1. 1 Time Accounting Sub-Group Update Sub-group members: James Duffy, Keith Kline, Jesper Hedal Kløverpris, Jeremy Martin, Steffen Mueller, Michael O’Hare Outside Expert: Elizabeth Marshall, USDA ERS Agenda 15 min - Review of Fuel Warming Potential – Jeremy 15 min - Baseline Time Accounting – Jesper and Steffen 10 min - Simplified “time-shift” accounting – Michael 5 min – Forest transition approach – Keith 10 min - Social Cost of Carbon applied to biofuels – Liz Marshal 10 min - WRI Time Accounting Workshop Summary - Liz Marshall 30 min - Discussion

2. 2 Fuel Warming Potential Biophysical approach to time accounting analogous to Global Warming Potential O’Hare, Plevin, Martin, Jones, Kenall, Hopson Considered by EPA and CARB during rule development for RFS and LCFS in 2008/2009 Published in Environmental Research Letters in 2009 Reviewed by EPA Peer Review panel in 2009 Discussed in EPA and CARB rulemaking documents but just in case you forgot…..

3. 3 Emissions trajectories over time are complex Figure above represents one set of assumptions 30 years production, GTAP+WH for ILUC, 60 g/MJ w/o ILUC Use BTIME to evaluate your own parameter choices

4. 4 BTIME: Choose your own parameters

5. 5 Extra CO 2 in the Atmosphere CO 2 has a long residence time in the atmosphere Annual additions are greater than annual decay Based on GTAP analysis

6. 6 What do we really care about? Ultimately, human suffering and ecosystem damage from climate change, especially irreversible damage caused by global warming Quantitatively compare the extent of warming caused by scenarios with different temporal emissions profiles Analogous to the comparison of different global warming gasses using the Global Warming Potential

7. 7 Global Warming Potential GWP is the ratio of Cumulative Radiative Forcing (CRF)

8. 8 Cummulative Radiative Forcing Based on GTAP analysis Cumulative Radiative Forcing and NPV (arbitrary units)

9. 9 By analogy, Fuel Warming Potential Radiative Forcing Cumulative Radiative Forcing Ratio of biofuels policy case (b) to reference gasoline case (g)

10. 10 Fuel Warming Potential Carbon Intensity relative to gasoline Based on GTAP analysis

11. 11 By extension, Economic Fuel Warming Potential Physical Fuel Warming PotentialEconomic Fuel Warming Potential Making the very rough assumption that economic damage is proportional to radiative forcing with constant ratio over time

12. 12 FWI p and FWI e Based on GTAP analysis Carbon Intensity relative to gasoline

13. 13 Social Cost of Carbon APPENDIX 15A. SOCIAL COST OF CARBON FOR REGULATORY IMPACT ANALYSIS UNDER EXECUTIVE ORDER 12866 Key assumptions are embedded in integrated assessment models (including damage functions) and discount rates decisions $5-$65/ton in 2010 rising to $16-$135 in 2050 The purpose of the “social cost of carbon” (SCC) estimates […] is to […] incorporate the social benefits of reducing carbon dioxide (CO2) emissions into cost- benefit analyses of regulatory actions that have small, or “marginal,” impacts on cumulative global emissions. The SCC is an estimate of the monetized damages associated with an incremental increase in carbon emissions in a given year. It is intended to include (but is not limited to) changes in net agricultural productivity, human health, property damages from increased flood risk, and the value of ecosystem services due to climate change.

14. 14 Summary Fuel Warming Potential aggregates emissions over time into a relative carbon intensity metric based on a biophysical analysis of their impact on global warming Analogous to Global Warming Potential for different GHGs Early emissions are weighed more heavily because of persistence of GHGs in the atmosphere Economic discounting should be applied to damages rather than emissions Discounting damages increases the weight of near term emissions relative to longer term benefits

15. 15 Additional References O’Hare, Plevin, Martin, Jones, Kenall, Hopson, ERL 2009 BTIME – get the paper, play with the speadsheet at http://rael.berkeley.edu/sites/default/files/BTIME/ http://rael.berkeley.edu/sites/default/files/BTIME/ EPA, 2009. Peer Review Report: Methods and Approaches to Account for Lifecycle Greenhouse Gas Emissions from Biofuels Production Over Time Anderson-Teixeira & DeLucia. 2010. Global Change Biology. The Greenhouse Gas Value of Ecosystems Vasseur, Lesage, Emargni, Deschenes, Samson, EST 2010 Considering Time In LCA: Dynamic LCA And Its Application To Global Warming Impact Assessments