Transcript Air Pollution and Climate - IIASA

Convention on Long-range
Transboundary Air Pollution
Cooperative programme for monitoring
and evaluation of the long-range transmission
of air pollutants in Europe
European Topic Centre
on Air and Climate Change
LINKAGES AND SYNERGIES OF
REGIONAL AND GLOBAL EMISSION
CONTROL
Workshop of the UN/ECE
Task Force on Integrated Assessment Modelling
January 27-29, 2003
International Institute for Applied Systems Analysis
Questions
• What do we know about the linkages between
air pollution and climate change?
• How important are these linkages?
• Which of these linkages could potentially
influence rational policies to control emissions?
Sessions
1. Physical linkages through atmospheric chemistry
2. Physical linkages through environmental impacts
3. Concerns of national decision makers
4. Synergistic measures: Sectoral perspectives
5. Strategies to harness synergies
6. Economic instruments
7. Modelling approaches
Linkages through atmospheric chemistry
• Also air pollutants exert climate impacts
• Radiative forcing (RF) of ozone and PM are
different in space and time from that of GHGs
• Sulphates, nitrates and organic carbon have
cooling effect and can reduce precipitation
• Black carbon has positive forcing
• Ozone has strong positive RF, better understood
than that of aerosols
• Methane influences RF and ozone
• CC impacts on meteorology seem less relevant
for the next two decades
Linkages through environmental impacts
Numerous linkages exist, not all of them are yet
fully understood.
• CC might reduce ecosystems sensitivity to
acidification
• Increased N deposition increases C storage
• Air pollution weakens plant growth, reduces C
storage
• Air pollution and CC affect biodiversity
Synergies of multi-objective strategies
• Simultaneous emission controls result in multiple
benefits.
• Synergies may free resources.
• Existing trade-offs should be considered.
• Global CO2 stabilization will lead to lower SO2
emissions. Extent depends on how reduction is
achieved.
• Synergies in agricultural sector important.
• Significant ancillary benefits demonstrated in
many case studies
Strategic aspects
GHG emission trading schemes can have impacts
on air pollution:
• C trading influences air pollution control costs
• C trading affects regional environmental impacts
of air pollution. Ancillary (dis-)benefits should be
considered.
• Effects of C trading are uncertain. This causes a
problem for defining an air pollution baseline
scenario.
Modelling the linkages
• Modelling requires bridging different temporal
and spatial scales.
• Extension of multi-effect approach? Could offer a
systematic tool for choosing multiple targets of
different types.
• Models will have to address sustainable
development and structural changes beyond
cost-effectiveness.
• Keep models manageable!
The way forward
• Extension of RAINS towards greenhouse gas cost
curves is underway to
– Help decision makers maximizing positive synergies and
minimizing trade-offs, and
– Selecting most cost-effective measures in view of the
objectives of both policy areas.
• Primary focus should be on scientific issues.
• Improved contacts between air pollution and
climate change science communities necessary.