310 likes | 322 Views
This side event at COP21 in Paris explores the science facts and assessments related to the global temperature targets and carbon emissions budgets to keep warming below 2°C. It discusses the importance of consistent sets of near and long-term goals, the influence of timing and height of peak emissions, and the implications for achieving a long-term zero emissions goal. The event also evaluates the current INDC assessments and their implications for global long-term targets.
E N D
Keeping warming below 2°C:link and consistency between INDC assessments and long-term goals Joeri RogeljSide Event COP21 - Paris1 December 2015
Science facts recap IPCC AR5 WGI
Science facts recap 1.5°C • Any global temperature target 2°C 3.25°C? See: Knutti & Rogelj, Climatic Change, 2015
Science facts recap 1.5°C • Any global temperature target • Limited amount of carbon emissions 2°C 3.25°C? carbon budget See: Knutti & Rogelj, Climatic Change, 2015
Science facts recap 1.5°C • Any global temperature target • Limited amount of carbon emissions • Net zero global carbon emissions= geophysical requirementfor any temperature stabilization level 2°C 3.25°C? carbon budget See: Knutti & Rogelj, Climatic Change, 2015
Science facts recap carbonbudget 1.5°C • Higher near-term emissions:steeper and deeper long-term reductions 2°C 3.25°C?
Science facts recap carbonbudget 1.5°C • Higher near-term emissions:steeper and deeper long-term reductions 2°C 3.25°C?
Science facts recap carbonbudget 1.5°C • Higher near-term emissions:steeper and deeper long-term reductions 2°C 3.25°C?
Science facts recap carbonbudget 1.5°C • Higher near-term emissions:steeper and deeper long-term reductions • If budget is exceeded: CO2 removal requirement 2°C 3.25°C?
Operationalization of these facts? carbonbudget 1.5°C • 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 • … 2°C 3.25°C?
Question What do current assessments for near-term emissionsimply for global long-term targets?
Some definitions Global net zero CO2 emissions = Zero CO2 emissions at a global scale = Carbon neutrality Global net zero CO2 emissions of energy and industrial processes = Zero CO2 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
A quantitative look Influence of timing of the peak
A quantitative look Influence of timing of the peak Scenarios from IPCC AR5 Rogelj et al. Environ. Research Letters 2015
A quantitative look Influence of timing of the peak Scenarios from IPCC AR5 • peaking around 2010 Rogelj et al. Environ. Research Letters 2015
A quantitative look Influence of timing of the peak Scenarios from IPCC AR5 • peaking around 2010 • peaking around 2020 Rogelj et al. Environ. Research Letters 2015
A quantitative look Influence of timing of the peak Scenarios from IPCC AR5 • peaking around 2010 • peaking around 2020 • peaking around 2030 Rogelj et al. Environ. Research Letters 2015
A quantitative look Influence of timing of the peak Scenarios from IPCC AR5 • peaking around 2010 • peaking around 2020 • peaking around 2030 Conclusion: Later peaking drives earliernet zero global CO2 emissions Rogelj et al. Environ. Research Letters 2015
A quantitative look Influence of height of the peak For a given CO2 budget Rogelj et al. Environ. Research Letters 2015
A quantitative look Influence of height of the peak For a given CO2 budget • Higher 2020 and 2030 emissions • Earlier global net zero CO2 emissions Rogelj et al. Environ. Research Letters 2015
Implications for 1.5 and 2°Cand a long-term zero emissions goal Rogelj et al. Environ. Research Letters 2015
Implications for 1.5 and 2°Cand a long-term zero emissions goal Rogelj et al. Environ. Research Letters 2015
What do INDCs tell us? UNFCCC Synthesis report on the aggregate effect of the intended nationally determined contributions UNEP2015 UNEP Emissions Gap ReportA UNEP Synthesis Report
What do INDCs tell us for the timingof zero global CO2 emissions 50-66% 2°C in 2100 Rogelj et al. Environ. Research Letters 2015
What do INDCs tell us for the timingof zero global CO2 emissions 50-66% 2°C in 2100 Rogelj et al. Environ. Research Letters 2015
What do INDCs tell us for the timingof zero global CO2 emissions 50-66% 2°C in 2100 Rogelj et al. Environ. Research Letters 2015
Is this a sufficient condition? Rogelj et al. Environ. Research Letters 2015
OutlookWhy a clearly defined goal matters • Sense of global direction • Warranting science-based policy • Environmental integrity