Updated LCA Climate Metrics
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Transcript of Updated LCA Climate Metrics
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Updated LCA Climate Metrics
Presentation at meeting of US TAG 207 August 4, 2014
Washington, D.C.
Tobias C. L. Schultz and Stanley RhodesSCS 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 Chainbased on IPCC AR 5
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 Earth-atmosphere 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.
Scope of LCA Characterization
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Environmental Relevance According to ISO 14044
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.
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.”
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Uncertainty arising from weakness of
linkage to endpoint
Uncertainty in characterization
Selecting Environmentally Relevant Indicators
As one proceeds along the cause-effects chain, the relevance increases, but the uncertainty in measurement also increases.
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.
Node in cause effects chain
Environmental relevance
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Nodal indicator selected
1: Emissions released
2: Increasing atmospheric concentrations
3: Increases in global and regional radiative forcing
4: Additional heat trapped from integrated radiative forcing
5: Increase in the Global Mean Temperature
Global Climate Change
6: Accelerating climate change as GMT exceeds key thresholds
7: Dangerous impacts to resources, ecosystems, etc.
Selecting the Environmentally Relevant Indicator for Global Climate Change
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 atmos-
phere on its way out (the greenhouse effect)
Image source: http://law.wlu.edu/deptimages/journal%20of%20energy,%20climate,%20and%20the%20environment/Earth_Western_Hemisphere_white_background.jpg
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Radiative Forcing AnomalyClimate 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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Radiative Forcing of Black and Brown Carbon (W/m2) Source: Chung, C.E., V. Ramanathan, et al. 2005.
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
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0 10 20 30 40 50 60 70 80 90 1000.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
Methane Nitrous oxide
Years after emission of 1 million tons
Glo
bal m
ean
radi
ative
forc
ing:
mW
/ m
2
Using Radiative Forcing to Develop Climate MetricsGWPs are a measure of global mean integrated radiative forcing, over a time horizon.
This is compared to the integrated forcing of CO2 over the same 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.
100 Years
20 Years
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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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Kyoto Climate Forcers list (41%)
Radiative Forcing (2011)
Carbon dioxide 1.8 W/m2
Methane 0.5 W/m2
Nitrous oxide 0.2 W/m2
Other WMGHGs (CFCs, HCFCs, etc.)
0.3 W/m2
Total 2.8 W/m2
Short-Lived Climate Forcers (27%)
Radiative Forcing (2011)
Black carbon 1.1 W/m2
Brown carbon 0.3 W/m2
Tropospheric Ozone 0.4 W/m2
Total 1.8 W/m2
LCA Metrics Include All Major Climate Forcers (Total Global Net Forcing =+2.3 W/m2)
Cooling Climate Forcers(32%)
Radiative Forcing (2011)
Cooling aerosols (sulfate, nitrate, and organics)
-2.1 W/m2
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Targets are linked to Temperature Thresholds
+2°C
+1.5
°C
+4°C
Thresholds of increasing irreversibility
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Significance of these Temperature Thresholds
+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“.
Even with global mitigation of all emissions, the +1.5°C GMT anomaly will be exceeded.
Projected impacts when GMT anomaly reaches +2.0°C.
3 feet of sea level rise
Coral reefs decimated by bleaching.
Projected impacts when GMT anomaly reaches +4.0°C.
Significant declines in food production in all
world regions.
Effects to water supplies , including a 40% reduction in surface water supplies in the
Mississippi River Basin.
Unprecedented heat extremes: July in the central U.S. will be 9°C (20°F) warmer
As much as an 80% reduction in surface water in the Mississippi River Basin.
In the 2009 Copenhagen Accord, +2.0°C was agreed to as the maximum temperature target.
The United States was a party to this agreement.
2000 205019501900
1.5°C
The Alliance of Small Island States and 49 Least Developed Countries have advocated that the
+1.5°C be selected as the maximum temperature target under UNFCCC agreements.
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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.
They underestimate the benefit of projects to reduce methane emissions.
As discussed, these types are projects are necessary to avoid exceeding +2°C.
2000 205019501900
“Dangerous” warming per Copenhagen Accord
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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
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.
Radiative Forcing of Black and Brown Carbon (W/m2). Source: Chung, C.E., V. Ramanathan, et al. 2005.
Accounting must consider the region of emission.
The GWP of black carbon can vary by 30% or more, based on the region of emission.
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Calculating Regional GWP Values for Black Carbon Using Consensus ScienceThree 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 = -1.0 W/m2
According to Harvard and NASA research (2011), this loss in sulfate cooling has raised regional mean temperatures by over +1oC.
Regional Cooling = -4.0 W/m2
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LCA Characterization Modeling: Sharp Increase in the Chinese Sulfate Cooling Zone (1978-2008)
Regional Cooling = -8.0 W/m2Regional Cooling = -1.0 W/m2
1978 Sulfate Cooling Zone 2008 Sulfate Cooling Zone
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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 PracticeThe 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 PotentialsThe 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 well-established in the peer-reviewed 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, 1505-1525, 2011.
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Global Forcing Potentials by Temperature ThresholdClimate Forcer +1.5°C threshold
(Next 20 years)+2.0°C threshold(Next 35 years)
+4.0°C threshold(Next 100 years)
Carbon dioxideFrom IPCC AR5 1 1 1
Nitrous OxideFrom IPCC AR5 264 280 265
Methane From Shindell 2009 104 73 32
SO2 -> Sulfate aerosols From Collins, 2013 -313 -196 -85
Black carbon (U.S, energy)From Bond 2011 and 2013 2,525 1,608 717
Black carbon (South Asia, biomass)From Bond 2011 and 2013
3,625 2,308 1,030
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Substance GWP-20 GWP-100
Methane (IPCC AR5) 86 34
IPCC has updated the GWP for methane, including one additional effect.
Updating the GWP of Methane
The climate effects of methane are complex:
Absorbs infrared radiation directly
Effects plant growth
On decay, forms ozone and CO2
Forms stratospheric water vapor
Decreases sulfate aerosol cooling
Commonly used GWP value (23) only accounts for one effect over
100 years
Substance GWP-20 GWP-100
Methane (Shindell 2009) 104 32
NASA scientists have assessed estimates including all other effects, resulting in even higher values.
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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0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96100
0
10
20
30
40
50
60
70
80
Years After Manufacture
Forc
ing
10-9
mW
m-2
Refrigerator Climate Footprint Changes over Time
2035 Climate Footprint = 9,900 kilograms
2050 Climate Footprint = 7,900 kilograms
2100 Climate Footprint = 7,700 kilograms
Emissions of short-lived forcers during manufacture
Emissions of CO2 from use accumulate over 14 years
Long-lived gases remain in atmosphere for 100+ years
China is one of the world’s largest emitters of black carbon!
Coal power plant in Inner Mongolia
100+ years
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Changes in Climate Footprint Based on Manufacturing Location
2035 Climate Footprint(kg CO2e)
RefrigeratorMade in China
Manufacturing 5,700
Use(US-14 years) 4,200
Total 9,900
RefrigeratorMade in USA
800
4,200
4,900
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5M tons
1M tons
LCA Scope (per 1,000,000
units)
RefrigeratorMade in
China(tons CO2e)
RefrigeratorMade in USA(tons CO2e)
Manufacturing 5.7 million 0.8 million
Use(US-14 years) 4.2 million 4.2 million
American VS Chinese Manufacturing
(Based on 2035 Climate Footprint)
Potential Impact Reductions
25% efficiency improvement
Switching site of manufacture
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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 [email protected]