Global longterm strategies for stabilizing greenhouse gas concentrations

1
Global long-term strategies for stabilizing
greenhouse gas concentrations

• Nebosja NakicenovicKeywan Riahi, Shilpa Rao

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Approach

• IIASAs MESSAGE energy model extended to other
  GHG emitting sectors (agriculture and forestry
  including C sinks)
• Multi-gas (CO2, CH4, N2O, HFC, CF4, SF6) black
  carbon
• Bottom-up representation of mitigation
  technologies
• Endogenized competition of mitigation options
  across all sectors
• Endogenized energy feedback effects from non-CO2
  mitigation (capture of CH4 in coal mines, CH4
  from landfills, etc.)
• Global, 11 world regions, up to 2100
• Output Costs, main mitigation measures,
  uncertainties

3
The fossil fuel intensive path A2SRES
assumptions

• High population (12 bn)
• Low per-capita income
• Fossil fuel intensive development
• Fragmented world
• Emphasis on regional cultures, traditions,
  cooperation and economic development unions
• Little technology transfer to developing
  countries
• Large regional disparities
• Ratio of North-South income gap 41 in PPP (as
  today)
• Very little further convergence

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The sustainable development path B1SRES
assumptions

• Rapid global economic development, high
  per-capita income
• Fast economic "catch-up" of developing countries
  North-South income gap reduced to less than
  21 (PPP)
• Rapid structural change of the global economy
• Dematerialization" of the economies
• Reduced energy intensity
• Changed life styles
• Invoked by increased environmental awareness

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Global GHG emission paths SRES A2 and B1no
climate measures scenarios Gt C/yr
A2 Fossil fuel intensive
B1 Sustainabledevelopment
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The sustainable development path B1Assumed
non-climate policies (according to SRES)

• Globalization with enhanced multi-lateral
  cooperation
• Technology transfer with fast introduction of
  advanced technologies also in developing
  countries
• Successful large-scale RD programs
• Targeted population policies to reduce fertility
  rates in developing countries
• World population 6 billion
• Other sustainable development policies
• Aggressive air pollution control
• Stringent efficiency standards

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Illustrative stabilization analysisfor the A2
and B1 paths

• Illustrative GHG stabilization target
• 4.5 W/m2 radiative forcing (2.3 degrees C)
  increase in 2100 compared to pre-industrial
  levels
• To be achieved through control of all 6 Kyoto
  gases
• Provisional analysis uses 100 years GWPs

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Global GHG emission pathsA2 and B1 stabilization
cases Gt C/yr
A2 Fossil fuel intensive
B1 Sustainabledevelopment
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Main mitigation measuresCumulative carbon
removal, 2000-2100 Gt C
800
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Co-benefits of GHG stabilizationon emissions of
black carbon and organic carbon, A2 scenario Mt
Black carbon
Organic carbon
Emission reductions from stabilization in
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Conclusions

• Sustainable development paths achieve a
  significant share of stabilization effort as a
  co-benefit
• In fossil-intensive paths stabilization efforts
  are very costly
• Non-CO2 mitigation options reduce stabilization
  costs
• Mitigation of non-CO2 gases make an important
  contribution in the near-term, but CO2
  mitigation remains essential in the long-term
• GHG stabilization paths lead to a significant
  reduction of black and organic carbon as a
  co-benefit