Creating Integrated Assessment with Tom Wigley

1. Creating Integrated Assessment with Tom Wigley Symposium in Honor of Tom M. L. Wigley NCAR Mesa Lab Main Seminar Room 1850 Table Mesa Drive, Boulder, CO 80305 USA Jae Edmonds June 19, 2009 PNNL-SA-60765

2. Preface • Thanks to Ben Santer for including me in this symposium. • I would have been very sad to have missed this opportunity to honor Tom. • I could have been in Venice at a great meeting, but I’d MUCH rather be here. • Thanks to Tom for being a great scientist and wonderful colleague, and for giving us an excuse to get together. • I really like the idea of a symposium to honor one of our favorite colleagues, especially a colleague that shows such promise. 2

3. E R W Background • I think I met Tom for the first time at a carbon cycle meeting in 1993 in Snowmass, CO. WRE returned to the Snowmass scene in 2004 • And, while I have maintained a collaborating relationship with Tom for more than a decade, I am a co-author on only about half a dozen papers with Tom. • But, one of those papers has generated more citations than anything else that I have ever written. • I’m referring to WRE: • Wigley, T.M.L., Richels, R. and Edmonds, J.A., 1996: Economic and environmental choices in the stabilization of atmospheric CO2 concentrations. Nature379, 240–243. 3

4. “Where” and “WHEN” flexibility • When the WRE paper was written the idea that cost of emissions mitigation could be reduced by undertaking emissions mitigation wherever they were least expensive was well established. In other words, emissions trading. This was called “Where” flexibility. • If marginal costs are different, then costs can be lowered if the high-cost mitigator mitigates less, and pays the low-cost mitigator to do more. • But applying this principle to time was a completely new concept. • The key insight here is that CO2 is a stock pollutant problem. • It is the concentration, NOT annual emission, that matters. • Climate change depends on CO2 concentration, not annual emissions. 4

5. WRE was a paper about using time to lower the cost of getting to any environmental target. It said that there’s a lowest cost way to limit CO2 concentrations to any level. It challenged an arbitrary set of calculations by the carbon cycle community that had been published in the IPCC AR2 At the time it was extremely controversial. Many people who talk about it have never read the paper, and that was especially true in 1996. WRE was a Rorschach test. Many thought it said that delay in getting started in emissions mitigation was good. There’s nothing like being misunderstood. WRE—Tom the economist 5

6. Not-to-exceed • WRE is a “Not-to-exceed” (NTE) formulation of a CO2 limit. • NTE formulations are interesting constructions • In an NTE scenario emissions are reduced—relative to a reference scenario—until they reach the prescribed upper limit. • Then, society commits to defend that concentration by delivering whatever emissions are necessary to just maintain that level. • The economics of NTE scenarios • While the observed concentration lies below the NTE level, the price rises at the rate of interest plus the rate of removal by the oceans—the Hotelling-Peck-Wan price path. • At the point in time when the concentration exactly equals the NTE level, the system switches over and prices are set by the carbon cycle—that is, allowable emissions are exactly equal to the removal by oceans. 6

7. NTE scenarios Anthropogenic Carbon Emissions WRE trajectories began in 1990 gradually slowed emissions growth before peaking and beginning long term absolute declines. Unfortunately, 1990 is almost two decades ago and optimal trajectories no longer have those two decades with which to work. $102/tC $19/tC $10/tC $4/tC 7

8. The Challenge of Scale—near term CO2 Storage—550 ppm Stabilization Case 8

9. In the mid- and long-term the challenge grows CO2 Storage—550 ppm Stabilization Case 9

10. MAGICC • The WRE scenarios used the Model for the Assessment of Greenhouse-Gas Induced Climate Change (MAGICC). • MAGICC is one of the great contributions to integrated assessment. • It has allowed those of us whose expertise is in the sources of greenhouse gas emissions to deliver results that are consistent with the present best understanding of the carbon cycle and climate science communities. • MAGICC is the work horse of the IA community. • Our integrated assessment model, MiniCAM—a model that is as mini as it can be with 200,000 lines of code—uses MAGICC as its representation of GHG concentrations and climate change. • Tom could be a co-author on every paper I write. 10

11. Overshoot Three EMF22 Scenarios Limiting Radiative Forcing to 2.6 W/m2 (450 ppm CO2-e) • The economics of overshoot—its simpler • Overshoot scenarios consist of two parts • A goal, e.g. atmospheric CO2 concentration, and • A date when that goal is reached. • Cost minimization requires that the price of carbon rise at the rate of interest plus the rate of removal by oceans until the final state—the Hotelling-Peck-Wan price path. • Overshoots have become very popular. • RCP 2.6, the new “low” scenario developed by the IAM community is a classic “overshoot” scenario. Source: Calvin, K., Edmonds, J., Bond-Lamberty, B., Clarke, L., Kyle, P., Smith, S.J., Thomson, A., Wise, M., “2.6: Limiting climate change to 450 ppm CO2 equivalent in the 21st century,” Energy Economics (2009), doi: 10.1016/j.eneco.2009.06.006 11

12. Why are we interested in bioenergy with CCS? Source: Rao, Shilpa, Keywan Riahi and Cheolhung Cho, Detlef van Vuuren, Elke Stehfest, Michel den Elzen, Jasper van Vliet and Morna Isaac. 2008. IMAGE and MESSAGE Scenarios Limiting GHG Concentrations to Low Levels. Framework Contract ENV.C5/FRA/2006/0071. International Institute for Applied Systems Analysis, Laxenburg, Austria. • Overshoots could be developed as a response to learning. • WRE 2006 consider exactly such scenarios • But, overshoot scenarios have been developed in which the overshoot is a fundamental part of the scenario design. • RCP 2.6 12

13. Overshoot • NTE scenarios are conceptually odd, • But, overshoot scenarios are troubling. • Overshoot scenarios may be the only way to reach very low targets. • Overshoots rely on rapid emissions reductions in the 2nd half of the 21st century. • Planning for deep reductions a half century or more in the future is problematic • Overshoot scenarios may include high rates of climate change in the “peaking” phase, and • Commit the world to greater sea level rise. Source: Wigley, T.M.L., Richels, R. and Edmonds, J.A., 2007: Overshoot pathways to CO2 stabilization in a multi-gas context. (In) Human Induced Climate Change: An Interdisciplinary Assessment (eds. Michael Schlesinger, Haroon Kheshgi, Joel Smith, Francisco de la Chesnaye, John M. Reilly, Tom Wilson and Charles Kolstad), Cambridge University Press, 84–92. 13

14. My most recent paper in Science uses MAGICC combined with the MiniCAM terrestrial model • MAGICC provides our description of oceans and climate. • MiniCAM provides our description of economic, energy, land use, and terrestrial carbon cycle. • The scenarios themselves include negative global emissions late in the century and are “overshoot” scenarios. • They focus on the importance of terrestrial carbon in climate stabilization. 14

15. Carbon Pricing in for Two Contrasting Scenarios • Immediate, universal participation by all regions to limit CO2 concentrations in 2095. • Two alternative carbon pricing regimes • Fossil fuel and industrial carbon tax (FFICT)—in this regime only fossil fuel and industrial carbon emissions are valued. Bioenergy is treated as having no net carbon. Terrestrial carbon is valued at zero. • Universal carbon tax (UCT)—in this regime all carbon is valued equally regardless of either its origins or the activity that introduces it to (or removes it from) the atmosphere. 15

16. Carbon Prices: FFICT and UCT 16

17. Net Land Use Change Emissions & Fossil Fuel and Industrial CO2 Emissions • For a given CO2 concentration limit • In the UTC regime ILUC disappears as an issue. • In the FFICT regime high carbon prices drive bioenergy demands and ILUC 17

18. Land use: 450 ppm atmospheric CO2 450 ppm Stabilization Scenario When ALL Carbon is Valued (UCT) Reference Scenario 450 ppm Stabilization Scenario When Terrestrial Carbon is NOT Valued (FFICT) 18

19. When I started working with Tom Integrated Assessment Models The Economy Impacts, Adaptation & Vulnerability Energy Climate Models Health Energy Carbon cycle Agriculture & Forestry Atmospheric Climate Processes Sea Level Rise Ecosystems Oceans Human Settlement & Infrastructure Water 19

20. A “Parallel Approach” Implies Much More Interaction Between the IAM and CMC 20

21. The climate problem has shown absolutely no respect for traditional academic disciplinary categories. • Tom has pushed us all to do a better job of addressing the climate problem. 21

22. Much of Tom’s work has been to bring together the many disparate elements of climate science Integrated Assessment Models Energy The Economy Health Agriculture & Forestry Atmospheric Processes Human Settlement & Infrastructure Water Terrestrial carbon cycle Impacts, Adaptation & Vulnerability Ecosystems Climate Models Oceans Sea Level Rise Cryosphere 22

23. Thanks to Tom • For your science, • For your leadership, and • For being a great colleague! 23

24. END 24

25. Near-term Implications for U.S. Emissions Mitigation of 450 ppm Stabilization U.S. Carbon Emissions 450 ppm (Not-to-Exceed) • U.S. mitigation to achieve 450 ppm CO2 stabilization (“not-to-exceed”) depends on what other countries do. • Our Climate Policy paper keyed non-Annex I emissions mitigation to China. • Immediate accession of all regions means that 50% emissions mitigation in 2050 is more than adequate. • China enters the mitigation coalition in 2020, then US mitigation needs to be complete by 2050 • If China enters the mitigation coalition in 2035, then US mitigation needs to be complete by 2035 25

26. Near-term Implications for CHINA Emissions Mitigation of 450 ppm Stabilization China Carbon Emissions 450 ppm (Not-to-Exceed) • Chinese mitigation to achieve 450 ppm CO2 stabilization (“not-to-exceed”) depends on what other countries do. • Our Climate Policy paper keyed non-Annex I emissions mitigation to China. • Immediate accession of all regions means emissions mitigation of 40% in 2050. • If China enters the mitigation coalition in 2020, then it needs to roughly get on a track for 80% reductions from 2020 emissions by 2065 • If China enters the mitigation coalition in 2035, then mitigation needs to be dramatic. 26

27. Near-term Implications for INDIA Emissions Mitigation of 450 ppm Stabilization India Carbon Emissions 450 ppm (Not-to-Exceed) • Indian mitigation to achieve 450 ppm CO2 stabilization (“not-to-exceed”) depends on what other countries do. • Our Climate Policy paper keyed non-Annex I emissions mitigation to China. • Immediate accession of all regions means that 50% emissions mitigation in 2050 is more than adequate. • China enters the mitigation coalition in 2020, then India enters in 2035 (by assumption). • India entering in 2035 means that it needs to get on track toward an 80% reduction from 2035 emissions by 2080. 27

28. MiniCAM is used to explore the influence of technology availability in emissions mitigation. Global Primary Energy 2095 REF 450 STABILIZATION TODAY 28

29. MiniCAM is used to explore the influence of technology availability in emissions mitigation. Global Primary Energy 2080 REF 450 STABILIZATION TODAY 29

30. MiniCAM is used to explore the influence of technology availability in emissions mitigation. Global Primary Energy 2065 REF 450 STABILIZATION TODAY 30

31. MiniCAM is used to explore the influence of technology availability in emissions mitigation. Global Primary Energy 2050 REF 450 STABILIZATION TODAY 31

32. MiniCAM is used to explore the influence of technology availability in emissions mitigation. Global Primary Energy 2035 REF 450 STABILIZATION TODAY 32

33. MiniCAM is used to explore the influence of technology availability in emissions mitigation. Global Primary Energy 2020 REF 450 STABILIZATION TODAY 33

34. Who is doing the heavy lifting in low stabilization scenarios? Immediate participation Delay participation EMF22 450 ppm CO2-e Limit • Group 3=Rest of World. • Group 2=Brazil, Russian Fed., China, India. • Group 1=Annex I ex. Russian Fed. Overshoot X Not to exceed 34

35. Reference Bioenergy Use: FFICT and UCT 500 ppm Scenarios • SUBSTANTIALLY LESS BIOENERGY PRODUCTION OCCURS THAN WHEN TERRESTRIAL CARBON IS NOT VALUED. • Most bioenergy stillgoes to electricity production with CCSin the concentration limit scenarios. FFICT 500 ppm UCT 500 ppm 35

36. Corn Price When Carbon Is Valued But No Bioenergy Is Produced • Significant crop price escalation occurs if carbon is valued, even in the absence of purpose grown bioenergy production. • Prior to 2040 the influence of bioenergy is negligible. • Prior to 2040 crop price escalation, relative to the reference scenario, is predominantly driven by the value of carbon. 36

37. WRE gradually moved from being controversial to being conventional wisdom Unfortunately, the optimal trajectories that said that beginning in 1990 the world could gradually slow emissions growth before beginning long term reductions in global emissions has been passed—at least for the 450 ppm (atmospheric CO2) not-to-exceed (NTE) scenario. 37