Updated LCA Climate Metrics
Presentation at meeting of US TAG 207
August 4, 2014
Washington, D.C.
Tobias C. L. Schultz and Stanley Rhodes
SCS Global Services
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Public Discussion and Review of LCA Climate Metrics
LCA Climate Metrics are included in a publicly available draft ANSI standard,
which has completed its public comment period.
The metrics have separately been reviewed by industry, government, ENGOs,
and leading climate scientists, with widespread support.
Applications of the metrics have been presented to:

American Geophysical Union (December 2013).

UNEP-SETAC (Basel, 2014).

American Center for LCA (October 2013).

And others.
Metrics will be presented to presented to SETAC North America in November.
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The Global Climate
Cause-Effect Chain
based on IPCC AR 5
Scope of LCA
Characterization
1. Emissions released, human-caused
and natural
2. Increasing atmospheric
concentrations
3. Increases in global and regional
radiative forcing
4. Additional heat trapped in the Earthatmosphere system from integrated
radiative forcing
5. Increase in the Global Mean
Temperature (GMT)
6. Accelerating climate change as GMT
rises above key thresholds
7. Dangerous impacts to resources,
ecosystems, frequency and intensity
of extreme events, coastal areas.
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Environmental Relevance According to ISO 14044
ISO 14044 §4.4.2.2.2: “Environmental relevance encompasses a qualitative
assessment of the degree of linkage between category indicator results and category
endpoints: for example, high, moderate or low linkage.”
ISO 14044 recommends that indicators used in comparisons should be environmentally
relevant, and that environmental relevance should consider:

⎯ the condition of the category endpoint(s),

⎯ the relative magnitude of the assessed change in the category endpoints,

⎯ the spatial aspects, such as area and scale,

⎯ the temporal aspects, such as duration, residence time, persistence, timing, etc.,

⎯ the reversibility of the environmental mechanism, and

⎯ the uncertainty of the linkages between the category indicators and the category endpoints.
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Selecting Environmentally Relevant Indicators
Environmental relevance is the
degree of linkage to endpoints,
considering both these sources of
uncertainty.
The most environmentally
relevant indicator is selected
subject to these constraints.
Uncertainty arising
from weakness of
linkage to endpoint
Node in cause effects chain
As one proceeds along the causeeffects chain, the relevance
increases, but the uncertainty in
measurement also increases.
Environmental
relevance
Uncertainty in
characterization
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Selecting the Environmentally Relevant Indicator for Global
Climate Change
Global Climate Change
1: Emissions released
2: Increasing atmospheric
concentrations
3: Increases in global and regional
radiative forcing
5: Increase in the Global Mean
Temperature
6: Accelerating climate change as
GMT exceeds key thresholds
7: Dangerous impacts to resources,
ecosystems, etc.
Nodal indicator selected
4: Additional heat trapped from
integrated radiative forcing
Integrated
radiative forcing
Environmental
relevance
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Radiative Forcing
The Earth is continually bathed in
radiative energy from the sun.
Upon entering the Earth’s atmosphere:
 Some sunlight is reflected (scattered)
 Some is absorbed in the atmosphere
 Some is absorbed by the Earth’s surface
 Some is reflected by the Earth’s surface
The Earth’s surface emits infra-red radiation:
 Some escapes into space
 Some is absorbed by the Earth’s atmosphere on its way out (the greenhouse effect)
Image source:
http://law.wlu.edu/deptimages/journal%20of%20energy,%20cli
mate,%20and%20the%20environment/Earth_Western_Hemisph
ere_white_background.jpg
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Radiative Forcing
Anomaly
Climate forcers warm or cool the Earth, by
absorbing or reflecting radiative heat.
Anthropogenic emissions have increased
concentrations of many climate forcers. These
forcers can:

Increase the amount of radiative heat
trapped (warming)

Increase the amount of sunlight
reflected (cooling)
Radiative forcing is a measure of the net
additional heat trapped by a climate forcer.
It is measured in Watts per meter squared
(W/m2), or milli-Watts per meter squared
(mW/m2). It can be positive or negative.
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Understanding the Effects from
Changes in Radiative Forcing
The Krakatoa volcanic eruption dropped Global
Mean RF by -3.4 W/m2, causing global
temperatures to drop by ~1°C for three years,
resulting in widespread crop losses and famine.
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Black Carbon: The Second Most Powerful Climate
Forcer (Global Mean RF =+1.1 W/m2)
Black Carbon Hot Spot over South Asia
• Δ RF =+12 W/m2
• Size = 1 million sq. km.
• Duration: Constant year-round
• Sources: Cooking fires, coal combustion
Radiative Forcing of Black and Brown Carbon (W/m2)
Source: Chung, C.E., V. Ramanathan, et al. 2005.
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Using Radiative Forcing to Develop Climate Metrics
GWPs are a measure of global mean
integrated radiative forcing, over a time
horizon.

GWPs have been established for all
types of climate forcers.
The updated metrics the GWP
measurement, but the factor is called the
Global Forcing Potential (GFP).
The IPCC AR5 notes that “Global Warming
Potential” can be a misleading term:

GWP does not consider
temperature, only forcing, and do
not consider coolants.
Global mean radiative forcing: mW / m2
This is compared to the integrated forcing
of CO2 over the same time horizon.
0.45
0.40
0.35
0.30
20
Years
0.25
0.20
100 Years
0.15
0.10
0.05
0.00
0
20
40
60
80
Years after emission of 1 million tons
Methane
100
Nitrous oxide
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Key Parameters in Assessing Integrated Radiative Forcing
Accounting for all climate forcers (both positive and negative
climate forcers).
Selecting the time horizons based on maximum temperature
targets.
Including indirect effects on the climate (e.g. for methane and
black carbon).
Developing characterization factors to account for regional and
source variability.
Using updated terminology.
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Key Features of the Updated
Climate Metrics
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LCA Metrics Include All Major Climate Forcers
(Total Global Net Forcing =+2.3 W/m2)
Kyoto Climate
Forcers list
(41%)
Carbon dioxide
Methane
Nitrous oxide
Radiative Forcing
(2011)
Short-Lived 1.8 W/mRadiative
Forcing
2
Climate Forcers
(2011)
2
(27%)
0.5 W/m
2
0.2 W/m
Cooling Climate
1.1
2
Other WMGHGsBlack carbon 0.3 W/m
Forcers
(CFCs, HCFCs, etc.)
Total
Brown carbon
(32%)
2
2.8 W/m
Tropospheric Ozone
Total
W/m2
0.3 W/m2
0.4 W/m2
Cooling aerosols
1.8 W/m2
(sulfate, nitrate,
and organics)
Radiative Forcing
(2011)
-2.1 W/m2
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+2°C
+1.5°C
+4°C
Targets are linked to Temperature Thresholds
Thresholds of increasing irreversibility
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Significance of these
Temperature Thresholds
Projected
Projected impacts
impacts when
when GMT
GMT
anomaly
anomaly reaches
reaches +2.0°C.
+4.0°C.
Even with global mitigation of all emissions, the
+1.5°C GMT anomaly will be exceeded.
+1.5°C Threshold (2035)
Possible point of Arctic
destabilization, and
projected loss of small island
states into the oceans.
+2.0°C Threshold (2050)
The point beyond which
dangerous climate
interference will occur,
according to international
consensus.
+4.0°C Threshold (2100)
This threshold is considered
by many scientists to be
“potentially catastrophic“.
The Alliance of Small Island States and 49 Least
In the
2009Countries
Copenhagen
Accord,
+2.0°C
was
Unprecedented
heat
extremes:
Julythat
in the
Developed
have
advocated
the
agreed
to asU.S.
the
maximum
temperature
target. 1.5°C
central
will
be 9°C
(20°F)
warmer
+1.5°C
be
selected
as
the
maximum
3 feet
ofasea
level
rise
The
United
States
was
party
to
thisagreements.
agreement.
temperature target under UNFCCC
1900
1950
Significant declines in
food production in all
Coral reefs decimated
world regions.
by bleaching.
2000
2050
to an
water
,
AsEffects
much as
80%supplies
reduction
including
a 40%
reduction
in surface
water
in the in
surface
water River
supplies
in the
Mississippi
Basin.
Mississippi River Basin.
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Potential Consequences of the +4.0°Temperature Threshold
+4.0°C: last
exceeded 25
millions years ago
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Complete Accounting Reveals New
Mitigation Opportunities
Current metrics hide potential of
projects for reducing black carbon
emissions.
“Dangerous” warming per
Copenhagen Accord
They underestimate the benefit of
projects to reduce methane
emissions.
As discussed, these types are projects
are necessary to avoid exceeding
+2°C.
1900
1950
2000
2050
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Including Short Lived Climate
Forcers (SLCFs)
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IPCC Established
GWPs for SLCFs
IPCC AR5 report synthesizes
the consensus science on
GWPs for SLCFs.
Includes global average values
for black and organic carbon,
and regionally differentiated
values for NOx.

Values for black carbon
must be updated to account
for regional variability in
forcing.
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Accounting for Regional Variability of Black Carbon
Accounting must consider the region of
emission.

The GWP of black carbon can vary by
30% or more, based on the region of
emission.
Radiative Forcing of Black and Brown Carbon (W/m2).
Source: Chung, C.E., V. Ramanathan, et al. 2005.
The type of source of an emission is
also very important.

The GWP for black carbon from
biomass combustion is about 50%
higher than the GWP for diesel fuel
combustion.
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Calculating Regional GWP Values for Black
Carbon Using Consensus Science
Three radiative effects of black carbon:

“Direct” effect: darkened atmosphere absorbs
more sunlight.

Snow and ice effects: darkened surfaces absorb
more sunlight.

Cloud interactions: Cloud distributions,
structure, and presence are altered by black
carbon inside and outside the cloud.
Applying the framework, findings from consensus climate
science undergo a data quality assessment to establish GWP
values for black carbon.
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The Importance of Sulfate Cooling
IPCC AR5 estimates that cooling from sulfates today masks 75% of
the radiative forcing caused by CO2.
Since 1800, sulfate cooling has mitigated 30-50% of global
warming.
 It has
masked more than 50% of the warming caused by the
United States.
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Tracking Global SO2 Emissions
2011: 85 million tons of sulfur emissions (MACEB, 2013)
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Three Major Cooling Zones from Anthropogenic
Sources (IPCC, 2001)
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Changes in SO2 Emissions Over Time
Since 1980:
60% decrease in emissions in USA and Europe
300% increase in China
Source: Smith, et al. 2011.
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Mapping Trends: US Sulfate Cooling Zones have
Dissipated
1999 Sulfate Cooling Zone
2009 Sulfate Cooling Zone
Regional Cooling = -4.0 W/m2
Regional Cooling = -1.0 W/m2
According to Harvard and NASA research (2011), this loss in sulfate
cooling has raised regional mean temperatures by over +1oC.
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LCA Characterization Modeling:
Sharp Increase in the Chinese Sulfate Cooling Zone (1978-2008)
1978 Sulfate Cooling Zone
2008 Sulfate Cooling Zone
Regional Cooling = -1.0 W/m2
Regional Cooling = -8.0 W/m2
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The Increase in Chinese Cooling was a Major
Reason for Pause in the Rise of GMT (2000-2008)
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Health Impacts Associated with Chinese Sulfate
Cooling Zone
Trade-off: Lung cancer rates have doubled
in China, and asthma now affects 30% of
children in the region.
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Implications of Dissipation of Chinese Sulfate Cooling Zone
?

IPCC AR5 projections do not include significant reductions in SO2 emissions in China.

China is working to reduce emissions from coal power plants and other industries. Since
AR5 was published, China has invested $350 billion to reduce SO2 emissions.

An unintended consequence would be an immediate increase in global forcing.
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Establishing GFP Values for
the Three Temperature
Thresholds
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Applying the Global Temperature
Thresholds in Practice
The Global Warming Potential (GWP) equation, defined by IPCC, is used. Any one
of three time horizons can be used, each with different implications:
1.5°C threshold: 20-year time horizon.
Use of this threshold focuses on near-term mitigation options, such as mitigation
of short-lived climate forcers.

2°C Threshold: 35-year time horizon.
Use of this threshold focuses on mitigation options targeted at averting major
irreversible climate change.

4°C Threshold: 100-year time horizon.
Use of this threshold focuses on mitigation of emissions of long-lived GHGs.

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Basis of Global Forcing Potentials
The updated climate metrics are
not based in original research.



IPCC AR5 Chapter 8 has metric
values for all of the GHGs, most
of which can be used without
change. However, some of
these values must be updated.
Establishment of GFPs is wellestablished in the peerreviewed literature.
GFP values are based on
published findings.
The climate metrics assimilate
published data into a single
unified framework.
Example data sources:

Chapter 8 of IPCC AR5

Collins, et al. (2013). Global and regional temperature-change potentials for
near-term climate forcers. Atmos. Chem. Phys., 13, 2471-2485, 2013.

Shindell, D.T., (2009). Improved Attribution of Climate Forcing from Emissions.
Vol. 326, 716-718. Science, October 2009.

Joos, F., et al (2013). Carbon dioxide and climate impulse response functions for
the computation of greenhouse gas metrics: a multi-model analysis, Atmos.
Chem. Phys., 13, 2793-2825, doi:10.5194/acp-13-2793-2013, 2013.

Reisinger, A., M. Meinshausen, M. Manning, and G. Bodeker (2010),
Uncertainties of global warming metrics: CO2 and CH4 , Geophys. Res. Lett., 37,
L14707, doi:10.1029/2010GL043803.

Bond, T. C., et al. (2013), Bounding the role of black carbon in the climate
system: A scientific assessment, J. Geophys. Res. Atmos., 118, 5380–5552,
doi:10.1002/jgrd.50171.

Bond, T., et al. Quantifying immediate radiative forcing by black carbon and
organic matter with the Specific Forcing Pulse. Atmos. Chem. Phys., 11, 15051525, 2011.
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Global Forcing Potentials by Temperature Threshold
Climate Forcer
+1.5°C threshold
(Next 20 years)
+2.0°C threshold
(Next 35 years)
+4.0°C threshold
(Next 100 years)
Carbon dioxide
From IPCC AR5
1
1
1
Nitrous Oxide
From IPCC AR5
264
280
265
Methane
104
73
32
-313
-196
-85
From Bond 2011 and 2013
2,525
1,608
717
Black carbon (South Asia,
biomass)
3,625
2,308
1,030
From Shindell 2009
SO2 -> Sulfate aerosols
From Collins, 2013
Black carbon (U.S, energy)
From Bond 2011 and 2013
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Updating the GWP of
Methane
The climate effects of methane are
complex:
IPCC has updated the GWP for methane,
including one additional effect.
Substance
GWP-20
GWP-100
Commonly used GWP value (23)
Methane
Absorbs infrared radiation directly only
86for one effect
34 over
(IPCCaccounts
AR5)
100 years
NASA scientists have assessed
Effects plant growth
On decay, forms ozone and CO2
Forms stratospheric water vapor
Decreases sulfate aerosol cooling
estimates including all other effects,
resulting in even higher values.
Substance
GWP-20
Methane
104
(Shindell 2009)
GWP-100
32
The metrics include all climate effects of
methane for which accurate data is
available.
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Outputs of Updated Climate Metrics
Climate Forcing Profiles

Represents net forcing over the
next 100 years

Measured in units of milli-Watts
per square meter, in each year

Used to understand changes in
radiative forcing over time

Through integration, can be used to
calculate Climate Footprints
Climate Footprints

Evaluate the net integrated
forcing out to one of the three
GMT anomaly thresholds

Measured in units of kg CO2e

To be used as the basis of any
LCA comparisons
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Applying Climate Metrics to a Refrigerator
• 14 years of use in
Georgia, US
• 477 kWh/yr.
• Made in China
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Refrigerator Climate Footprint Changes over Time
Coal power plant in Inner Mongolia
2035 Climate Footprint = 9,900
kilograms
80
70
Forcing 10-9 mW m-2
60
2050 Climate Footprint = 7,900
Emissions
of short-lived
kilograms
forcers during manufacture
50
40
30
Emissions of CO2 from use
accumulate over 14 years
20
Long-lived gases remain in
2100 Climate Footprint = 7,700
atmosphere
for 100+ years
kilograms
China is one of the world’s largest
emitters of black carbon!
10
0
0
10
20
30
40
50
60
Years After Manufacture
70
80
100+
years
90
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Changes in Climate Footprint Based on
Manufacturing Location
2035 Climate Footprint
(kg CO2e)
Refrigerator
Made in China
Refrigerator
Made in USA
5,700
800
Use
(US-14 years)
4,200
4,200
Total
9,900
4,900
Manufacturing
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American VS Chinese
Manufacturing
(Based on 2035 Climate Footprint)
LCA Scope
(per 1,000,000
units)
Manufacturing
Use
(US-14 years)
Refrigerator
Made in
China
(tons CO2e)
Refrigerator
Made in USA
(tons CO2e)
Potential Impact
Reductions
5.7 million
0.8 million
Switching site of
manufacture
4.2 million
4.2 million
25% efficiency
improvement
5M tons
1M tons
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Conclusions
The updated climate metrics should include:

Factor in internationally-agreed upon maximum temperature targets.

Include all climate forcers, including black carbon.

Accurately account for the forcing effects of methane.

Account for effects from coolants.

Complete LCA information output: Calculating Climate Forcing Profiles and
three changes in the Climate Footprint over the three critical time horizons.
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Questions? Please Contact:
Tobias Schultz, Life Cycle Assessment Practitioner
SCS Global Services
tschultz@scsglobalservices.com
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