Stabilisation of GHG concentrations
in the atmosphere
Findings of the IPCC
Bert Metz
co-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
IPCC
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 ..”
IPCC
Climate change risks and global mean
temperature
IPCC
Global mean temperature and stabilisation level
source: IPCC TAR Synthesis Report, 2001
IPCC
AR4: look for latest assessment of
• climate sensitivity >> relationship between
GHG concentrations and global mean
temperature
• climate change risks
IPCC
To stabilise concentrations in the atmosphere
emissions have to go down to very low levels
IPCC
IPCC
The stabilisation challenge depends on the
reference scenario and the stabilisation level
Global Anthropogenic Carboon Dioxide Emissions (GtC)
40
35
40
IPCC SRES A1B Scenario
35
30
30
25
25
20
20
ref
15
10
650
550
450
5
0
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
35
IPCC SRES A2 Scenario
20
15
10
ref
650
550
450
5
0
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
10
750
650
550
450
5
0
1990
2000
2010
2020
2030
2040
2050
2060
2070
2080
2090
2100
40
IPCC SRES B1 Scenario
35
30
30
25
25
25
20
20
20
15
15
15
30
ref
25
15
35
IPCC SRES A1FI Scenario
30
40
40
35
40
IPCC SRES A1T Scenario
IPCC SRES B2 Scenario
ref
ref
750
10
10
550
5
IPCC
5
550
650
550
450
5
450
0
0
19902000
10
ref
2010 2020 2030 2040 2050 2060 2070 2080 2090
2100
19902000
0
2010 2020 2030 2040 2050 2060 2070 2080 2090
2100
19902000
2010
2020
2030
2040
2050
2060
2070
2080
2090
2100
Emission reductions required for different
stabilisation levels
IPCC
IPCC
Emission reductions required for different
stabilisation levels
IPCC
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
Illustrative
example
of
mitigation
options
ustrative example of the global potential contribution of CCS
contributing
to stabilisation
part of a mitigation
portfolio (MiniCAM
and MESSAGE results)
SRCCS, fig TS12
IPCC
IPCC
Costs of stabilisation go up with lower stabilisation levels
CO2 only
IPCC
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
IPCC
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
IPCC