1. RIVM (the Netherlands) and ETH (Switzerland) 1 Emission implications of long-term climate targets - a work-in-progress report - Michel den Elzen (RIVM, the Netherlands) Malte Meinshausen (ETH Zurich, Switzerland) Side Event COP-10 13th December 2004 Buenos Aires

2. RIVM (the Netherlands) and ETH (Switzerland) 2 Introduction  Part 1: Why 2°C ? What CO 2 level corresponds with a 2°C target?  Part 2: The method to derive emission pathways with cost-effective multi-gas mixes of reductions.  Part 3:What are the (regional) emission reduction targets?  Part 4: What is the impact of further delay?

3. RIVM (the Netherlands) and ETH (Switzerland) 3 Part 1: Why 2°C? What equilibrium CO 2 -equivalent level corresponds with 2 o C?

4. RIVM (the Netherlands) and ETH (Switzerland) 4 EU’s 2°C target  “[...] the Council believes that global average temperatures should not exceed 2 degrees above pre-industrial level and that therefore concentration levels lower than 550 ppm CO2 should guide global limitation and reduction efforts. [...]” (1939 th Council meeting, Luxembourg, 25 June 1996)  “ REAFFIRMS that, with a view to meeting the ultimate objective of the United Nations Framework Convention on Climate Change [...] to prevent dangerous anthropogenic interference with the climate system, overall global annual mean surface temperature increase should not exceed 2°C above pre-industrial levels in order to limit high risks, including irreversible impacts of climate change; RECOGNISES that 2°C would already imply significant impacts on ecosystems and water resources [...]” (2610th Council Meeting, Luxembourg, 14 October 2004 Council 2004, 25-26 March 2004)

5. RIVM (the Netherlands) and ETH (Switzerland) 5 Temperature increase higher over land

6. RIVM (the Netherlands) and ETH (Switzerland) 6 Reasons for Concern (IPCC TAR WGII)

7. RIVM (the Netherlands) and ETH (Switzerland) 7 Millions at Risk (Parry et al., 2001)

8. RIVM (the Netherlands) and ETH (Switzerland) 8 Expected warming for ~550ppm CO 2 eq Climate Sensitivity...... summarizes key uncertainties in climate science... is the expected average warming of the earth’s surface for a doubling of CO 2 concentrations (about 550 ppm CO 2 )

9. RIVM (the Netherlands) and ETH (Switzerland) 9 Background: Difference between CO 2 and CO 2 equivalence Conversion Table for > 2100 CO 2 (ppmv) + other GHG + aerosols CO 2 eq (ppmv) 350 + other≈400 390 + other≈450 470 + other≈550 550 + other≈650  “CO 2 equivalence” summarizes the climate effect (‘radiative forcing’) of all human-induced greenhouse- gases and aerosols, as if we only changed the atmospheric concentrations of CO 2.  Like “bread exchange” units for food or “tonnes oil equivalent (toe)” for energy sources.

10. RIVM (the Netherlands) and ETH (Switzerland) 10 Expected warming for ~550ppm CO 2 eq  New research cannot exclude very high warming levels (e.g. > 4.5°C) for stabilization of greenhouse gases at 550ppm CO 2 –eq.  “The fact that we are uncertain may actually be a reason to act sooner rather than later” (Eileen Claussen)

11. RIVM (the Netherlands) and ETH (Switzerland) 11 The risk to overshoot 2°C

12. RIVM (the Netherlands) and ETH (Switzerland) 12 The Risk to overshoot 2°C

13. RIVM (the Netherlands) and ETH (Switzerland) 13 Conclusions Part 1  550 ppm CO 2 equivalence is “unlikely” to meet the 2°C target  The risk to overshoot 2°C can be substantially reduced for lower stabilization levels.  There is about a fifty:fifty chance to meet 2°C by stabilizing at 450ppm  There is a “likely” achievement of the 2°C target for stabilization at 400ppm CO 2 eq (risk to overshoot 2°C is about 25%).  Dependent on climate sensitivity PDF

14. RIVM (the Netherlands) and ETH (Switzerland) 14 Part 2: The method to calculate emission pathways

15. RIVM (the Netherlands) and ETH (Switzerland) 15 Method: FAIR-SiMCaP  FAIR (RIVM)  Calculates the emission allowances and abatement costs of post-2012 regimes  Here we use the cost-model:  cost-optimal mixes of greenhouse gas for total reductions (6 GHGs) every 5 year periods  least costs approach using on MAC curves  Not over time  SiMCaP (ETH Zurich)  calculates parameterised emission pathways to achieve predefined climate targets, like 400ppm CO 2 eq  Climate calculations by simple climate model

16. RIVM (the Netherlands) and ETH (Switzerland) 16 Method: FAIR-SiMCaP

17. RIVM (the Netherlands) and ETH (Switzerland) 17 Basic assumptions  Three baseline scenarios:  IMAGE-B1 (IPCC B1, MACs B1 & LUCF: B1)  CPI (middle IPCC, MACs CPI & LUCF: CPI)  CPI+tech (MACs additional technological improvements) & LUCF: B1)  Rationale behind CPI + tech: 1.Current studies show more abatements are possible 2.More optimistic, simple assumptions for the MACs (e.g. energy CO 2 MACs now additional improvement of 0.2%/year)

18. RIVM (the Netherlands) and ETH (Switzerland) 18 Basic assumptions (continued)  In order to avoid global emission reduction rates exceeding 3%/year, the default scenarios assume early reductions. Peak of global emissions in 2015-2020  Early peaking is technically feasible, costs not too high, but … political willingness?  Focus on CO 2 -equivalent concentration stabilisation levels of 400, 450, 500 and 550 ppm  The lower concentration levels include overshooting:  Stabilisation at 400 ppm: Peaking at 480 ppm;  Stabilisation at 450 ppm: Peaking at 500 ppm;  Stabilisation at 500 ppm: Peaking at 525 ppm;

19. RIVM (the Netherlands) and ETH (Switzerland) 19 Cost-optimal reduction over GHGs  Main focus on energy-related CO 2 reductions  In short terms, potentially large incentives for sinks and non- CO 2 GHGs (cheap options)

20. RIVM (the Netherlands) and ETH (Switzerland) 20 Fossil CO 2 emissions

21. RIVM (the Netherlands) and ETH (Switzerland) 21 Other Greenhouse gas Emissions

22. RIVM (the Netherlands) and ETH (Switzerland) 22 Greenhouse gas Concentrations

23. RIVM (the Netherlands) and ETH (Switzerland) 23 Contribution GHGs to net radiative forcing

24. RIVM (the Netherlands) and ETH (Switzerland) 24  Presented multi-gas scenarios are roughly within the range of existing mitigation scenarios.  The applied method reflects the existing policy-framework and assumes cost-minimizing achievements of targets in each 5 year period:  This results in near-term incentives for non-CO2 reductions and for sinks  But in the long-term the focus has to be on reductions in CO 2 emissions Conclusions Part 2

25. RIVM (the Netherlands) and ETH (Switzerland) 25 Part 3: What are the (regional) emission reduction implications?

26. RIVM (the Netherlands) and ETH (Switzerland) 26 Emission pathways with different baselines

27. RIVM (the Netherlands) and ETH (Switzerland) 27 The default emission pathways

28. RIVM (the Netherlands) and ETH (Switzerland) 28  In 2020, global emissions may increase from 10-25% above 1990 levels (400-450ppm).  In 2050, the emissions have to be reduced by 30-60% Change of global GHG emissions (incl. LUCF CO 2 emissions) compared to 1990 level (in %)

29. RIVM (the Netherlands) and ETH (Switzerland) 29 Change of global GHG emissions (excl. LUCF CO 2 emissions) compared to 1990 level (in %)  If landuse CO2 emissions decrease, then reduction needs for the Kyoto gas emissions only (without landuse CO2) are relaxed by about 10%-15%.  By 2050,  20-45% below 1990 levels (400-450ppm).

30. RIVM (the Netherlands) and ETH (Switzerland) 30 Change emissions compared to 1990 level in 2020 excl. LUCF CO 2 for Multi-Stage regime (%)

31. RIVM (the Netherlands) and ETH (Switzerland) 31 Change emissions compared to 1990 level in 2050 excl. LUCF CO 2 for Multi-Stage regime (%)

32. RIVM (the Netherlands) and ETH (Switzerland) 32  Overall global emissions (Kyoto gas emissions + landuse CO 2 ):  400ppm CO 2 eq: 50% to 60% below 1990 by 2050  450ppm CO 2 eq: 30% to 40% below 1990 by 2050  Assuming landuse CO2 emission decrease as specified, needed global Kyoto gas emissions reductions are less:  400ppm CO 2 eq: 35% to 45% below 1990 by 2050  450ppm CO 2 eq: 15% to 25% below 1990 by 2050 Conclusions Part 3 (Global)

33. RIVM (the Netherlands) and ETH (Switzerland) 33  Focusing on Kyoto gas emissions excluding landuse emissions:  In 2020, Annex I emissions need to be reduced ~ 30% below 1990 levels for 400ppm, and ~15% 450ppm.  The reductions are differentiated amongst the Parties, Annex I takes the lead, followed by the more advance developing countries, and then the low-income countries.  For meeting the lower concentration levels major developing countries have to participate in the reductions between 2015 and 2025 Conclusions Part 3 (Regional)

34. RIVM (the Netherlands) and ETH (Switzerland) 34 Part 4: What is the impact of further delay

35. RIVM (the Netherlands) and ETH (Switzerland) 35 The effect of delay: 450ppm

36. RIVM (the Netherlands) and ETH (Switzerland) 36 The effect of delay: 400ppm

37. RIVM (the Netherlands) and ETH (Switzerland) 37 The effect of delay: 400ppm

38. RIVM (the Netherlands) and ETH (Switzerland) 38  A delay of global action of just five years matters.  Global emissions will have to peak in 10 to 15 years to limit the risk of overshooting 2°C to reasonable levels.  The consequence of delay are:  Lower absolute emissions after around 2040  Steeper maximal reduction rates already from 2020 / 2025  “Delaying action for a decade, or even just years, is not a serious option” (Sir David King, Sience,9 January 2004) Conclusions Part 4

39. RIVM (the Netherlands) and ETH (Switzerland) 39 Overall conclusions

40. RIVM (the Netherlands) and ETH (Switzerland) 40 Overall conclusions  Multi-gas mitigation pathways  550 ppm CO 2 eq. is “unlikely” to meet the 2°C target  Limiting the risk to overshoot 2°C to less then 33% requires stabilization at approximately 400ppm.  It seems necessary, that global emissions peak before 2020 to achieve 400 or 450ppm stabilization levels. Cost of delay potentially very high.  This is followed by reductions in the order of 30% to 60% (incl. land use CO 2 emissions) in 2050 compared to 1990 levels (450/400ppm CO 2 eq).

41. RIVM (the Netherlands) and ETH (Switzerland) 41 Overall conclusions (continued)  Regional emission reductions depend on:  emissions growth in the baseline  allocation scheme for differentiated commitments  abatement potential and reduction costs  In 2020, Annex I emission need to be approximately 30% below 1990 levels for 400ppm, and approximately 20% lower for 450ppm stabilization.  For meeting the lower concentration levels, major developing countries have to participate in the reductions between 2015 and 2025

42. RIVM (the Netherlands) and ETH (Switzerland) 42 Reminder - Disclaimer  The presented work is part of a longer term project.  Cost estimates, in particular non-fossil CO2, will be explored in more detail (implementation barriers).  Cost of delayed pathways will be explored with dynamic energy model TIMER (inertia, technological improvements, forgone learning effects)  Work in progress

43. RIVM (the Netherlands) and ETH (Switzerland) 43 Thank you!  Contact:  michel.den.elzen@rivm.nl  malte.meinshausen@ethz.ch malte.meinshausen@ethz.ch  Presentation will be made available from  www.rivm.nl/ieweb/  www.simcap.org