Status and possible solutions to the climate change challenge: What's new since IPCC AR4?

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Status and possible solutions to the climate
change challenge What's new since IPCC AR4?
UNEP
WMO
R K Pachauri Chairman, IPCC Director-General,
TERI The Ny-Ålesund Symposium 8th June 2009
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The IPCC Fourth Assessment Report (2007)

• 2500 scientific expert reviewers
• 800 contributing authors
• 450 lead authors
• 130 countries

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• Warming of the climate system is unequivocal
• - IPCC Fourth Assessment Report

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Observed changes
Global average temperature
Global average sea level
Northern hemisphere snow cover
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• Average arctic temperatures increased at almost
  twice the global average rate in the past 100
  years
• - Annual average arctic sea ice extent has shrunk
  by 2.7 per decade

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• The frequency of heavy precipitation events has
  increased over most land areas
• Rainfall in Mumbai (India), 2005
• 1 million people lost their homes

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• The proportion of tropical cyclones reaching
  higher intensity have increased over the past 3
  decades
• - Cyclone Nargis in Myanmar, 2008
• 100 000 estimated deaths

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Heat waves have become more frequent over most
land areas - Heat wave in Europe, 2003 35 000
deaths
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Continued GHG emissions ... would induce many
changes in the global climate system during the
21st century that would very likely be larger
than those observed during the 20th century -
IPCC Fourth Assessment Report
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Carbon dioxide emissions
Global atmospheric concentrations of greenhouse
gases increased markedly as a result of human
activities, with an increase of 70 in 1970-2004
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Ranges for predicted surface warming
Continued emissions would lead to further warming
of 1.1ºC to 6.4ºC over the 21st century (best
estimates 1.8ºC - 4ºC)
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Examples of impacts associated with global
average temperature change relative to 1980-1999
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Regions likely to be especially affected
The Arctic, because of the impacts of high rates
of warming on natural systems and human
communities
Africa, because of low adaptive capacity and
projected climate change impacts
Small islands, which are highly vulnerable to
projected sea level rise
Asian and African megadeltas, due to large
populations and high exposure to sea level rise,
storm surges and river flooding
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Negative impacts on Europe
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In the course of the century, water supplies
stored in glaciers and snow cover are projected
to decline - The Chacaltaya glacier, 5,300m up
in the Andes, which used to be the world's
highest ski run, has been reduced to just a few
small pieces of ice
2009
1996
Credit Edson Ramirez
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Climate change could lead to some abrupt or
irreversible impacts
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• Delayed emission reductions significantly
  constrain the opportunities to achieve lower
  stabilisation levels and increase the risk of
  more severe climate change impacts
• - IPCC Fourth Assessment Report

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Climate system inertia even if GHG
concentrations were held constant at year 2000
levels, a further warming trend would occur in
the next two decades at a rate of about 0.1C per
decade

• Energy system inertia delayed emission
  reductions lead to investments that lock in more
  emission intensive infrastructure and development
  pathways

Mitigation actions need to start in the short
term in order to have medium- and longer-term
benefits
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Stabilisation scenarios
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Costs of mitigation in 2030
Stabilisation levels (ppm CO2-eq) Range of GDP reduction () Reduction of average annual GDP growth rates (percentage pts)
445 - 535 lt 3 lt 0.12
535 - 590 0.2 2.5 lt 0.1
590 - 710 -0.6 1.2 lt 0.06
Mitigation measures would induce 0.6 gain to 3
decrease of GDP in 2030
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• There is substantial potential for the
  mitigation of global GHG emissions over the
  coming decades that could reduce emissions
  below current levels
• - IPCC Fourth Assessment Report

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All stabilisation levels assessed can be
achieved by deployment of a portfolio of
technologies that are currently available or
expected to be commercialised in coming decades
This assumes appropriate and effective incentives
are in place for their development, acquisition,
deployment and diffusion
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Key technologies currently available
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Technologies expected to be commercialised before
2030
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Key mitigation instruments, policies practices
Research, development and demonstration
Appropriate energy infrastructure investments
Regulations and standards
Taxes and charges
Change in lifestyles consumption patterns
Effective carbon-price signal
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Beyond the IPCC Fourth Assessment Report
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Evolution of the climate science

• Deeper understanding and quantification of the
  processes governing the climate system have
  progressed rapidly since the IPCC First
  Assessment Report (1990)
• The main scientific conclusions from the sequence
  
• of IPCC assessments have been refined but not
  significantly redirected
• Recently observed climate changes remain coherent
  with the AR4 conclusions, although longer-term
  observation is required to draw significant
  conclusions on climate evolutions

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Research-related priorities

• Impacts under different assumptions about future
  development pathways
• Damages avoided by different levels of emissions
  reduction
• Expected impacts at the regional and local level
• Causes and thresholds of possible abrupt climate
  changes
• Links between climate change and other policies
• Costs of impacts of, and responses to, climate
  change

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Coming IPCC reports

• 5th Assessment Report (to be finalised in 2014)
• Revised set of scenarios based on possible
  evolutions of GHG emission trajectories
• Deeper coverage of the socio-economic and
  humanitarian dimensions of climate change

• Special Reports
• Renewable energy 2010
• Extreme events and disasters 2011

• Technical Papers

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Democracy must in essence therefore, mean the art
and science of mobilizing the entire physical,
economics and spiritual resources of all the
various sections of the people in the service of
the common good for all.