Climate Change 101
An Educational Resource
Science – Impacts – Adaptation –
Mitigation – Decision-making Challenges
Andy Reisinger
Institute of Policy Studies
and New Zealand Climate Change Research Institute
Published in 2009
Institute of Policy Studies
and
New Zealand Climate Change Research Institute
School of Government
Victoria University of Wellington
PO Box 600
Wellington
© Institute of Policy Studies
http://ips.ac.nz
ISBN 978-1-877347-34-4 (print)
ISBN 978-1-877347-36-8 (online)
IPS/Pub/164
This book is copyright. Apart from any fair
dealing for the purpose of private study,
research, criticism, or review, as permitted
under the Copyright Act, no part may be
reproduced without the permission of
the relevant copyright holder.
Copy editors: Belinda Hill and Jenny Heine
Cover design: Andy Reisinger. Photographs: iStock.com.
The image of the Earth is owned and provided by the US National Aeronautics
and Space Administration (NASA), available from http://visibleearth.nasa.gov.
Printed by Milne Print
For Lukas
who will have to live through
what for us remain just abstract scenarios
Contents
List of Boxes ..........................................................................................................................vii
List of Figures ......................................................................................................................viii
List of Tables...........................................................................................................................x
Foreword ................................................................................................................................xi
Acknowledgements ..............................................................................................................xiii
Introduction ............................................................................................................................1
1
Taking Stock of a Warming World ..........................................................................11
1.1
Introduction – definitions of ‘climate’ and ‘climate change’ ..........................12
1.2
Changes in the climate system.........................................................................13
1.3
Comparing the 20th century climate with the climate in earlier times............22
1.4
Impacts of observed changes in the climate system ........................................25
1.5
Direct effects of increasing carbon dioxide concentrations.............................33
2
Do We Understand What Is Driving Climate Change?..........................................35
2.1
Understanding Earth’s energy balance – a brief history..................................36
2.2
Cause of rising greenhouse gas concentrations ...............................................40
2.3
Changes in Earth’s energy balance..................................................................44
2.4
Attribution of observed climate change...........................................................50
2.5
Attributing observed impacts of climate change .............................................58
3
Climate Projections for the Future ...........................................................................61
3.1
Introduction .....................................................................................................62
3.2
Emissions scenarios.........................................................................................63
3.3
Climate projections until the end of the 21st century......................................68
3.4
Twenty-first century projections – summary and historical perspective.........82
3.5
Climate change beyond the 21st century.........................................................84
3.6
Feedbacks and potential for rapid changes in the climate system ...................89
4
Impacts of Projected Climate Changes ....................................................................97
4.1
Introduction .....................................................................................................99
4.2
Water .............................................................................................................101
4.3
Ecosystems ....................................................................................................106
4.4
Food supply ...................................................................................................110
4.5
Coastal zone...................................................................................................115
4.6
Health ............................................................................................................118
4.7
Settlements and society .................................................................................122
4.8
Extreme events ..............................................................................................126
4.9
Severity and extent of impacts as a function of temperature.........................129
4.10 Regional distribution of impacts and especially affected regions .................131
v
5
Increasing Resilience: Potential for adaptation.....................................................135
5.1
Introduction ...................................................................................................136
5.2
Historic adaptations and their lessons for the future .....................................137
5.3
Multiple stresses ............................................................................................139
5.4
Adaptation options, policies, costs, and effectiveness...................................141
5.5
Adaptive capacity, and barriers and limits to adaptation...............................148
6
Reducing the Pressure: Potential for mitigation ...................................................155
6.1
Climatic benefits of reducing greenhouse gas emissions ..............................157
6.2
The challenge of rising emissions .................................................................160
6.3
Global economic potential for mitigation......................................................166
6.4
Sector-specific mitigation options, potentials, policies, and barriers ............172
6.5
Policies to support mitigation........................................................................202
6.6
Behaviour and lifestyle choices.....................................................................207
7
Stabilising Greenhouse Gas Concentrations..........................................................209
7.1
Stabilisation scenarios and long-term climate change...................................210
7.2
Technologies to support stabilisation ............................................................214
7.3
Carbon prices and macroeconomic costs of mitigation.................................219
8
Putting it Together: Climate change as a risk management problem .................227
8.1
Framing the problem .....................................................................................228
8.2
Key vulnerabilities.........................................................................................231
8.3
Timescales and pathways for mitigation to achieve a stable climate ............236
8.4
Cost–benefit perspective – costs of mitigation and avoided damages...........242
8.5
Regional and country-specific differences ....................................................249
9
Climate Change and Development: Friends or foes?............................................253
9.1
Introduction ...................................................................................................254
9.2
Impact of climate change on development opportunities ..............................255
9.3
Links between adaptation and sustainable development ...............................257
9.4
Influence of socioeconomic trends and sustainable development policies
on future greenhouse gas emissions ..............................................................261
9.5
Influence of mitigation actions on socioeconomic development...................264
9.6
Interaction of mitigation and adaptation options ...........................................267
9.7
Conclusions on development and climate change responses ........................269
10
Global Response and Challenges for the Future ...................................................271
10.1 The long road from a scientific discovery to a political response .................272
10.2 United Nations Framework Convention on Climate Change and Kyoto
Protocol, and other international activities ....................................................274
10.3 Basic tensions and challenges for future agreements ....................................282
10.4 The road ahead ..............................................................................................293
References............................................................................................................................295
vi
Boxes
1.1
1.2
1.3
1.4
1.5
1.6
2.1
2.2
2.3
2.4
3.1
3.2
3.3
3.4
3.5
4.1
4.2
4.3
4.4
5.1
5.2
5.3
6.1
6.2
6.3
7.1
7.2
8.1
8.2
9.1
10.1
10.2
Limitations of proxies for deriving pre-20th century climate information .....................23
Effect of changes in sea-ice cover on Antarctic penguins............................................27
Effect of algal bloom events on freshwater ecosystems...............................................28
Impact of higher temperatures on terrestrial species and ecosystems ..........................29
Coral bleaching – role of increasing temperatures and other pressures .......................30
The difficulty of identifying economic impacts of climate change..............................32
What determines the concentrations of greenhouse gases in the atmosphere? ...............43
Climate models – can they reproduce and explain real climate change? .....................51
Can we attribute individual storms and other extremes to human causes? ..................58
Recent studies investigating the causes for changes in rainfall and Arctic sea ice ......59
Carbon dioxide equivalent emissions and concentrations............................................65
Timescales in responses of the climate system ............................................................70
Regional climate patterns: potential changes in monsoons and El Niño ........................74
Potential contributions of ice sheets to sea-level rise by 2100 – recent studies ...........80
The ‘known unknowns’ of Greenland’s future beyond 2100.......................................89
Importance of seasonal changes in water supply in India ..........................................102
Ocean acidification.....................................................................................................110
Carbon dioxide fertilisation – how far can it boost plant growth? .............................114
Small islands – at the squeeze from coastal and other pressures................................118
Reducing vulnerability of corals to climate change by reducing other stresses .........140
Benefits of and reservations against ‘mainstreaming’ adaptation ..............................144
Adaptation in ecosystems ...........................................................................................152
Will rising oil prices automatically lead to lower greenhouse gas emissions?...........165
Biofuels – opportunities and challenges in a global context ......................................194
Carbon prices and what they mean in everyday life...................................................203
Hydrogen’s role in a low-carbon energy system........................................................217
Key assumptions in modelling studies on mitigation costs and carbon prices...........222
Key vulnerabilities, temperature and concentration targets .......................................235
Assumptions and judgements in estimating the cost of climate change .......................244
Millennium Development Goals and targets..............................................................256
Growth of scientific knowledge as represented in IPCC assessment reports.............273
Recent emission trends and implications for low-level stabilisation options.............290
vii
Figures
1.1
Trend and inter-annual variability in global average surface temperature,
1850–2006....................................................................................................................15
1.2 Linear trend of annual average temperatures in different parts of the globe,
1901–2005....................................................................................................................16
1.3 Arctic sea ice extent in 1982, 2005, and 2007, and median ice extent over
1979–2000....................................................................................................................18
1.4 Global average change in sea levels, relative to the average sea level over
1961–1990....................................................................................................................21
1.5 Changes in average northern hemisphere temperatures over the past 1,300 years ......24
1.6 Map of observed changes in physical and biological systems correlated with
temperature changes, 1970–2003 .................................................................................33
2.1 Schematic illustration of the Earth’s energy balance ...................................................39
2.2 Atmospheric concentrations of carbon dioxide, methane, and nitrous oxide over
the past 10,000 years and since 1750 ...........................................................................41
2.3 Relationship between emissions and concentrations of short- and long-lived
greenhouse gases ..........................................................................................................44
2.4 Global average radiative forcing in 2005 relative to 1750 from human and natural
causes ...........................................................................................................................49
2.5 Observed and model-simulated pattern of average annual precipitation,
1980–1999....................................................................................................................52
2.6 Comparison of observed and modelled warming for land, ocean, and the world as
a whole .........................................................................................................................55
3.1 Scenarios of future carbon dioxide equivalent (CO2-eq) global greenhouse gas
(GHG) emissions, 2000–2100......................................................................................65
3.2 Projections of greenhouse gas emissions, concentrations, and temperature change,
2000–2100....................................................................................................................69
3.3 Global pattern of warming, 2090–2099........................................................................72
3.4 Changes in seasonal average precipitation projected in 2090–2099 relative to
1980–1999....................................................................................................................73
3.5 Changes in extremes as a result of changes in mean climate .......................................76
3.6 Projected changes in rainfall and snowfall intensity, dry days, and heat waves
over the 21st century ....................................................................................................78
3.7 Global pattern of sea-level rise at the end of the 21st century .....................................81
3.8 Projected increases in global average temperature compared to historical
temperature changes .....................................................................................................83
3.9 Simulated long-term warming under two emissions scenarios ....................................85
3.10 Modelled reduction of Greenland ice sheet under elevated temperatures....................88
3.11 Global carbon cycle and its links to the climate system...............................................91
3.12 Meridional overturning circulation (MOC) in the North Atlantic and possible
influences of climate change ........................................................................................93
4.1 Changes in run-off in different world regions, 2090–2099 relative to 1980–1999 ....103
4.2 Projected changes in maize, wheat, and rice yield at different latitudes ....................113
4.3 Natural and human influences on the coastal system .................................................116
4.4 Pathways of climate change impacts on human health ..............................................119
4.5 Impacts of 2003 European heat wave on mortality ....................................................120
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4.6
Economic impact of hurricane Mitch in 1998 and drought in 1998/99 on the
Honduran economy ....................................................................................................126
4.7 Schematic illustration of changes in extremes as a result of changes in mean
climate (reproduced Figure 3.5) .................................................................................127
4.8 Impacts associated with global average temperature change .....................................130
6.1 Emissions, concentrations, and temperatures for mitigation and non-mitigation
scenarios .....................................................................................................................159
6.3 Contributions of different sectors, processes, and gases to total greenhouse gas
emissions ....................................................................................................................162
6.4 Absolute and per capita greenhouse gas emissions and gross domestic product for
different world regions ...............................................................................................164
6.5 Effect of different carbon prices on global greenhouse gas emissions to 2030..........170
6.6 Economic mitigation potential for different sectors and world regions by 2030 .......171
6.7 Effect of combined mitigation options in reducing emissions from the electricity
sector, 2000–2030 ......................................................................................................184
6.8 Vehicle ownership as a function of per capita income for a range of countries.........186
6.9 Regional trends in emissions and sinks from forest-related activities since the
1850s ..........................................................................................................................197
6.10 Relationship between forest sector and other land uses and land-use services ..........198
6.11 Estimated annual rates of carbon placed in landfills, in megatonnes of carbon, in
different world regions, 1971–2002 ...........................................................................201
7.1 Emission pathways, stabilisation concentrations, and long-term temperature
change.........................................................................................................................211
7.2 Technological change in non-mitigation and stabilisation scenarios .........................215
7.3 Historical trends in research and development investment in energy research ..........220
7.4 Trends in global gross domestic product (GDP) growth with and without
mitigation measures....................................................................................................225
8.1 Inertia in the climate system: from emissions to sea-level rise ..................................237
8.2 Consequences of delay in emissions reductions for required reduction rates in
future decades.............................................................................................................239
8.3 Impacts of climate change on global gross domestic (GDP) product from different
studies.........................................................................................................................243
8.4 Distribution of estimates of the Social Cost of Carbon for the integrated damages
from greenhouse gas emissions ..................................................................................246
8.5 Relationship between costs of mitigation and climate change damages, and total
costs............................................................................................................................248
9.1 Effect of socioeconomic development on vulnerability to climate change................259
9.2 Global gross domestic product (GDP) and greenhouse gas emissions under
different socioeconomic scenarios .............................................................................262
10.1 World’s largest emitters and distribution of emissions across all countries in 2005..284
ix
Tables
2.1
Concentrations of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)
in pre-industrial and modern times...............................................................................42
3.1 Projected changes in temperature and sea level in 2090–2099 relative to
1980–1999 and 20th century observations ...................................................................82
4.1 Possible impacts due to changes in extreme weather and climate events.....................128
4.2 Examples of projected impacts on different world regions........................................132
5.1 Selected adaptation options in different sectors .........................................................142
6.1 Projected emissions increases under the range of Special Report on Emissions
Scenarios marker scenarios from 2000 to 2030, and economic mitigation
potential estimated from top-down and bottom-up studies for a range of
carbon prices...............................................................................................................170
6.2 Sector-wide and process-specific mitigation options for industry .............................183
7.1 Stabilisation scenarios and their long-term climate consequences.............................213
7.2 Estimated global macroeconomic costs for a range of stabilisation scenarios...........224
10.1 Key development indicators for selected developed and developing
countries/regions ........................................................................................................285
10.2 Emissions reduction targets for different country groupsa consistent with different
greenhouse gas concentration stabilisation levels ......................................................289
x
Foreword
Climate change is becoming increasingly recognised as the most important issue now
facing humanity. While some industry sectors are unhappy with the implications of
this, it is now widely accepted that the world will undergo enormous changes related
to climate in the next two generations. We must either rapidly modify energy
production systems, or accept major damaging changes in the global environment.
Following some intermediate compromise approach could blend the worst of those
two options.
Emissions of greenhouse gases are the key factor in global warming. There are
technical approaches to significantly reduce greenhouse gas emissions from energy
production, agriculture and deforestation, and so limit the amount of future climate
change. But ensuring that these are properly implemented is both technically
complex and politically challenging. Global action is required, but securing such
action is fraught with difficulty, not least because of concerns about national selfinterest and effort-sharing. Nevertheless, solving this global problem is the most
important issue that humanity has ever faced.
For the future of society it has become critical to develop a better and much
broader understanding of the causes of climate change, its effects, and the options for
mitigation and adaptation. The Intergovernmental Panel on Climate Change (IPCC)
was set up in 1988 to play a key role in developing a science-based understanding of
climate change issues in order to facilitate well-informed policy responses. It has
done this by regularly bringing together teams of experts from around the world to
assess the latest results from relevant scientific research and technical analyses. The
reports produced in this way provide authoritative and rigorous assessments of our
current knowledge, and the summaries are used in detail by policy-makers when
considering governmental responses.
However, those of us involved in preparing IPCC reports have become
increasingly aware that science also needs to be better communicated to members of
the public and not just to policy-makers. This is now more important than ever before
because of the need for public support for government plans to reduce greenhouse
gas emissions and the need to make such changes occur rapidly. It is increasingly
likely that future policy responses will be driven more by public opinion on climate
change than by scientific updates provided through the IPCC process.
Because of that background, Andy Reisinger’s summary of the science behind
our understanding of human causes of and responses to climate change, and of the
main findings from the most recent IPCC assessment published in 2007, is
particularly important. This book provides a clear, succinct, and measured summary
of our current knowledge of climate change, its potential impacts, and the scope for
reducing greenhouse gas emissions. It also explains the relevance of some of the
most recent scientific findings in a balanced way and highlights the urgency and
seriousness, as well as challenges, of dealing with climate change.
The book presents the relevant information in a style and format that is accessible
to a wide range of people. So it is valuable for those who want to know more about
the reasons for managing climate change and the need to address it as a matter of
urgency. It is also well designed to brief young students and researchers on the multidisciplinary issues underlying climate change, its causes, potential impacts, and the
range of responses that can mitigate these impacts. The next generation of people,
xi
Climate Change 101 – An Educational Resource
whether they are doing active research on climate change issues or involved in the
technical and social changes necessary to limit that change, will be critical for the
Earth’s future. This book is an important contribution to that.
Martin Manning
New Zealand Climate Change Research Institute
Victoria University of Wellington
Wellington
New Zealand
xii
Jonathan Boston
Institute of Policy Studies
Victoria University of Wellington
Wellington
New Zealand
Acknowledgements
I am heavily indebted to many individuals and agencies without whose support and
critical comments I would not have been able to conceive, write or complete this
book. First and foremost I wish to thank Martin Manning, who supported the concept
from the outset and provided financial assistance for my writing time through a
contract with the New Zealand Climate Change Research Institute, Victoria
University of Wellington. I also wish to thank the Ministry for the Environment,
particularly Phil Gurnsey, for funding the production of new graphics for this book,
and Andy Gray at GNS Science for turning my vague graphic concepts into reality.
The editing and printing of this book was supported by the New Zealand Climate
Change Research Institute and the director of the Institute of Policy Studies at
Victoria University of Wellington, Jonathan Boston, whose support I value deeply.
Belinda Hill and Jenny Heine did a splendid job in editing my manuscript and
rescued many obscure expressions from remaining unintelligible, and Maureen
Revell ensured the print production went smoothly.
My particular thanks in the writing of this book are due to Lenny Bernstein, who
not only provided meticulous comments on a draft of the entire book, but also
stepped into the breach to become co-author for chapter 6 (mitigation) when I was
becoming overwhelmed by the amount of material that needed to be covered. Many
other scientists provided helpful comments on various chapter drafts: Peter Bosch,
Ismail Elgizouli, Marilyn Head, Zbyszek Kundzewicz, Ulrike Lohmann, Martin
Manning, Neville Nicholls, Richard Nottage, Susan Solomon, Ron Stouffer, Peter
Stott and Gary Yohe. Their careful reading caught many errors and improved
readability, but I have not always followed my reviewers’ suggestions so, as always,
all remaining errors and subjective judgements about emphasis and balance are
entirely my own.
I would not have been able to contemplate, let alone write, this book if I had had
to sift through the tens of thousands of scientific papers that have been published
over the past few years on climate change, in disciplines ranging from statistics and
physics to ecology, psychology, and economics. Thankfully, I didn’t have to,
because this work has already been done by the many hundreds of scientists who
contributed to the Fourth Assessment Report of the Intergovernmental Panel on
Climate Change (IPCC) on which this book relies heavily as its main source. My
sincere thanks therefore go to all the scientists who contributed to that assessment
and previous assessments, which form the backbone of our knowledge about climate
change. Needless to say, any mistakes in this book are my responsibility, and not
those of the IPCC.
I also wish to thank the many colleagues who have supported and nurtured me in
various roles over the years. I have been lucky to work with outstanding scientists
and policy experts during my time as researcher with the National Institute of Water
and Atmospheric Research (NIWA), as senior adviser on climate change with the
Ministry for the Environment, as representative of the New Zealand government on
the IPCC, and as head of the Technical Support Unit for the production of the
Synthesis Report of the IPCC’s Fourth Assessment Report. In each of these roles, it
has been an enormous privilege to interact with extremely generous and openminded people who allowed me to learn from them and didn’t think twice about
giving up their personal time in response to a request for help or a curious question.
Thanks to all of you!
xiii
Climate Change 101 – An Educational Resource
Last but not least, I am grateful to my wife Veronika for bearing with me through
the writing process, and to our newborn son Lukas for reminding us that the year
2100 is not an abstract point in the distant future for climate change scenarios, but a
real year that he may well live to see. I only hope he’ll be happy with the planet we
leave him with.
xiv