Stabilisation of GHG concentrations in the atmosphere

Findings of the IPCC

Bert Metzco-chairman IPCC Working Group III

INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE (IPCC)

Warning

• These are findings from TAR and SRCCS

• AR4 findings may be different

• AR4 approval/ acceptance dates:– January 29- February 1, 2007: WG I– April 2-5, 2007: WG II– April 30- May 3, 2007: WG III

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Article 2 of the UNFCCC

• “… stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system ..”

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Climate change risks and global mean temperature

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source: IPCC TAR Synthesis Report, 2001

Global mean temperature and stabilisation level

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AR4: look for latest assessment of

• climate sensitivity >> relationship between GHG concentrations and global mean temperature

• climate change risks

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To stabilise concentrations in the atmosphere emissions have to go down to very low levels

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19902000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

IPCC SRES A2 Scenario

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1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

IPCC SRES A1B Scenario

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IPCC SRES B1 Scenario

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IPCC SRES A1T Scenario

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IPCC SRES B2 Scenario

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1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

IPCC SRES A1FI Scenario

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The stabilisation challenge depends on the reference scenario and the stabilisation level

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Emission reductions required for different stabilisation levels

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Emission reductions required for different stabilisation levels

Emission reductions by whom?

• All stabilisation studies ( except B1 baseline) assume that industrialised countries reduce their GHG emissions first

• Emissions from all regions diverge from baselines at some point

• B1 baseline: emission reductions through sustainable development policies

SRCCS Figure TS-12

Illustrative example of the global potential contribution of CCSas part of a mitigation portfolio (MiniCAM and MESSAGE results)

Illustrative example of mitigation options contributing to stabilisation

SRCCS, fig TS12

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Costs of stabilisation go up with lower stabilisation levels CO2 only

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Projected mitigation costs are sensitive to the assumed emissions baseline

Costs for some countries/regions/time periods may be (much) higher

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Decision making

• Step-by-step process towards stabilisation• Balancing risks of insufficient or excessive action• Portfolio of implementing mitigation and

adaptation options, policy instruments and further technology development and diffusion

• Equity and efficiency are critical elements of international regimes

• Integrate climate change mitigation and adaptation into sustainable development policies

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AR4: look for latest assessment of

• Multigas stabilisation studies (CO2 and other GHGs)

• Stabilisation studies with more mitigation options• Stabilisation studies for lower stabilisation levels

than in TAR• New estimates of costs of stabilisation (in

relation to costs of inaction) and distribution of costs depending on international regime modes

• Relation between sustainable development and climate change impacts, adaptation and mitigation

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