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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. Introduction.
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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
Introduction • Part 1: Why 2°C ? What CO2 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?
Part 1:Why 2°C? What equilibrium CO2-equivalent level corresponds with 2oC?
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.[...]”(1939th 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)
Expected warming for ~550ppm CO2eq Climate Sensitivity ... ... summarizes key uncertainties in climate science ... is the expected average warming of the earth’s surface for a doubling of CO2 concentrations (about 550 ppm CO2)
Background: Difference between CO2 and CO2equivalence • “CO2equivalence” summarizes the climate effect (‘radiative forcing’) of all human-induced greenhouse-gases and aerosols, as if we only changed the atmospheric concentrations of CO2. • Like “bread exchange” units for food or “tonnes oil equivalent (toe)” for energy sources.
Expected warming for ~550ppm CO2eq • New research cannot exclude very high warming levels (e.g. > 4.5°C) for stabilization of greenhouse gases at 550ppm CO2–eq. • “The fact that we are uncertain may actually be a reason to act sooner rather than later” (Eileen Claussen)
Conclusions Part 1 • 550 ppm CO2 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 CO2eq (risk to overshoot 2°C is about 25%). • Dependent on climate sensitivity PDF
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 CO2eq • Climate calculations by simple climate model
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: • Current studies show more abatements are possible • More optimistic, simple assumptions for the MACs (e.g. energy CO2 MACs now additional improvement of 0.2%/year)
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 CO2-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;
Cost-optimal reduction over GHGs • Main focus on energy-related CO2 reductions • In short terms, potentially large incentives for sinks and non-CO2 GHGs (cheap options)
Conclusions Part 2 • 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 CO2 emissions
Part 3:What are the (regional) emission reduction implications?
Change of global GHG emissions (incl. LUCF CO2 emissions) compared to 1990 level (in %) • 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 (excl. LUCF CO2 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).
Change emissions compared to 1990 level in 2020 excl. LUCF CO2 for Multi-Stage regime (%)
Change emissions compared to 1990 level in 2050 excl. LUCF CO2 for Multi-Stage regime (%)
Conclusions Part 3 (Global) • Overall global emissions (Kyoto gas emissions + landuse CO2): • 400ppm CO2eq: 50% to 60% below 1990 by 2050 • 450ppm CO2eq: 30% to 40% below 1990 by 2050 • Assuming landuse CO2 emission decrease as specified, needed global Kyoto gas emissions reductions are less: • 400ppm CO2eq: 35% to 45% below 1990 by 2050 • 450ppm CO2eq: 15% to 25% below 1990 by 2050
Conclusions Part 3 (Regional) • 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 4 • 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)
Overall conclusions • Multi-gas mitigation pathways • 550 ppm CO2 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 CO2 emissions) in 2050 compared to 1990 levels (450/400ppm CO2eq).
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
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
Thank you! • Contact: • michel.den.elzen@rivm.nl • malte.meinshausen@ethz.ch • Presentation will be made available from • www.rivm.nl/ieweb/ • www.simcap.org