1. Keeping warming below 2°C: link and consistency between INDC assessments and long-term goals Joeri Rogelj Side Event COP21 - Paris 1 December 2015

2. Science facts recap

3. IPCC AR5 WGI

4. Science facts recap Any global temperature target 1.5°C 2°C 3.25°C ? See: Knutti & Rogelj, Climatic Change, 2015

5. Science facts recap Any global temperature target Limited amount of carbon emissions 1.5°C 2°C 3.25°C ? carbon budget See: Knutti & Rogelj, Climatic Change, 2015

6. Science facts recap Any global temperature target Limited amount of carbon emissions Net zero global carbon emissions = geophysical requirement for any temperature stabilization level 1.5°C 2°C 3.25°C ? carbon budget See: Knutti & Rogelj, Climatic Change, 2015

7. Science facts recap Higher near-term emissions: steeper and deeper long-term reductions 1.5°C 2°C 3.25°C ? carbon budget

8. Science facts recap Higher near-term emissions: steeper and deeper long-term reductions 1.5°C 2°C 3.25°C ? carbon budget

9. Science facts recap Higher near-term emissions: steeper and deeper long-term reductions 1.5°C 2°C 3.25°C ? carbon budget

10. Science facts recap Higher near-term emissions: steeper and deeper long-term reductions If budget is exceeded: CO 2 removal requirement 1.5°C 2°C 3.25°C ? carbon budget

11. Operationalization of these facts? Consistent sets near and long-term goals Depend on policy choices: –Time of peak –Height of peak –Near-term evolution of global emissions (next 10-20 years) –Portfolio of technologies –… 1.5° C 2°C 3.25°C ? carbon budget

12. Question What do current assessments for near-term emissions imply for global long-term targets?

13. Some definitions Global net zero CO 2 emissions = Zero CO 2 emissions at a global scale = Carbon neutrality Global net zero CO 2 emissions of energy and industrial processes = Zero CO 2 emissions of energy and industrial processes at a global scale = Full decarbonisation Global net zero Kyoto-GHG emissions = Zero Kyoto-GHG emissions at a global scale = (NOT?) Climate neutrality

14. A quantitative look Influence of timing of the peak

15. A quantitative look Influence of timing of the peak Rogelj et al. Environ. Research Letters 2015 Scenarios from IPCC AR5

16. A quantitative look Influence of timing of the peak Rogelj et al. Environ. Research Letters 2015 Scenarios from IPCC AR5 -peaking around 2010

17. A quantitative look Influence of timing of the peak Rogelj et al. Environ. Research Letters 2015 Scenarios from IPCC AR5 -peaking around 2010 -peaking around 2020

18. A quantitative look Influence of timing of the peak Rogelj et al. Environ. Research Letters 2015 Scenarios from IPCC AR5 -peaking around 2010 -peaking around 2020 -peaking around 2030

19. A quantitative look Influence of timing of the peak Rogelj et al. Environ. Research Letters 2015 Scenarios from IPCC AR5 -peaking around 2010 -peaking around 2020 -peaking around 2030 Conclusion: Later peaking drives earlier net zero global CO 2 emissions

20. A quantitative look Influence of height of the peak Rogelj et al. Environ. Research Letters 2015 For a given CO 2 budget

21. A quantitative look Influence of height of the peak Rogelj et al. Environ. Research Letters 2015 For a given CO 2 budget -Higher 2020 and 2030 emissions -Earlier global net zero CO 2 emissions

22. Implications for 1.5 and 2°C and a long-term zero emissions goal Rogelj et al. Environ. Research Letters 2015

23. Implications for 1.5 and 2°C and a long-term zero emissions goal Rogelj et al. Environ. Research Letters 2015

24. What do INDCs tell us? UNFCCC Synthesis report on the aggregate effect of the intended nationally determined contributions UNEP 2015 UNEP Emissions Gap Report A UNEP Synthesis Report

25. Differences between assessments UNFCCCUNEP GAP Assessment type Single elaborated INDC estimate Assessment of other published studies Countries covered 119Varies with underlying studies Uncertainty Structured exploration with statistical methods Variation between studies Treatment of conditionality Part of structured uncertainty analysis Defined by contributing modelling groups Treatment of non-covered countries Use regional projections of Cancun pledges. Part of structured uncertainty analysis Defined by contributing modelling groups 2030 estimate (SAR GWP) 55 (52-57) GtCO 2 -eq/yr54-56 (52-59) GtCO 2 -eq/yr

26. Differences between assessments UNFCCCUNEP GAP Assessment type Single elaborated INDC estimate Assessment of other published studies 2030 estimate (SAR GWP) 55 (52-57) GtCO 2 -eq/yr54-56 (52-59) GtCO 2 -eq/yr 2°C pathways comparison IPCC database Starting in 2010 or 2020 >66% during 21 century IPCC database Starting mitigation in 2020 >66% in 2100

27. What do INDCs tell us for the timing of zero global CO 2 emissions Rogelj et al. Environ. Research Letters 2015 50-66% 2°C in 2100

28. What do INDCs tell us for the timing of zero global CO 2 emissions Rogelj et al. Environ. Research Letters 2015 50-66% 2°C in 2100

29. What do INDCs tell us for the timing of zero global CO 2 emissions Rogelj et al. Environ. Research Letters 2015 50-66% 2°C in 2100

30. Is this a sufficient condition? Rogelj et al. Environ. Research Letters 2015

31. Outlook Why a clearly defined goal matters –Sense of global direction –Warranting science-based policy –Environmental integrity