boyd PW, Collos Y, Croot P, Denman K, Lam PJ, Riebesell U, Takeda S and
Williamson P. (2010) Ocean fertilization: A scientific summary for policy makers. IOC/UNESCO, Paris
(IOC/BRO/2010/2)
189 IPCC (2005) Special Report on Carbon Dioxide Capture and Storage. Prepared by Working Group III of the
Intergovernmental Panel on Climate Change. J.T. Houghton, Y. Ding, D.J. Griggs, M. Nouger, P.J. van der Linden
and D. Xiaosu (eds). Cambridge University Press, Cambridge.
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products of alkaline minerals into the ocean (section 5.2.2.1) or spreading abundant silicate
minerals such as olivine over agricultural soils (section 5.2.2.2).
1811
5.2.2.1. Enhanced ocean alkalinity
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This proposed approach is based on adding the dissolution products of alkaline minerals (e.g.
calcium carbonate and calcium hydroxide) in order to chemically enhance ocean storage of
CO2; it also would buffer the ocean to decreasing pH, and thereby help to counter ocean
acidification190.
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Dissolution products of alkaline minerals could be released into the ocean through a range of
proposed techniques: CO2-rich gases dissolved in sea water to produce a carbonic acid
solution that is then reacted with a carbonate mineral to form calcium and bicarbonate ions191,
192,193
; bicarbonate ions from the electrochemical splitting of calcium carbonate (limestone) 194;
or magnesium and calcium chloride salts from hydrogen and chlorine ions produced from the
electrolysis of sea water to form hydrochloric acid which is then reacted with silicate rocks195.
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Each of these techniques involve relatively large volumes, and operational proposals therefore
envisage the addition of material through a pipeline into the sea or indirectly through
discharge into a river. This limits the application of these techniques to coastal zones, thereby
limiting the potential for rapid dilution and increasing the local impacts on ecosystems.
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Other proposals involve the direct addition of limestone powder196 or calcium hydroxide197 to
the ocean.
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These latter approaches can introduce their material from ships which not only increases
flexibility with the sites of application but also can achieve much higher dilution rates to
minimise any short-term pH spikes.
1831
Impacts of local excess alkalinity on marine biodiversity
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1834
While the chemistry of the processes of enhancing ocean alkalinity is well understood, the
impacts on biodiversity are not. In particular, the effects of enhanced Ca2+ ions and dissolved
inorganic carbon on biodiversity are not known adequately.
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It is expected that the initial local spatial and temporal pH spike could be harmful to
biodiversity; however, this impact is transient and can be minimised through rapid dilution
and dispersion and in the case of particulate material, by controlling the dissolution rate of the
substance through its particle size.
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The state of knowledge is limited but impacts on ecosystem services are likely if the
technique is carried out in continental shelf waters.
190
Kheshgi H (1995)Sequestering atmospheric carbon dioxide by increasing ocean alkalinity. Energy 20 (9) 915922.
191 Rau GH and Caldeira K (1999) Enhanced carbonate dissolution: a means of sequestering waste CO as ocean
2
bicarbonate. Energy Conversion and Management 40, 1803-1813.
192 Caldeira K and Rau GH (2000) Accelerating carbonate dissolution to sequester carbon dioxide in the ocean:
Geochemical implications. Geophysical Research Letters 27 (2) 225-228.
193 Rau GH (2011) Co2 mitigation via capture and chemical conversion in seawater. Environmental Science and
Technology 45, 1088-1092.
194 Rau GH (2008) Electrochemical splitting of calcium carbonate to increase solution alkalinity: Implications for
carbon dioxide and ocean acidity. Environmental Science and Technology 42, 8935-8940.
195 House KZ, House CH, Schrag DP and Aziz MJ (2007) Electrochemical acceleration of chemical weathering as
an energetically feasible approach to mitigating anthropogenic climate change. Environmental Science and
Technology 41, 8464-8470.
196 Harvey LDD (2008) Mitigating the atmospheric CO increase and ocean acidification by adding limestone
2
powder to upwelling regions. Journal of Geophysical Research 113, C04028, doi: 10.1029/2007JC004373
197 Cquestrate (http://www.cquestrate.com/)
57
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There are large unknowns associated with enhanced ocean alkalinity due to limited
knowledge of biological impacts. In particular, no field experiments have been carried out and
there are a limited number of theoretical papers available.
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It is questionable whether any of the approaches above can be scaled-up sufficiently to make
a difference to the global carbon budget without creating environmental impacts (both on land
and at sea) due to the bulk of materials198 that would need to be involved. Although the
quantities involved are large, enhancing ocean alkalinity using the dissolution products of
silicate rocks, for instance, would sequester two CO2 molecules in the ocean for each silicate
molecule mined. This compares favourably with the bulk of materials required for enhanced
weathering techniques on land (see section 5.2.2.2), in which only one CO2 molecule would
be consumed (and stored as a solid mineral) for each silicate molecule weathered.
1852
5.2.2.2. Enhanced weathering of carbonate and silicate rocks
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It has been proposed that the natural process of weathering could be artificially accelerated,
for instance by reacting silicate rocks with CO2 to form solid carbonate and silicate minerals.
One proposed method is to spread abundant silicate minerals such as olivine over agricultural
soils199. It is estimated that a yearly volume of 7 km3 of such minerals (roughly twice the
current rate of coal mining) would remove as much CO2 as we are currently emitting200.
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Even if weathering reactions, such as those described above, were to initially take place in
soils, the resultant chemicals would eventually be washed into the oceans. The impacts on
biodiversity (many of them unknown) of increased concentrations of bicarbonate, calcium and
magnesium ions, and hence enhanced ocean alkalinity, are outlined in section 5.2.2.1 and so
are not repeated here.
1863
Impacts on terrestrial biodiversity
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The addition of rock dust to nutrient-deficient soils may increase the productivity of those
soils, thereby reducing the incentive to convert previously non-agricultural land into
agricultural land. However, in order to have a significant effect on the Earth’s climate, most
enhanced weathering proposals would entail large-scale mining and transportation
activities201, thus potentially exacerbating habitat degradation and loss which is already
threatening numerous species.
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Enhanced weathering techniques such as spreading olivine over fields would increase soil pH,
with likely knock-on effects on vegetation and river ecosystems, and ultimately (as already
discussed) on ocean biochemistry, as a result of terrestrial reaction products reaching the sea.
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Despite confidence in the basic chemical ability of enhanced weathering to reduce
atmospheric CO2 concentrations, research into the potential impacts of this geo-engineering
technique on biodiversity and ecosystem services is currently severely limited. It is also
unknown at present what impact the large-scale dispersal of rock dust might have on
planetary albedo.
1878
5.2.3. Restoration, afforestation, reforestation, and the enhancement of soil carbon
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Although not always viewed as geo-engineering per se, familiar methods such as
afforestation, reforestation, and the enhancement of soil carbon can play a small but
199
Schuiling and Krijgsman (2006) Enhanced weathering: an effective and cheap tool to sequester CO2. Climate
Change, 74: 349-354.
200 The Royal Society (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
201 The Royal Society (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
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significant role in moderating climate change202 through increasing carbon sequestration in
natural and managed ecosystems (forests, plantations and agricultural lands).
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Afforestation involves the direct and intentional conversion of land that has not been forested
(for at least 50 years, for the purposes of the first commitment period of the Kyoto Protocol)
into forested land, through planting, seeding and/or the promotion of natural seed sources by
humans. Reforestation involves similar techniques, but is carried out on land that was
previously forested but converted to non-forested land at a certain point in time (before 31
December 1989, for the purposes of the first commitment period of the Kyoto Protocol).
Since both afforestation and reforestation result in increased forest cover, their potential
impacts on biodiversity and ecosystem services are discussed collectively below. Restoration
of some other ecosystems (marine as well as terrestrial), while making significant
contributions to biodiversity, may also make additional though smaller contributions to
reducing atmospheric CO2.
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A related means of ecosystem carbon storage is the enhancement of soil carbon. This is
achieved by improving land management practices; for instance, preventing captured CO 2
from reaching the atmosphere, and altering livestock grazing patterns so as to increase root
mass in the soil.
1898
Impacts on biodiversity
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1911
The impacts on biodiversity of ecosystem carbon storage depend on the method and scale of
implementation. If managed well, this approach has the potential to increase or maintain
biodiversity. However, if not managed well, it may result in the reduction of the distribution
of certain biomes, the introduction of invasive alien species and the conversion of land use
(e.g. from grassland to forest) and subsequent loss of species. Since afforestation,
reforestation and land use change are already being promoted as climate change mitigation
options, much guidance has already been developed. For example, the CBD has developed
guidance to maximize the benefits of these approaches to biodiversity, such as the use of
assemblages of native species and to minimize the disadvantages and risks203,204,205 such as the
use of monocultures and potentially invasive species . The CBD is also developing advice for
the application of REDD+ biodiversity safeguards (reducing emissions from deforestation and
forest degradation and the role of conservation, sustainable management of forests and
enhancement of forest carbon stocks in developing countries).
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1918
In order to maximize biodiversity benefits, ecosystem storage should be based on an
environmental impact assessment including impacts related to biodiversity and native species.
Interventions should also incorporate resilience to anticipated climate change, and should
prioritize climatically-appropriate native assemblages of species. Where such
recommendations have not been heeded (e.g. in reforestation projects using non-native
eucalyptus in Madagascar), the result has often been monoculture plantations which are
unable to support viable population of endemic species206.
1919
Impacts on ecosystem services
202
The Royal Society (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
203 Secretariat of the Convention on Biological Diversity. 2009. Connecting Biodiversity and Climate Change
Mitigation and Adaptation. Report of the Second Ad Hoc Technical Expert Group on Biodiversity and Climate
Change. Montreal, Technical Series No. 41, 126 pages.
204 Secretariat of the Convention on Biological Diversity (2003). Interlinkages between biological diversity and
climate change. Advice on the integration of biodiversity considerations into the implementation of the United
Nations Framework Convention on Climate Change and its Kyoto protocol. Montreal, SCBD, 154p. (CBD
Technical Series no. 10).
205 CBD COP decision VI/22 Annex and X/33 paragraph 8(p) –ADD additional decisions providing guidance.
206
J. Ramanamanjato and J.U. Ganzhorn (2001) Effects of forest fragmentation, introduced Rattus rattus and the
role of exotic tree plantations and secondary vegetation for the conservation of an endemic rodent and a small
lemur in littoral forests of southeastern Madagascar. Animal Conservation, 4(2): 175-183.
59
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Increased soil carbon can increase the amount of water retained in the soil, thereby increasing
the resilience of ecosystems and potentially mitigating the water-depleting effects of climate
change in arid areas. In addition, increased soil carbon has the potential to enhance crop
productivity. This may reduce the incentive to convert previously non-agricultural land into
agricultural land, and could therefore help to safeguard biodiversity/gene benefits. As
demonstrated by a watershed scale study in Oregon, USA, increasing carbon storage through
the introduction of land-use policies can be beneficial to a wide range of ecosystem
services207. Moreover, several regional studies have demonstrated that benefits to ecosystem
services such as water regulation, biodiversity conservation, and agriculture, can result from
integrated land-use planning that delivers enhanced CO2 sequestration208.
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However, it is worth noting that while increasing the amount of water retained in the soil as a
result of increased soil carbon may have positive effects in certain areas; in other areas,
increased water retention could lead to more anoxic conditions.
1933
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1937
Moreover, the potential for enhanced soil productivity could lead to adverse ecosystem
impacts since productivity would probably be enhanced to a greater extent in fast growing
species. This could lead to shifts in ecosystem composition, interactions between species, and
food webs. The potential for increased nitrogen deposition would also affect the cycling of
nutrients.
1938
Risks and uncertainties
1939
1940
1941
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1943
1944
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1946
Large-scale increases in forest cover can have an impact on both planetary albedo and the
hydrological cycle, and can create a protecting buffer for neighboring ecosystems against
floods and other environmental perturbations. Newly created forests are also likely to emit
volatile organic compounds (VOCs), which increase the concentration of cloud condensation
nuclei and therefore affect cloud formation. However, the combined effects of increased
forest cover on the hydrological cycle209, planetary albedo and cloud cover, and the knock-on
impacts on biodiversity and ecosystem services, are currently not well understood. This is an
area for which further research and assessment are required210.
1947
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1949
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1951
As for soil carbon, it will be necessary to determine whether its enhancement leads to anoxic
conditions and methane release in all instances, and if not, which types of soil carbon best
enable these adverse side effects to be avoided. It is also currently unclear how a change in
soil carbon might affect the community of species dependent on a particular area of soil, and
whether biodiversity/gene benefits would ultimately increase or decrease.
1952
5.2.4. Carbon sequestration and storage in biomass.
1953
1954
Biomass approaches to carbon dioxide removal involve two steps: biomass production
(section 5.2.4.1) and biomass storage of disposal (section 5.2.4.2).
1955
5.2.4.1. General issues on biomass production
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1957
Biomass-based approaches are based on the assumption that biomass production is either
carbon neutral or results in very low greenhouse gas emissions. However, recent work211,212
207
E. Nelson, G. Mendoza, J. Regetz, S. Polasky, H. Tallis, D.R. Cameron, K.M.A. Chan, G.C. Daily, J. Goldstein,
P.M. Kareiva, E. Lonsdorf, R. Naidoo, T.H. Ricketts and M.R. Shaw (2009) Modelling multiple ecosystem
services, biodiversity conservation, commodity production, and trade-offs at landscape scales. Frontiers in
Ecology and the Environment, 7: 4-11.
208 The Royal Society (2001) The role of land carbon sinks in mitigating global climate change. Policy document
10/01. The Royal Society, London.
209 Arora V.K. & Montenegro A. 2010. Small temperature benefits provided by realistic afforestation efforts.
Nature Geoscience, 4, 514-518; doi: 10.1038/ngeo1182
210
L.M. Russel et al. (2011). Ecosystem Impacts of Geoengineering: A Review for Developing a Science Plan.
Submitted to Ambio 20 June 2011.
211 IAASTD: http://www.agassessment.org/docs/SR_Exec_Sum_280508_English.htm
212 T.D. Searchinger et al (2009) Fixing a critical climate accounting error. Science, 326:
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shows that this assumption could be seriously flawed and that, in fact, biomass production
could incur a carbon debt of several decades or centuries.
1960
Habitat loss
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Production of biomass for carbon sequestration on a scale large enough to be climatically
significant would likely entail large changes in land use leading to the significant loss of
biodiversity habitats directly, or indirectly as biomass production displaces food crops, which,
in turn, leads to encroachment into natural areas. These effects are similar to those resulting
from expansion of biofuels.213,214,215. For example, a recent assessment of global “biochar”
potential (see section 5.2.4.2.2) indicates that sequestering 12% of annual anthropogenic
greenhouse gas emissions would require 556 million hectares of dedicated biomass
plantations, much of it through the conversion of tropical grasslands216. Besides the impacts
on biodiversity, these land use changes would entail net greenhouse gas emissions due to land
use change217,218. The production of biomass on previously degraded areas, if well-managed,
may be conducted in a way that delivers biodiversity benefits. However, even here, greater
benefits in terms of both biodiversity and net greenhouse gas reductions may be achieved
through restoration of natural habitats on these lands. 219,
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A 2009 study220 modelled the environmental consequences of an ambitious global cellulosic
biofuels program up to 2050. The study looked at two scenarios: one in which there were no
restrictions on deforestation and in which any land would be available for biofuel production
as long as it was economically viable ('deforestation scenario'), and the other in which the
conversion of natural forests and other 'unmanaged land' was limited to recent regional land
conversion rates ('intensification scenario'). The study concluded that the more optimistic
'intensification scenario' would see the loss of 3.4 million km2 of grasslands currently used for
grazing, 38% of the natural forest cover and 38% of wooded savannah in sub-Saharan Africa
based on 2000 figures. In Latin America, the same scenario would be associated with the loss
of 20% of natural forests and savannah in Latin America.
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Other impacts on biodiversity
www.princeton.edu/~tsearchi/writings/Fixing%20a%20Critical%20Climate%20Accounting%20ErrorEDITEDtim.pdf
213
Righelato, R and Spracklen, DV. (2007) Carbon Mitigation by Biofuels or by Saving and Restoring Forests?
Science 317 (902), 902.
214 Searchinger, T, Heimlich, R,. Houghton, R. A., Dong, F. Elobeid, A., Fabiosa, J., Tokgoz, T., Hayes, D., and
Yu, T. (2008) Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land Use
Change. Science. Published on-line 7 February 2008. Available from
http://www.sciencemag.org/cgi/content/abstract/1151861
215
Fargione, J., Hill, J., Tilman, D., Polasky, S. and Hawthorne, P. (2008). Land Clearing and the Biofuel Carbon
Debt. Science, 319(5867), 1235 - 1238. Available from http://www.sciencemag.org/cgi/ content/abstract/1152747.
216
D. Woolf et al (2010) Sustainable biochar to mitigate global climate change. Nature Communications 1, Article
56.
217 Searchinger, T, Heimlich, R,. Houghton, R. A., Dong, F. Elobeid, A., Fabiosa, J., Tokgoz, T., Hayes, D., and
Yu, T. (2008) Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land Use
Change. Science. Published on-line 7 February 2008. Available from
http://www.sciencemag.org/cgi/content/abstract/1151861.
218
Fargione, J., Hill, J., Tilman, D., Polasky, S. and Hawthorne, P. (2008). Land Clearing and the Biofuel Carbon
Debt. Science, 319(5867), 1235 - 1238. Available from http://www.sciencemag.org/cgi/ content/abstract/1152747.
219
Righelato, R and Spracklen, DV. (2007) Carbon Mitigation by Biofuels or by Saving and Restoring Forests?
Science 317 (902), 902.
220 J.M. Melillo et al (2009) Unintended Environmental Consequences of a Global Biofuels Program.
Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change, Report No.
168: www.calepa.ca.gov/cepc/2010/AsltonBird/AppAEx13.pdf
61
1985
1986
1987
1988
Proposals for carbon sequestration of carbon as crop residues in the ocean (see section
5.2.4.2.3) envisage the removal of some 30% of crop residues from agricultural systems221.
This is likely to have negative impacts on productivity, biodiversity, and in particular soil
quality.
1989
1990
1991
1992
1993
There are clear trade-offs between optimizing land for bioenergy crop yield and for
biodiversity benefits; where monocultures and invasive alien species are employed in the
production of biofuels the projected impacts on biodiversity are negative. If however, native
assemblages of species are planted on degraded land and managed in a sustainable manner,
benefits may be positive.
1994
Bioenergy Carbon Capture and Storage (BECCS)
1995
1996
1997
Bioenergy carbon capture and storage (BECCS) combines existing or planned technology for
bioenergy/biofuels and for carbon capture and storage (CCS). It involves harvesting biomass,
using it as a fuel, and sequestering the resulting CO2.222
1998
1999
Issues related to bioenergy production are covered above. Issues related to carbon capture and
storage are addressed in section 5.2.5
2000
5.2.4.2. Storage of carbon sequestered in biomass
2001
5.2.4.2.1. Charcoal production and storage (“Biochar”)
2002
2003
2004
“Biochar” involves the production of black carbon from biomass (charcoal), usually through
pyrolysis (decomposition in a low- or zero-oxygen environment), and its storage in soils or
elsewhere for up to thousands of years223.
2005
2006
Issues related to the production of biomass for charcoal production are covered under section
5.2.4.1, while issues related to the storage of charcoal in soils are addressed here.
2007
2008
2009
2010
2011
2012
2013
2014
Charcoal production and storage can help to slow the increase in atmospheric CO2
concentrations since it circumvents the natural process of biomass decomposition by microorganisms, which returns carbon to the atmosphere. Laboratory incubation and modeling
studies have shown biochar to be inherently stable and resistant to such decomposition224, due
to the bonds between its carbon atoms being much stronger than those in plant matter.
However, the assumption that black carbon is inherently stable is challenged by the results of
some field trials which have shown biochar impacts on soil carbon and soil carbon
sequestration to be unpredictable and not always positive even over a short time-span225,226.
2015
Impacts of charcoal storage in soils on biodiversity and ecosystems
2016
2017
2018
2019
There is a wide variety of raw materials (feedstocks) for creating charcoal – such as wood,
leaves, food waste and manure – and various conditions under which pyrolysis can take place.
These variations, combined with the diversity of soil types to which biochar can be added,
mean that the impacts of biochar on soils, crop yields, soil microbial communities and
221
Strand S.E. and Benford G. (2009) Ocean sequestration of crop residue carbon: Recycling fossil fuel carbon
back to deep sediments. Environmental Science and Technology 43, 1000-1007.
222 Gough, C. and P. Upham (2011). "Biomass energy with carbon capture and storage (BECCS or Bio-CCS)."
Greenhouse Gases: Science and Technology 1: 324-334 DOI: 10.1002/ghg.34
223 K. Spokas (2010) Review of the stability of biochar in soils: predictability of O:C molar ratios. Carbon
Management, 1(2): 289–330.
224 C. Cheng et al (2008) Stability of black carbon in soils across a climatic gradient. Journal of Geophysical
Research, 113, G02027.
225 Fate of soil-applied black carbon: downward migration, leaching and soil respiration, Julie Major at all, Global
Change Biology, Volume 16, Issue 4, April 2010; Long term effects of manure, charcoal and mineral fertilization
on crop production and fertility on a highly weathered Central Amazonian upland soil, Christoph Steiner et al,
2007, Plant Soil DOI 10.1007/s11104-007-9193-9
226 Nitrogen Retention and Plant Uptake on a highly weathered central Amazonian Ferralsol amended with
Compost and Charcoal, Christoph Steiner et al, J. Plant Nutr. Soil Sci. 2008, 171, 893–899
62
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detritivores are also highly variable227. In addition, the impacts of biochar on mycorrhizal
fungi are not yet fully understood228.
2022
2023
2024
2025
2026
As with increased soil carbon (discussed above), biochar could increase the amount of water
retained in the soil, thereby enhancing the resilience of ecosystems and potentially mitigating
the water-depleting effects of climate change in arid areas. However, while increasing the
amount of water retained in the soil as a result of biochar may have positive effects in some
areas, in other areas increased water retention could lead to more anoxic conditions.
2027
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Moreover, the deposition of biochar in a suitable terrestrial location is likely to require
considerable transport, burying and processing, which could compromise the growth, nutrient
cycling and viability of the ecosystems involved229.
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2033
There is a great deal of uncertainty surrounding the impacts of biochar on biodiversity and
ecosystem services due to a lack of published research on biochar. Compounding this
limitation is the fact that many field trials have relied on charcoal produced by wildfires rather
than by the modern method of pyrolysis proposed for biochar geo-engineering230.
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There is also considerable uncertainty surrounding the long-term effects of biochar on soil
productivity. Published field trials show that applying the same type of biochar at different
rates in the same region can have impacts on crop yields which vary from negative to neutral
to positive, even over a short time period231.
2038
5.2.4.2.2 Ocean biomass storage
2039
2040
2041
2042
2043
2044
2045
2046
2047
Ocean biomass storage (for example, proposals called CROPS – “Crop Residue Oceanic
Permanent Sequestration”), involves the deep ocean sequestration of terrestrial crop residues
on or in the seabed232, 233. These proposals suggest that up to 0.6 Gt C (30% of global annual
crop residues of 2 Gt C) could be available sustainably, deposited in an annual layer 4m deep
in an area of seabed of ~1,000 km2. However, a sustainable annual sequestration rate below 1
Gt C/yr makes it unlikely for CROPS alone to make a significant contribution to mitigating
climate change70.Potentially, charcoal (“biochar”) or other organic remains could also be
deposited on the seabed. It seems unlikely that deposition on the seabed would be the most
effective use of those residues (e.g. it would seem more useful to use them in BECCS).
2048
2049
Issues related to the production of biomass or crop residues are covered under section 5.2.4.1,
while issues related to the ocean storage of the biomass are addressed here.
2050
2051
2052
It should be noted that this technique may well be covered by the existing category of wastes
‘Organic material of natural origin’ in Annex I of the London Protocol and ‘Uncontaminated
organic material of natural origin’ in Annex I of the London Convention.234
227
J.E. Amonette et al (2009) Characteristics of biochar: microchemical properties In J. Lehmann and S. Joseph
(eds) Biochar for Environmental Management, Earthscan.
228 D.D. Warnock et al (2007) Mycorrhizal responses to biochar in soil: concepts and mechanisms. Plant Soil, 300:
9–20.
229 The Royal Society (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
230 S. Shackley and S. Sohi (eds). An Assessment of the Benefits and Issues Associated with the Application of
Biochar to Soil. UK Biochar Research Centre.
231 H. Asai et al (2009) Biochar amendment techniques for upland rice production in Northern Laos, 1. Soil
physical properties, leaf SPAD and grain yield. Field Crops Research, 111: 81-84.
232 Metzger R.A. and Benford G. (2001) Sequestering of atmospheric carbon through permanent disposal of crop
residue. Climatic Change 49: 11–19.
233 Strand S.E. and Benford G. (2009) Ocean sequestration of crop residue carbon: Recycling fossil fuel carbon
back to deep sediments. Environmental Science and Technology 43, 1000-1007.
76 International Maritime Organization (2010) Marine geoengineering: types of schemes proposed to date,
Scientific Group of the London Convention 33rd meeting, Scientific Group of the London Protocol 4th meeting.
Available online at http://www.imo.org/blast/blastDataHelper.asp?data_id=27646&filename=13.pdf )
63
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Impacts on biodiversity
2054
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2058
Where crop residues are deposited as ballasted bales, it is likely that there will be significant
physical impact, of a relatively local nature, on the seabed due to the sheer mass of the
material. In addition, there may be wider chemical and biological impacts through reductions
in oxygen and potential increases in H2S, CH4, N2O and nutrients arising from the degradation
of the organic matter.
2059
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The degradation of crop residue bales is likely to be slow due to the ambient conditions of
low temperature and limited oxygen availability; the apparent lack of a marine mechanism for
the breakdown of ligno-cellulose material; and the anaerobic conditions within the bales235.
While, it can be argued that potential impacts could be reduced if deposition occurred in areas
of naturally high sedimentation, such as off the mouths of major rivers (e.g. Mississippi)236,
many such areas are already susceptible to eutrophication and anoxia from existing
anthropogenic, land-derived nutrient inputs. These effects are likely to be worsened if
increased use of inorganic fertilizer is needed to replace the nutrients removed in the crop
residues.
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The type of packaging would also be significant when assessing potential impacts as its
permeability to water and gases has the potential to influence the flux of substances into the
near seabed waters. If the bales are buried within the sediment, then impacts on near seabed
waters are likely to be significantly reduced; additional manipulations would, however,
almost certainly have cost implications.
2073
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The addition of significant amounts of organic matter to the deep sea floor could lead to
greater densities and biomasses of benthic organisms over a long period in the locations
where the crop residues are deposited, a perturbation from the natural state.
2076
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2084
The limited knowledge of ecosystem services from the deep sea combined with limited
understanding of the impacts of ocean biomass storage lead to a lack of understanding about
its impacts on ecosystem services. However, if done in the shallower end of the water depths
suggested (1000 – 1500 m), its impacts on ecosystem services could be more significant since
this is just within the range of deep sea fisheries. Whilst the area directly affected could be
relatively restricted (on a global scale), larger-scale and longer-term indirect effects of oxygen
depletion and deep-water acidification could be regionally significant if there is cumulative
deposition of many gigatonnes of organic carbon to the seafloor, and most of this is
eventually decomposed.
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There are large unknowns due to limited knowledge as indicated above. No field experiments
have been carried out and only a few peer-reviewed papers on the proposed technique have
been published. Furthermore, while there is a lot of knowledge about the impact of organic
enrichment on continental shelf environments, it is unclear whether this is easily translated
into the very different deep sea environment.
2090
5.2.5 Carbon Dioxide Capture and Storage
2091
5.2.5.1 Carbon Dioxide Capture from Ambient Air
2092
2093
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2097
Air capture is an industrial process that captures CO2 from exhaust streams or the ambient air
and produces a pure CO2 stream for use or disposal. Three main technologies are being
explored for doing so: adsorption of CO2 onto solids, absorption into highly alkaline
solutions, and absorption into moderately alkaline solutions with a catalyst. The main problem
is the high energetic cost. The technical feasibility of air capture technologies is in little doubt
and as already been demonstrated (e.g. in the commercial removal of CO2 from air for use in
235
Strand S.E. and Benford G. (2009) Ocean sequestration of crop residue carbon: Recycling fossil fuel carbon
back to deep sediments. Environmental Science and Technology 43, 1000-1007.
236 Strand S.E. and Benford G. (2009) Ocean sequestration of crop residue carbon: Recycling fossil fuel carbon
back to deep sediments. Environmental Science and Technology 43, 1000-1007.
64
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subsequent industrial processes). However, no large-scale geo-engineering prototypes have
yet been tested. Given the high net CO2 emissions that would results from air capture that was
powered by fossil fuels, it would appear that the system would only be viable if a
geographically isolated non-carbon power source was available.
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Capturing CO2 from the ambient air (where its concentration is 0.04%) is much more difficult
and energy intensive than capturing CO2 from exhaust streams of power stations where the
CO2 is about 300 times of magnitude higher. A recent study suggests that the energetic and
financial costs of capturing CO2 from the air are likely to have been underestimated
previously, therefore placing the viability of this approach in doubt. Such approaches are
discussed extensively in Chapter 6 of the IPCC Special Report on Carbon Dioxide Capture
and Storage237.
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This section focuses only on the step of capturing CO2 from the air. Storage of the CO2 socaptured is considered in section 5.2.6.
2111
Small land-use requirements
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Negative impacts on biodiversity through habitat loss due to land-use conversion could be
relatively small for this family of technologies, since air capture systems have a land-use
footprint that is hundreds or thousands of times smaller per unit of carbon removed than that
of biomass-based approaches.238
2116
Fresh-water use
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Some proposed methods of air capture have a high requirement for fresh water, which is
already a scarce resource. Furthermore, the disposal of captured CO2, and the potential for
leakage, might also impact terrestrial and marine ecosystems (as discussed in section 5.2.4.2).
2120
5.2.5.2. CO2 storage techniques
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CO2 that has already been extracted from the atmosphere by other geo-engineering techniques
(e.g. air capture) must be stored either in the ocean or in sub-surface geological reservoirs.
Such approaches are discussed comprehensively in Chapter 6 of the IPCC Special Report on
Carbon Capture and Storage239.
2125
5.2.5.2.1 Ocean CO2 storage
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The main variants of ocean CO2 storage involve either adding CO2 to middle/deep ocean
waters or putting CO2 in depressions in the seabed to form lakes/pools240, 241. It has also been
suggested to deposit solid CO2 blocks in the sea242; inject liquid CO2 a few hundred metres
into deep-sea sediments at greater than 3,000 m depth243, displace the methane by CO2 in
methane hydrates on continental margins and in permafrost regions244; or discharge liquid
CO2 mixed with pulverized limestone at an intermediate depth of greater than 500 m in the
ocean245. However, the economic viability of these methods has not been assessed, and none
237
IPCC IPCC (2005b) IPCC Special Report on Carbon Capture and Storage, Cambridge University Press, 431
pp.
238 The Royal Society (2009) Geoengineering the Climate: Science, Governance and Uncertainty. RS Policy
document 10/09. The Royal Society, London, 82 pp
239 IPCC IPCC (2005b) IPCC Special Report on Carbon Capture and Storage, Cambridge University Press, 431
pp.
240 Nordhaus, W.D. (1975) Can we control carbon dioxide? IIASA-Working Paper WP-75-63, June 1975.
241 Marchetti C (1977) On geoengineering and the CO problem. Climatic Change 1:59–68
2
242 Murray CN, Visintini L, Bidoglio G and Henry B (1996) Permanent storage of carbon dioxide in the marine
environment: The solid CO2 penetrator. Energy Conversion and Management 37 (6-8) 1067-1072.
243 House K Z, Schrag D P, Harvey CF and Lackner KS (2006) Permanent carbon dioxide storage in deep-sea
sediments. PNAS 103 (33) 12291-12295.
244 Park Y, Kim D-Y, Lee J-W, Huh D-G, Park K-P, Lee J and Lee H (2006) sequestering carbon dioxide into
complex structures of naturally occurring gas hydrates. PNAS 103, 12690-12694.
65
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would permanently sequester the CO2 since it will eventually return to the atmosphere over
century-to-millennial time scales depending on where it was introduced. So whilst they could
help in buying time, it would be at the expense of future generations.
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Disposal of CO2 into the water column, on or in the seabed (other than in sub-seabed
geological formations), is not permitted under the global instruments of the London Protocol
1996 and is explicitly ruled out under the regional OSPAR Convention covering the north
East Atlantic region. The situation under the London Convention 1972 is currently unclear.
2140
Impacts on biodiversity and ecosystem services
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Ocean CO2 storage will necessarily alter the local chemical environment, with a high
likelihood of biological effects. Knowledge available for surface oceans indicates that effects
on mid-water and deep benthic fauna/ecosystems is likely on exposure to pH changes of 0.1
to 0.3 units, primarily in marine invertebrates and possibly in unicellular organisms246.
Calcifying organisms are the most sensitive to pH changes; they are however naturally less
abundant in deep water, particularly if calcium carbonate saturation is already <1.0 (i.e.
CaCO3 dissolves, unless protected).
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Total destruction of deep seabed biota that cannot flee can be expected if lakes of liquid CO 2
are created. The scale of such impacts would depend on the seabed topography, with deeper
lakes of CO2 affecting less seafloor area for a given amount of CO2. However, pH reductions
would still occur in large volumes of water near to such lakes247, and mobile scavengers are
likely to be attracted (and themselves deleteriously affected) by the scent of recently-killed
organisms248.
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Ecosystem services from the deep seabed are generally of an indirect nature, relating to
nutrient cycling and long term climate control. However, all deep water does eventually
return to the surface and/or mix with the rest of the ocean. The use of the deep sea for largescale CO2 storage will therefore eventually reduce ocean pH as a whole, with potential effects
greatest in upwelling regions (currently highly productive and supporting major fisheries).
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The chronic effects of direct CO2 injection into the ocean on ecosystems over large ocean
areas and long time scales have not yet been studied, and the capacity of ecosystems to
compensate or adjust to such CO2 induced shifts is unknown. Several short-term and very
small field experiments (litres) have, however, been carried out, e.g. on meiofauna249, and
peer-reviewed literature on potential CO2 leakages from geological sub-sea storage250 is also
relevant.
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It is expected that, where CO2 storage in sub-seabed geological formations is authorized
pursuant to a permit under the London Protocol, that information on the leakage and potential
impacts will be reported and amassed over time. It should also be noted that the injection into
the water column of CO2 would generally be considered to be disposal at sea from a ship,
platform or other structure at sea and would not be allowed under the London Protocol.
2170
5.2.5.2.2. CO2 storage in sub-surface geological reservoirs
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CO2 storage in sub-surface geological reservoirs is already being implemented at pilot-scale
levels, and has been used industrially as part of enhanced oil recovery. Based in part on this
245
Golomb D and Angelopolous A (2001) A benign form of CO2 sequestration in the ocean. Proceedings of the 5th
International Greenhouse Gas Technology Congress, CSIRO Publ, 463-468.
246 Gattuso J.-P. & Hansson L. 2011. Ocean Acidification. Oxford University Press
247 IPCC (2005b) IPCC Special Report on Carbon Capture and Storage, Cambridge University Press, 431 pp.
248 Tamburri M.N., Peltzer E.T., Friederich G.E., Aya I., Yamane K. & Brewer P. 2000. A field study of the effects
of CO2 ocean disposal on mobile deep-sea animals. Marine Chemistry 72, 95-101.
249 Barry J.P., Buck K.R., Lovera C.F., Kuhnz L., Whaling P.J., Peltzer E.T., Walz P. & Brewer P.G. 2004. Effects
fo direct ocean CO2 injection on deep-sea meiofauna. J Oceanography, 60, 759-766
250 IPCC (2005b) IPCC Special Report on Carbon Capture and Storage, Cambridge University Press, 431 pp.
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experience, the risks are generally regarded as low. However, leakage from such reservoirs
could have locally significant biodiversity implications.251
2175
5.6. Sequestration of other Greenhouse Gasses
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This report focuses on the removal of carbon dioxide from the atmosphere but there are some
indications that other greenhouse gasses could also be removed although there is currently no
supportive peer reviewed literature available on such proposals.
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251
Wilson E.J., Johnson T.L. and Keith D.W. 2003. Regulating the ultimate sink: managing the risk of geological
CO2 storage. Environ Sci Technol 37, 3476-3483.
Oruganti, Y. and Bryant, S. (2009) Pressure build-up during CO2 storage in partially confined aquifers. Energy
Procedia, 1(1): 3315-3322.
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CHAPTER 6. SOCIAL, ECONOMIC, CULTURAL AND ETHICAL
CONSIDERATIONS OF CLIMATE-RELATED GEO-ENGINEERING
2183
6.1 Introduction
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Climate change is likely to have serious impacts on biodiversity, ecosystems and associated
ecosystem services. The social, economic and cultural implications of un-controlled climate
change and continued degradation of ecosystems should not be underestimated (see chapter
3).
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Similar to the discussion on the impacts of climate change on biodiversity, the social,
economic and cultural considerations regarding geo-engineering have significant inter- and
intra-generational equity issues.
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Geo-engineering proposals are likely to meet not only support, but also opposition, especially
considering the present divergence of opinions about potential risks and benefits. All new
technologies or techniques are embedded in a wider social context and have social, economic
and cultural impacts that might become apparent only once they have been employed.
However, due to its intentionality and its potential impacts, geo-engineering raises issues
beyond technical scientific assessments. Nuclear power, genetically modified organisms
(GMOs) and nano-technologies have shown the importance to connect scientific research to a
wider social context.
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The Conference of the Parties, through its decision X/33 requested the Executive Secretary to
identify social, economic and cultural considerations associated with the possible impacts of
geo-engineering on biodiversity.
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In this chapter, we discuss a number of social, economic and cultural aspects of geoengineering, and the role of indigenous groups and local communities in the context of geoengineering and biodiversity. The first parts deal with social, economic and cultural issues
that are relevant for geo-engineering in general.252 The ambition here is to put geoengineering technologies in a wider social context, and to highlight social, political, economic
and cultural issues that ought to be of interest for the Parties of the CBD, and the readers of
this report. The second part of the chapter has an explicit focus on potential social concerns
associated with different geo-engineering proposals and technologies and their impacts on
biodiversity.
2211
6.2. Available information
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
Assessing the social, economic and cultural impacts of geo-engineering technologies as they
relate to biodiversity is an important, yet difficult task considering the current state of
knowledge and the lack of peer-reviewed literature on the topic. It should be noted that there
is a lack of published academic studies that specifically address the issue. It has also been
questioned whether peer-reviewed literature can adequately reflect indigenous knowledge;
knowledge which is often as much a process of knowing as it is a thing that is known, and so
does not lend itself to the practice of documentation253. This is particularly worrisome
considering the role these communities play in actively managing ecosystems, sometimes
through an active application of local ecological knowledge that has evolved during
considerable time frames through co-management processes and social learning254.
252
We acknowledge that this first part extends beyond the explicit mandate of the group, but has been included to
put the technologies in a wider social context, as well as to respond to comments on earlier drafts of this report.
253
A. Agrawal, 1995, Indigenous and scientific knowledge: some critical comments, Indigenous Knowledge and
Development Monitor, 3 (3): 3-6. F. Berkes, 2008, Sacred Ecology, 2nd edition, Routledge, New York, USA.
254 Berkes, F., J Colding and C Folke (2004). Navigating Social-Ecological Systems – Building Resilience for
Complexity and Change. Cambridge University Press, Cambridge. 397 pp.
68
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2223
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2230
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Some work on this matter has been conducted within the framework of CBD activities on
biodiversity and climate change, including through the workshop on opportunities and
challenges of responses to climate change for Indigenous and local Communities, their
traditional knowledge and biological diversity held the 25 - 28 March 2008 in Helsinki,
Finland255, as well as through the consideration of the role of traditional knowledge
innovations and practices during the second Ad hoc Technical Expert Group on Biodiversity
and Climate Change256, however further work remains to be done. In addition, there is a
growing literature on social dimensions of geo-engineering257, including examples of social
perceptions from historic efforts to engineer the climate and other large-scale planetary
processes258. Issues related to geo-engineering ethics, governance and socio-political
dimensions have also been discussed within the geo-engineering research community, as
exemplified by the Oxford Principles259 and the subsequent Asilomar principles.
2234
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2237
It should also be noted that there is very little information available about the perspectives
from indigenous peoples and local communities, especially among developing countries
within geo-engineering discussions.260 The CBD Secretariat has initiated a process to bring in
the views of indigenous communities, and the results will be presented in a separate report.261
2238
6.3 General social, economic and cultural considerations
2239
2240
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There are a number of social, economic and cultural considerations from geo-engineering
technologies that may emerge, regardless of the specific geo-engineering approach
considered. These considerations are not necessarily unique for geo-engineering, but have
clear parallels to on-going discussions on social dimensions of climate change, emerging
technologies, and complex global risks. It should be restated that this is not intended to be a
complete all-encompassing analysis of costs and benefits, but should rather be seen as social,
economical and cultural issues of potential concern. In addition, social perceptions of risks in
general, are highly differentiated across social groups, and highly dynamic 262, and pose
255
Opportunities and challenges of responses to climate change for Indigenous and Local Communities, their
Traditional Knowledge and Biological Diversity. 25 - 28 March 2008 - Helsinki, Finland. Meeting report:
http://www.cbd.int/doc/meetings/cop/cop-09/information/cop-09-inf-43-en.pdf; Meeting documents:
http://www.cbd.int/doc/?meeting=EMCCILC-01
256 Secretariat of the Convention on Biological Diversity (2009) Connecting Biodiversity and Climate Change
Mitigation and Adaptation: Report of the Second Ad Hoc Technical Expert Group on Biodiversity and Climate
Change. Technical Series No.41. CBD, Montreal, 126 pp
257 Stanford Journal of Law and Science, special issue 2009: Barrett, Schelling, Victor, Gardner REFS
258 Fleming, James Rodger. 2006. “The Pathological History of Weather and Climate Modification: Three cycles
of promise and hype,” Historical Studies in the Physical Sciences 37, no. 1 (2006): 3-25.
http://www.colby.edu/sts/06_fleming_pathological.pdf Fleming, James Rodger. 2011. “Iowa Enters the Space
Age: James Van Allen, Earth’s Radiation Belts, and Experiments to Disrupt Them,” Annals of Iowa 70 (Fall
2011), in press.
259 Rayner, S., Redgwell C., Savulescu, J., Pidgeon, N. and Kruger, T. (2009) Memorandum on draft principles for
the conduct of geoengineering research. House of Commons Science and Technology Committee enquiry into The
Regulation of Geoengineering. The call by the American Geophysical Union Policy Statement on Geo-engineering
the Climate System for “coordinated study of historical, ethical, legal, and social implications of geo-engineering
that integrates international, interdisciplinary, and intergenerational issues and perspectives and includes lessons
from past efforts to modify weather and climate”, is nevertheless still relevant in this context. AGU Position
Statement. Geoengineering the Climate System. Statement adopted by Council 13 December 2009. Adopted from
the statement written by the American Meteorological Society and adopted by the AMS Council on 20 July 2009:
http://www.agu.org/sci_pol/positions/geoengineering.shtml.
260 However, public engagement initiatives have now been piloted in the developed world, as a means of gauging
public opinions on geo-engineering, see Ipsos MORI, 2010, Experiment Earth? Report on a Public Dialogue on
Geoengineering. Available online at http://www.nerc.ac.uk/about/consult/geoengineering-dialogue-final-report.pdf
261 UNEP/CBD/SBSTTA/16/INF/30: Impacts of climate related geo-engineering on biodiversity: views and
experiences of indigenous and local communities and stakeholders.
262 Kasperson, R. E., Renn, O., Slovic, P., Brown, H. S., Emel, J., Goble, R., Kasperson, J. X., et al. (1988). The
Social Amplification of Risk: A Conceptual Framework. Risk Analysis, 8(2), 177-187. doi:10.1111/j.15396924.1988.tb01168.x
69
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particular socio-political challenges in settings defined by complex bio-geophysical
interactions.263 This complicates any projection of how the general public, non-governmental
organizations and governments would perceive any experimentation and deployment of geoengineering technologies.
2251
6.3.1 Ethical considerations
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Humanity is now the major changing force on the planet, a new geological era proposed as
the “Anthropocene”.264 This shift has important repercussions, not only because it forces us to
consider multiple and interacting global environmental changes,265 but also because it opens
up difficult discussions on whether it is desirable to move from unintentional modifications of
the Earth system, to an approach where we intentionally try to modify the climate and
associated bio-geophysical systems to avoid the worst outcomes of climate change. Hence,
the very fact that the international community is presented with geo-engineering as a potential
option to be further explored is a major social and cultural issue.
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Geo-engineering poses numerous ethical challenges. It also requires the international
community to resolve the conflicting objectives of avoiding the effects of global climate
change vis-à-vis avoiding the risks of geo-engineering.
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Although some upstream public engagement on geo-engineering has been trialled266,267
current discussions on geo-engineering are often based on technical approaches whose
implications are not readily understood nor easily assessed268. There is a growing discussion
and literature on ethical considerations related to geo-engineering, including issues of “moral
hazard” 269; intergenerational issues of submitting future generations to the need to maintain
the operation of the technology or suffer accelerated change270; the possibility that
development and uses of geo-engineering techniques are perceived to be threatening by
governments 271; as well as the question of whether it is ethically permissible to remediate one
pollutant by introducing another272.
263 Galaz, V., Moberg, F., Olsson, E.-K., Paglia, E., & Parker, C. (2011). Institutional and Political Leadership
Dimensions of Cascading Ecological Crises. Public Administration, 89(2), 361-380. doi:10.1111/j.14679299.2010.01883.x
264 Crutzen et al 2011
265 Rockström et al 2009, ”A Safe Operating Space for Humanity”, Nature; Steffen, W., Persson, Ã…., Deutsch,
L., Zalasiewicz, J., Williams, M., Richardson, K., Crumley, C., et al. (2011). The Anthropocene: From Global
Change to Planetary Stewardship. Ambio. doi:10.1007/s13280-011-0185-x
266
Ipsos MORI, 2010, Experiment Earth? Report on a Public Dialogue on Geoengineering. Available online at
http://www.nerc.ac.uk/about/consult/geoengineering-dialogue-final-report.pdf
267 Karen Parkhill and Nick Pidgeon, 2011, Public Engagement on Geoengineering Research: Preliminary Report
on the SPICE Deliberative Workshops [Technical Report], Understanding Risk Group Working Paper, 11-01,
Cardiff University School of Psychology. Available online at
http://psych.cf.ac.uk/understandingrisk/docs/spice.pdf
268 Ipsos MORI, 2010, Experiment Earth? Report on a Public Dialogue on Geoengineering. Available online at
http://www.nerc.ac.uk/about/consult/geoengineering-dialogue-final-report.pdf
269 Alan Robock, 2008, 20 Reasons Why Geoengineering May Be A Bad Idea, Bulletin of the Atomic Sciences, 64
(2): 14-18. Available online at http://www.thebulletin.org/files/064002006_0.pdf
270 Gardiner, Stephen M. (2011). “Some Early Ethics of Geoengineering the Climate: A Commentary on the
Values of the Royal Society Report”, Environmental Values, Volume 20, Number 2, May 2011 , pp. 163-188.
271 Fleming, James (2010). Fixing the Sky
272 Hale, B. and L. Dilling (2011). “Geoengineering, Ocean fertilization, and the Problem of Permissible
Pollution”, Science, Technology and Human Values, 36(2): 190-212.
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6.3.2 Unintended consequences and technological lock-in
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Technological innovation has in very many ways helped to transform societies and improve
the quality of life, but not always in a sustainable way. 273 Failures to respond to early
warnings of unintended consequences of particular technologies have been documented274.
The possibilities of unintended side effects in the large-scale application of geo-engineering
techniques is an often-raised concern in the literature and general debate especially for Solar
Radiation Management (see chapter 4). The concept of ‘technologies of hubris’ has been
introduced, calling for an increased balance between the concept that technology can solve
problems and the concern over whether technological approaches are the best option when
considering social and ethical considerations275.
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An additional issue that has been raised is the possibility of technological, political and social
“lock in” - that is the possibility that the development of geo-engineering technologies also
result in the emergence of vested interests and increasing social momentum. It has been
argued that this path dependency could make deployment more likely, and/or limit the
reversibility of geo-engineering techniques.276
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6.3.3 Governance and legal considerations
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Issues related to geo-engineering governance and regulation have gained increased
prominence in the literature.277 It should be noted that the challenges for regulation and
governance of geo-engineering include the variety of evolving technologies as well as their
different stages of development – ranging from theory to modelling, to sub-scale field testing,
and large scale deployment278. Governance structures also need to provide different functions
ranging from ensuring transparency, participation, containing risks, the coordination of
science, bridging the science-policy divide, and create structures to secure funding279.
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These issues, along with precautionary principle/approach and human rights approaches, are
discussed in detail in a parallel legal study assumed in line with CBD Decision X/33 entitled
“Regulatory Framework of Climate-related Geo-engineering Relevant to the Convention on
Biological Diversity”, and are therefore not explored in detail here.
273 Westley, F., Olsson, P., Folke, C., Homer-Dixon, T., Vredenburg, H., Loorbach, D., Thompson, J., et al.
(2011). Tipping Toward Sustainability: Emerging Pathways of Transformation. Ambio. doi:10.1007/s13280011-0186-9
274 Harremoës, P., & Agency, E. E. (2001). Late lessons from early warnings: the precautionary principle 18962000 (pp. 1-211). Office for Official Publications of the European Communities.
275 Sheila Jasanoff. Technologies of Humility: Citizen participation in governing Science. Minerva, 2003.
http://sciencepolicy.colorado.edu/students/envs_5100/jasanoff2003.pdf
276 Royal Society (2009, pp.39, 45). See also literature on socio-technical regimes e.g. Arthurs, BA (1989).
”Competing technologies, Increasing returns and lock-in by historical events”, The Economic Journal, 99: 116131.
Geels, F. (2004). From sectoral systems of innovation to socio-technical systems- Insights about dynamics and
change from sociology and institutional theory. Research Policy, 33(6-7), 897-920.
doi:10.1016/j.respol.2004.01.015
277 Royal Society (2009), Macnaghten, P., & Owen, R. (2011). Good governance for geoengineering. Nature,
479, 2011; Reynolds, J. (2011). The Regulation of Climate Engineering. Environmental and Resource
Economics, 3, 113-136.GAO
278 Blackstrock, J., N. Mooore and C. Kehler Siebert (2011). Engineering the Climate – Research questions and
policy implications. UNESCO-SCOPE-UNEP Policy Briefs. November 2011.
279 Bodansky 2011
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6.3.4 Societal distribution considerations
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Geo-engineering could raise a number of questions regarding the distribution of resources and
impacts within and amongst societies and across time. First, access to natural resources is
needed for some geo-engineering. Competition for limited resources can be expected to
increase if geo-engineering technologies emerge as a competing activity for land or water use.
For example, possible competition for land as a result of land based albedo changes, or land
based CDR will reduce land available for other uses such as the production of food crops,
medicinal plants or the exploitation of non-timber forest products. These competing demands
for land use can increase social tensions unless addressed by national and local institutions280.
In addition, changes in land use may impact indigenous people’s cultural and spiritual values
of natural areas, sacred groves and water shades281.
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These issues could also be relevant in the marine environment where experimentation or
deployment of geo-engineering proposals such as ocean fertilization could impact traditional
marine resource use282,283,284,285 The use of the deep water as reservoirs for storage of CO2 or
biomass, as well as for ocean fertilization, would also use ocean space. To the extent that
most of these activities would happen on the high seas, there are unlikely to raise significant
distributional issues as a social consideration.
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Enhanced weathering on land however will have clear local impacts as it requires large
mining areas and associated transport infrastructure. In addition, the mineral resources
required will only be available in certain locations, therefore reducing the opportunity for
choosing between alternative sites. Based on historical experience, large mining activities
could have serious social implications. In addition, land space is needed for weathering to
happen.
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Second, the distribution of impacts of geo-engineering are not likely to be even or uniform as
are the impacts of climate change itself. Regarding impacts on climate, this appears to be
mainly an issue arising from SRM. Regarding other impacts, CDR could have local and
possibly also regional impacts that could raise distributional issues. Such impacts are explored
below in this chapter. Where distributional effects arise, this raises questions about how the
uneven impacts can be addressed for instance through proper governance mechanisms.
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Third, as with climate change, geo-engineering could also entail intergenerational issues. As a
result of possible technological “lock in”, future generations might be faced with the need to
maintain geo-engineering measures in general in order to avoid impacts of climate change.
This mainly has been identified as an issue for SRM. However, it is also conceivable that
CDR-techniques entail similar “lock in” effects depending on emission trajectories.
Conversely, it could be argued that not pursuing further research on geo-engineering could
limit future generations’ options for reducing climate risk.
280
Trumper, K. et al. (2009). The Natural Fix? The role of ecosystems in climate mitigation. UNEP rapid response
assessment. UNEP, Cambridge, UK
281 UNFF “Cultural and Social Values of Forests and Social Development”. UN Economic and Social Council.
E/CN.18/2011/5. New York, 2011.
282 Glibert, P M. (2008). Ocean urea fertilization for carbon credits poses high ecological risks. Marine pollution
bulletin, 56(6), 1049-1056.
283 IMO 2007. Convention on the Prevntion of Marine Pollution by dumping of wastes and other matter, 1972 and
its 1996 Protocol. Statement of concern regarding iron fertilization of the oceans to sequester CO2.
http://www.whoi.edu/cms/files/London_Convention_statement_24743_29324.
284 Sedlacek, L., Thistle, D., Carman, K.R., Fleeger, J.W and Barry, J.P. 2009. Effects of carbon dioxide on deepsea harpacticoids. ICES International Symposium – Issues confronting the deep oceans, 27 – 30 April, 2009,
Azores, Portugal.
285 OSPAR, 2007. OSPAR Decision 2007/1 to prohibit the storage of carbon dioxide streams in the water column
or on the sea-bed. Available at www.ospar.org/v-measure /get_page.asp?
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6.3.5. Political considerations
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There are also a number of social and political considerations to bear in mind especially when
considering SRM. In an international context, countries and societies will have to dealing
with the possibility of unilateral pursuit or deployment of geo-engineering. In cases in which
geo-engineering experimentation or interventions have (or are suspected to have)
transboundary affects or impacts on areas beyond national jurisdiction, geopolitical tensions
could arise regardless of causation of actual negative impacts, especially in the absence of
international agreement.286.
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Furthermore, some civil society organizations have expressed opposition to geo-engineering
experiments and deployment287,288,289. Tensions could also increase in cases where geoengineering technologies are combined with biotechnology (such as albedo enhanced crops)
and nanotechnology (under consideration for aerosols) and where actors are perceived to have
ulterior motives. Polarization of the debate could prove detrimental to political decisionmaking.290
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6.4. Specific social, economical and cultural considerations of geo-engineering
technologies as they relate to biodiversity
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Climate change is expected to result in altered ecosystems consisting of new assemblages of
species291, and therefore affect biodiversity in ways that are relevant for all sort of local uses
of land-based and marine ecosystems, and their associated ecosystem services. Reducing the
impacts of climate change through geo-engineering interventions may in theory address the
loss of ecosystems upon which traditional knowledge is based. On the other hand, deployment
of geo-engineering interventions may itself alter ecosystems (see examples below), resulting
in this impact being offset or eclipsed292. This however, is highly dependent on the geoengineering technology of interest, how they are deployed, and the institutions (local and
national) in place.
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In addition to the social considerations that generally arise from geo-engineering, in this
section we briefly elaborate social, economical and cultural considerations that result
specifically from geo-engineering’s impacts on biodiversity.
286
The Royal Society (2009). Geoengineering the climate. Science, governance and uncertainty. London, 82
pages, Scott Barrett (2008). “The Incredible Economics of Geoengineering”, Environ Resource Econ (2008)
39:45–54; Jason J Blackstock and Jane CS Long (2009). “The Politics of Geoengineering”, Science, Vol. 327 no.
5965 p. 527;
287 ETC Group, 2011, Open Letter to IPCC on Geoengineering. Available online at
http://www.etcgroup.org/upload/publication/pdf_file/IPCC_Letter_with_Signatories_-_7-29-2011.pdf
288 Karen Parkhill and Nick Pidgeon, 2011, Public Engagement on Geoengineering Research: Preliminary Report
on the SPICE Deliberative Workshops [Technical Report], Understanding Risk Group Working Paper, 11-01,
Cardiff University School of Psychology. Available online at
http://psych.cf.ac.uk/understandingrisk/docs/spice.pdf
289 Poumadère, M., R. Bertoldo, J.Samadi (2011) "Public perceptions and governance of controversial
technologies to tackle climate change: nuclear power, carbon capture and storage, wind, and geoengineering",
Climate Change. Advance Review DOI: 10.1002/wcc.134.
290 Bodle, Ralph, "International governance of geoengineering: Rationale, functions and forum", in: William C.G.
Burns (ed.), Geoengineering and climate change, Cambridge University Press (submitted February 2011;
forthcoming 2012)
291
John Williams and Stephen Jackson, 2007, Novel Climates, No-Analog Communities, and Ecological
Surprises, Frontiers in Ecology and the Environment, 5 (9): 475-482. Available online at
http://www.frontiersinecology.org/paleoecology/williams.pdf
292 H.D. Matthews and S.E. Turner (2009) Of mongooses and mitigation: ecological analogues to geoengineering.
Environmental Research Letters, 4 (4), 045105.
73
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6.4.1 Geo-engineering, and indigenous and local communities and stakeholders
Decision X/33 calls for the integration of the views and experiences of indigenous and local
communities and stakeholders into the consideration of the possible impacts of geoengineering on biodiversity and related social, economic and cultural considerations.
Integrating such views is important as indigenous peoples and local communities, especially
in developing countries, tend to be among the populations whose livelihoods are most reliant
upon biodiversity resources. In addition, disadvantaged users of ecosystems and their
associated ecosystem services, are at constant risk of losing out in conflicts related to local
resources, have less of a voice in decision-making at all levels, and may have less knowledge
of regulations and policies to support their interests293,294.
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On the other hand, there is considerable uncertainty concerning the impacts of any
environmental change on indigenous peoples and local communities since most such impacts
are difficult to predict with current modelling capabilities298. Furthermore, there is the risk
that geo-engineering, in some instances, could effect change far more rapidly even than
climate change itself299.
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In order to ensure that the impacts of geo-engineering on indigenous peoples and local
communities are adequately considered and addressed, there is a role for such stakeholders in
various phases of geo-engineering research, ranging from theory and modelling, technology
development, subscale field-testing; and potential deployment. The participation of
indigenous peoples and local communities could hence be included in all parts of research
development, especially in cases where technological interventions are projected to have
impacts for biodiversity and ecosystem services.
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Guidelines for the consideration of the views and knowledge of indigenous peoples and local
communities have already been proposed by the Second Ad hoc Technical Expert Group on
The issue here is as much about physical resources, as about cultural uses and worldviews
associated with ecosystems and their management such as forest taboo systems in
Madagascar295, and the unique cultural features of Balinese water temples296.
All forms of environmental change – resulting from geo-engineering or not – have local
implications for livelihoods and ecosystem services. In fact, the Second Ad hoc Technical
Expert Group on Biodiversity and Climate Change concluded that indigenous people will be
disproportionately impacted by climate change because their livelihoods and cultural ways of
life are being undermined by changes to local ecosystems 297. As such, if geo-engineering can
reduce the negative impacts of climate change, without effecting more environmental change
than that which is avoided, geo-engineering could contribute to the preservation of traditional
knowledge, innovations and practices.
293
Trumper et al. 2009:49-50
Bridging Scales and Epistemologies: Linking Local Knowledge and Global Science in Multi-Scale
Assessments Conference; Alexandria, Egypt · March 17-20, 2004, under the title: “Learning from the Local:
Integrating Knowledge in the Millennium Ecosystem Assessment". Available at:
http://www.millenniumassessment.org/documents/document.349.aspx.pdf
295 Tengö, M., K. Johansson, F. Rakotondrasoa, J. Lundberg, J-A Andriamaherilala, J-A Rakotoarisoa and T.
Elmqvist (2007). Taboos and Forest Governance: Informal Protection of Hot Spot Dry Forest in Southern
Madagascar. Ambio, Vol. 36, Issue 8, pg(s) 683-691.
296 Lansing, S. (2006). Perfect Order – Recognizing Complexity in Bali. Princeton University Press, Princeton.
297 Secretariat of the Convention on Biological Diversity. (2009) (a). Connecting Biodiversity and Climate Change
Mitigation and Adaptation: Report of the Second Ad Hoc Technical Expert Group on Biodiversity and Climate
Change. Montreal, Technical Series No. 41, 126 pages.
298 Robock, A. Bunzl, M. Kravitz, B. Georgiy L. Stenchikov, A Test for Geoengineering? Science 29 January
2010: Vol. 327. no. 5965, pp. 530 - 531
299 The Royal Society, 2009, Geoengineering The Climate: Science, Governance and Uncertainty, The Royal
Society, London, UK.
294
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Biodiversity and Climate Change with regards to climate change300. These guidelines (see box
1) may be useful to consider by scientists and national governments alike when assessing the
social, economic and cultural impacts of geo-engineering.
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As noted above, the CBD Secretariat has initiated a separate process to bring in the views of
indigenous communities, and the results will be presented in a different report.301
Box 1: Activities to promote the consideration of the views of indigenous peoples and local
communities:

Promote the documentation and validation of traditional knowledge, innovations and
practices. Most knowledge is not documented and has not been comprehensively
studied and assessed. Therefore there is need to enhance links between traditional
knowledge and scientific practices.

Revitalize traditional knowledge, innovations and practices on climate change
impacts on traditional biodiversity based resources and ecosystem services through
education and awareness-raising, including in nomadic schools.

Explore uses of and opportunities for community-based monitoring linked to
decision-making, recognizing that indigenous people and local communities are able
to provide data and monitoring on a whole system rather than single sectors based on
the full and effective participation of indigenous and local communities.
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6.4.2 Social, economic and cultural considerations of Solar Radiation Management
techniques
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As with climate change, solar radiation management is expected to impact weather patterns
with implications for ecosystem productivity and associated livelihoods. Any shifts of
temperature and changes to the hydrological cycle might affect local and indigenous
communities, especially those dependent on provisioning ecosystem services such as food,
energy. Cultural services such as ceremonies that follow planting and harvesting seasons in
most rain fed agricultural regions (e.g. Nigeria and Ghana302,303) could also be affected by
rapid changes in hydrological regimes.
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On the other hand, since SRM theoretically has the potential to target regional climatic
changes304 (for example, in the Arctic), local approaches may address climate change
sufficiently to preserve threatened traditional livelihoods. However, a number of uncertainties
regarding the impact of SRM for instance on food security, ecosystem productivity and
associated issues remain. Some approaches suggest changing the albedo of agricultural land,
and it is unknown what the impact will be on productivity305. As another example, some
projected increases in crop productivity due to changes in diffuse insolation306 are expected
300
Secretariat of the Convention on Biological Diversity. (2009) (a). Connecting Biodiversity and Climate Change
Mitigation and Adaptation: Report of the Second Ad Hoc Technical Expert Group on Biodiversity and Climate
Change. Montreal, Technical Series No. 41, 126 pages.
301 UNEP/CBD/SBSTTA/16/INF/30: Impacts of climate related geo-engineering on biodiversity: views and
experiences of indigenous and local communities and stakeholders.
302
Orkwor, G. C., Asiedu, R. and I. J. Ekanayake, 1998. Food Yams. Advances in Reasearch. IITA and NRCRI,
Nigeria, 249 pp.
303 IITA 2010. Research to nourish Africa. R4D Review. http://r4dreview.org/2010/04/yam-festival.
304 Rasch, P.J., Latham, J., and C.C. Chen. (2009). Geoengineering by cloud seeding: influence on sea ice and
climate system. Environmental Research Letters, Volume 4, Pages 1-8.
305 Ban-Weiss, G.A. and K. Caldeira (2010). Geoengineering as an optimization problem. Environmental Research
Letters, Volume 5, Pages 1-9.
306 Keith, D.W. (2010). Photophoretic levitation of engineered aerosols for geoengineering. PNAS Volume 107,
pages 16428-16431.
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although this increase may be either offset or enhanced by regional changes in precipitation
which will impact rainfed agriculture and traditional pastoral livelihoods with effects likely to
be positive in some areas and negative in others 307,308.
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Stratospheric aerosols would adversely affect ground-level astronomical observation and as
well as satellite-based remote sensing of Earth. They may also make skies whiter (less blue)
though the expected magnitude of this effect is not clear309.
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6.4.3 Social, economic and cultural considerations of Land Based Carbon Dioxide
Removal techniques
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Land based CDR poses uncertain impacts for ecosystem productivity and associated
livelihoods. Some models project increased ecosystem productivity310 which may lead to
increased food production while increased carbon and nutrient content in soils may increase
yields311 although the long term impacts are unknown.
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The large-scale implementation of “artificial trees” could compromise locally significant
features, or degrade whole culturally significant landscapes and with possible parallels to the
debate over wind farms. These are also likely to be associated with noise associated with wind
currents or machinery, depending on the deployment. Concerns have also been raised on
about whether CDR-interventions of this form could deplete local freshwater supplies, and
negatively impact local freshwater biodiversity.
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Large-scale afforestation also implies changes on landscapes that are likely to have both
positive and negative impacts on biodiversity, ecosystems services and their uses. Besides
from the possibility of competing land uses (mentioned above), altered landscapes imply
habitat fragmentation and/or loss. Some of these concerns could also apply to reforestation in
certain circumstances.
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Furthermore, it has been suggested that some land based CDR approaches could make use of
genetic modification of organisms and / or monoculture hybrid crop breeding312 which may
have a negative impact on traditional crop varieties and non-target species including those of
cultural / medicinal importance. Where such approaches are considered, the safe handling of
such materials, including through the provisions set out in the Cartagena Protocol on
Biosafety313 apply.
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6.4.4. Social, economic and cultural considerations of Ocean Based Carbon Dioxide
Removal techniques
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The impacts of ocean based CDR are likewise faced with regional disparities and
uncertainties. Some activities to enhance ocean alkalinity could negatively impact marine and
coastal species of cultural importance, other impacts, such as disruptions to fisheries due to
changes in marine food chains, are likely to be positive in some areas and negative in
307
Latham, J., Rasch, C., Chen C., Kettles, L., Gadian, A., Gettelman, A., Morrison, H. and K. Bower. (2008).
Global temperature stabilixation via controlled albedo enhancement of low-level maritime clouds. Philosophical
Transactions fo the Royal Society A, Volume 366, Pages 3969-3987.
308 Ridgwell, A. and J.S. Singarayer. (2009). Tackling Regional Climate Change by Leaf Albedo Bio-engineering.
Current Biology, Volume 19, Pages 146-150.
309
Solar radiation management: the governance of research. The Royal Society.
http://www.srmgi.org/files/2012/01/DES2391_SRMGI-report_web_11112.pdf
310 Woodward,
I., Bardgett, R.D., Raven, J.A., and A.M. Hetherington. (2009). Biological Approaches to Global
Environment Change Mitigation and Remediation. Current Biology, Volume 19, Issue 14, R615-R623.
311 The Royal Society (2009). Geoengineering the climate. Science, governance and uncertainty. London, 82 pages.
312 Vandana Shiva, 1993, Monocultures of the Mind: Perspectives on Biodiversity and Biotechnology, Third World
Network, Penang, Malaysia.
313 Cartagena Protocol on Biosafety. http://bch.cbd.int/protocol/
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others314. In addition, some consequences of ocean fertilization can have unpredictable far
field effects, so distant ecological and human communities can be affected. There is also a
suggested risk of toxic blooms but ocean fertilization is probably a less significant driver
compared to others such as land-based nutrient inputs.
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314
Secretariat of the Convention on Biological Diversity. (2009) (b). Scientific Synthesis of the Impacts of Ocean
Fertilization on Marine Biodiversity. Montreal, Technical Series No. 45, 53 pages.
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CHAPTER 7. SYNTHESIS / CONCLUDING REMARKS
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This study has reviewed the range of geo-engineering techniques (Chapter 2), reviewed the
projected impacts of climate change on biodiversity (Chapter 3) and also considered the
impacts of geo-engineering techniques on biodiversity (Chapters 4 and 5). Based on the
information in those chapters, this chapter (section 7.1) provides a concise review of how the
drivers of biodiversity loss under the scenarios of (i) rapid and significant reduction in
greenhouse gas emissions; and (ii) deploying geo-engineering techniques to address climate
change, against a baseline scenario of taking no action to reduce climate change.
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Also as noted, at a global scale, the largest driver of terrestrial biodiversity loss has been, and
continues to be, land use change. In the oceans, overexploitation has also been a major cause
of loss. Climate change is rapidly increasing in importance as a driver of biodiversity loss.
However, the drivers of loss vary among ecosystems and from region to region.
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In the baseline scenario described in Chapter 3, that is, in the absence of action to reduce
greenhouse gas emissions, climate change poses an increasingly severe range of threats to
biodiversity and ecosystem services resulting from changes in temperature, precipitation and
other climate attributes, as well as the associated phenomenon of ocean acidification. The
impacts are exacerbated by the other anthropogenic pressures on biodiversity (such as overexploitation; habitat loss, fragmentation and degradation; the introduction of non-native
species; and pollution) since these reduce the opportunity for gradual vegetation shifts,
population movements and genetic adaptation. In addition, climate change is projected to
actually increase some of the other drivers, for example by providing additional opportunities
for invasive alien species.
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Under this baseline scenario of taking no action to address climate change, the climate change
driver will increase substantially.
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Under the scenario of addressing climate change through a rapid and significant reduction in
greenhouse gas emissions, there would be a transition to a low-carbon economy in both the
way we produce and use energy and the way we manage our land. Measures to such effect
could include: increased end use efficiency; the use of renewable energy technologies
alongside nuclear and carbon capture and storage; and ecosystem restoration and improved
land management. These measures would substantially reduce the adverse impacts of climate
change on biodiversity. Generally, most other impacts on biodiversity, mediated through other
drivers, would be small (e.g. use of nuclear power to replace fossil fuels) or positive (e.g.
avoided deforestation, ecosystem restoration). Although some of the climate change
mitigation measures have potential negative side-effects on biodiversity (e.g. bird kill by wind
farms; disruption of freshwater ecosystems by hydropower schemes) these can be minimized
by careful design. Overall, climate change mitigation measures are expected to be beneficial
for biodiversity and the provision of ecosystem services.
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Under this scenario therefore, the climate change driver will be very much reduced. Land use
change would also likely be significantly reduced relative to the baseline scenario. Pollution
and invasive species are expected to be somewhat reduced compared to the baseline, while
there are few reasons to expect significant differences in overexploitation.
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A third scenario involves deploying geo-engineering techniques to address climate change in
the absence of significant emission reductions. Under such a scenario, some of the negative
The chapter also includes remarks on the importance of scale (section 7.2) and highlights key
areas where further knowledge and understanding is required (Section 7.3)
7.1. Changes in the drivers of biodiversity loss
As noted in Chapter 1, the direct drivers of biodiversity loss are habitat conversion, overexploitation, the introduction of invasive species, pollution and climate change.
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impacts of climate change on biodiversity could be reduced, provided that the techniques
prove to be feasible and effective. At the same time, most geo-engineering techniques would
have potential negative impacts on biodiversity. The net effect on biodiversity will vary
depending on the techniques employed and are difficult to predict. The techniques are
associated with significant risks and uncertainties.
Under this scenario, the climate change driver would be expected to be significantly reduced,
compared to the baseline scenario of taking no action, for some or all aspects of climate
change and/or their impacts. For several techniques (e.g. surface albedo and afforestation)
there would likely be increases in land use change compared to the baseline scenario, though
this driver would likely be unaffected for some other techniques. For some techniques (e.g.
afforestation) there could be an increased risk from invasive species compared to the baseline,
though this could be avoided through good design. Some other techniques (e.g. aerosols,
ocean fertilization) may lead to a small increase in pollution compared to the baseline. There
are few reasons to expect significant differences in overexploitation compared to the baseline
scenario.
7.2. The question of scale and its implications for feasibility and impacts of geoengineering techniques
The study describes a large range of potential impacts of geo-engineering techniques on
biodiversity and large uncertainties associated with these. To have a significant impact on
reducing climate change, geo-engineering techniques need to be deployed on a large scale,
either individually, or in combination. In most cases the risks associated with the techniques
are very much dependent upon the scale at which they are deployed. In fact, some of the
techniques (e.g. whitening of the built environment; afforestation; biomass production) are
benign at a small scale, but scaling up is either difficult or impractical (e.g. spatial extent of
the built environment is limited) or associated with large negative effects (afforestation – as
opposed to reforestation – or biomass production on a very large scale could have significant
adverse effects on biodiversity via land-use change).
7.3. Gaps in knowledge and understanding
The report recognizes many areas where knowledge is still very limited. These include (i)
how will the proposed geo-engineering techniques affect weather and climate regionally and
globally; (ii) how do biodiversity and ecosystems and their services respond to changes in
climate; (iii) the direct effects of geo-engineering on biodiversity; and (iv) what are the social
and economic implications.
In addition, there is very limited understanding among stakeholders of geo-engineering
concepts, techniques and their potential impacts on biodiversity. There is also as yet little
information on the perspectives of indigenous peoples and local communities and other
stakeholder on geo-engineering, especially in developing countries. Considering the role these
communities play in actively managing ecosystems, this is a major gap.
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ANNEX I. SUMMARY OF SELECTED DEFINITIONS OF CLIMATE-RELATED GEOENGINEERING
1. Convention on Biological Diversity – Decision X/33
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Technologies that deliberately reduce solar insolation or increase carbon
sequestration from the atmosphere on a large scale that may affect biodiversity
(excluding carbon capture and storage from fossil fuels when it captures carbon
dioxide before it is released into the atmosphere)
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http://www.cbd.int/climate/doc/cop-10-dec-33-en.pdf
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2. Intergovernmental Panel on Climate Change – Fourth Assessment Report
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Technological efforts to stabilize the climate system by direct intervention in the
energy balance of the Earth for reducing global warming
http://www.ipcc.ch/pdf/glossary/ar4-wg3.pdf
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3. Intergovernmental Panel on Climate Change – Third Assessment Report
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Efforts to stabilize the climate system by directly managing the energy balance of the
Earth, thereby overcoming the enhanced greenhouse effect
http://www.ipcc.ch/pdf/glossary/tar-ipcc-terms-en.pdf
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4. The United Kingdom of Great Britain and Northern Ireland
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Activities specifically and deliberately designed to effect a change in the global
climate with the aim of minimising or reversing anthropogenic (that is, human made)
climate change
http://www.publications.parliament.uk/pa/cm200910/cmselect/cmsctech/221/22102.htm
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5. The United Sates House of Representatives Committee on Science and Technology
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The deliberate large-scale modification of the Earth’s climate systems for the
purposes of counteracting [and mitigating anthropogenic315] climate change
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Hearing on November 5th, 2009 - Geoengineering: Assessing the Implications of
Large-Scale Climate Intervention
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6. The Royal Society
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The deliberate large-scale manipulation of the planetary environment to counteract
anthropogenic climate change
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Geoengineering the Climate: Science, governance and uncertainty. September, 2009
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7. The National Academy of Science
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Options that would involve large-scale engineering of our environment in order to
combat or counteract the effects of changes in atmospheric chemistry
Added in the Report by the Chairman of the Committee on Science and Technology ‘Engineering the Climate:
Research Needs and Strategies for International Coordination – October, 2010’.
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http://books.nap.edu/openbook.php?record_id=1605&page=433
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8. The Australian Academy of Science
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A branch of science which is focused on applying technology on a massive scale in
order to change the Earth's environment
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http://www.science.org.au/nova/123/123key.html
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9. The ETC Group (Non-governmental Organization)
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Intentional, large-scale manipulation of the environment by humans to bring about
environmental change, particularly to counteract the undesired side effects of other
human activities
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http://www.etcgroup.org/en/materials/issues
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10. The Asilomar Conference Report: Recommendations on Principles for Research into
Climate Engineering Techniques
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Deliberate steps to alter the climate, with the intent of limiting or counterbalancing
the unintended changes to the climate resulting from human activities.
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http://www.climateresponsefund.org/images/Conference/finalfinalreport.pdf
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