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Into a warming worldWMO UNEP
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The Intergovernmental panelon climate change:
Science at the service
of policy-making
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1. Experts review the first draft of the report
2. Governments and experts review the seconddraft of the report and the draft Summary forPolicymakers
3. Governments review word-by-word therevised draft Summary for Policymakers
Writing and review process
of the IPCC assessment reports
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+2500 scientific expert reviewers
800 contributing authors
450 lead authors
+130 countries
The IPCC Fourth Assessment Report(2007)
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References to the IPCC Fourth AssessmentReport in the Bali Action Plan (December 2007)
Responding to the findings of the Fourth Assessment Report of theIntergovernmental Panel on Climate Change that warming of theclimate system is unequivocal, and thatdelay in reducing emissionssignificantly constrains opportunities to achieve lower stabilizationlevels and increases the risk of more severe climate change impacts
[] urgent and immediate needs of developing countries that areparticularly vulnerable to the adverse effects of climate change,especially the least developed countries and small island developingStates, and further taking into account the needs of countries in Africaaffected by drought, desertification and floods
[] emphasizing the urgency to address climate change as indicatedin the Fourth Assessment Report of the Intergovernmental Panel onClimate Change
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Key findings of the IPCCFourth Assessment Report:
1. Warming of the climate
system is unequivocal
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Observed changes
Global averagesea level
Northern hemispheresnow cover
Global averagetemperature
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Global temperature change
1900 1950 2000
Year
1
0.5
0
Models using onlynatural forcing
Models using bothnatural and
anthropogenic forcing
Observations
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The frequency of heavy precipitation events hasincreased over most land areas
- Rainfall in Mumbai (India), 2005:1 million people lost their homes
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Heat waves have become more frequentover most land areas
- Heat wave in Europe, 2003: 35 000 deaths
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Intense tropical cyclone activity has increasedin the North Atlantic since about 1970
- Hurricane Katrina, 2005: up to $200 billion cost estimate
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More intense and longer droughts have beenobserved over wider areas since the 1970s,particularly in the tropics and subtropics
Photocredit:GoodPlanet
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Key findings of the IPCC
Fourth Assessment Report:
2. Continued GHG emissions [...] wouldinduce many changes in the global climatesystem during the 21st century that would
very likely be larger than those observedduring the 20th century
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Carbon dioxide emissions
10000 5000 0
Time (before 2005)
-2
Global atmospheric
concentrations of
greenhouse gases (GHG)
increased markedly as a
result of human activities,
with an increase
of70% in 1970-2004
U.S. emissions have risen
by 14.7% in 1990-2006*
*Source: EPA, 2008
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Projected surface temperature changes(2090-2099 relative to 1980-1999)
Continued emissions would lead to further warming
of 1.1C to 6.4C over the 21st century
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 (oC)
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0 1 2 3 4 5o
WATER
Increased water availability in moist tropics and high latitudes
Decreasing water availability and increasing drought in mid-latitudes and semi-arid low latitudes
Hundreds of millions of people exposed to increased water stress
ECO-
SYSTEMS
Increased coral bleaching Most corals bleached Widespread coral mortality
Terrestrial biosphere tends towards a net carbon source as:15% 40% of ecosystems affected
Increasing species range shifts and wildfire risk
Ecosystem changes due to weakening of the meridionaloverturning circulation
FOOD
Complex, localised negative impacts on small holders, subsistence farmers and fishers
Tendencies for cereal productivity Productivity of all cerealsto decrease in low latitudes decreases in low latitudes
Tendencies for some cereal productivity Cereal productivity to decrease in
to increase at mid- to high latitudes some regions
COASTS
Increased damage from floods and storms
About 30% of global coastal wetlands lost
Millions more people experience coastal flooding each year
HEALTH
Increasing burden from malnutrition, diarrhoeal, cardio-respiratory, infectious diseases
Increased morbidity and mortality from heat waves, floods, droughts
Changed distribution of some disease vectors
Examples of impacts associated with
global average temperature change relative to 1980-1999
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Coastal communities and habitats will beincreasingly stressed by climate change impacts
interacting with development and pollution
Warming in western mountains is projected tocause decreased snowpack and reduced summer
flows, exacerbating competition for over-allocated
water resources
Increased number, intensity and duration of
heatwaves will have potential for adversehealth impacts
Impacts on North America
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People exposed to increased water stress by 2020: 120 million to 1.2 billion in Asia 12 to 81 million in Latin America 75 to 250 million in Africa
Expected impacts on poor regions
Possible yield reduction in agriculture:
30% by 2050 in Central and South Asia
30% by 2080 in Latin America 50% by 2020 in some African countries
Crop revenues could fall by 90% by 2100 in Africa
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Key findings of the IPCC
Fourth Assessment Report:
3. Neither adaptation nor mitigation
alone can avoid all climate changeimpacts; however, they cancomplement each other and
together can significantly reduce therisks of climate change
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Stabilisation scenarios
3.2 4.0
2.8 3.2
2.4 2.8
2.0 2.4
Global mean
temp. increase
(C)
2020 2060590 710
2010 2030535 590
2000 2020490 535
2000 2015445 490
Year CO2 needs
to peak
Stabilization
level
(ppm CO2-eq)
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Mitigation measures would induce 0.6% gain
to 3% decrease of GDP in 2030
Stabilisation
levels
(ppm CO2-eq)
Range of GDP
reduction
(%)
Reduction ofaverage annual
GDP growth
rates
(percentage pts)
445 - 535 < 3 < 0.12
535 - 590 0.2 2.5 < 0.1
590 - 710 -0.6 1.2 < 0.06
Costs of mitigation in 2030
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GDP withoutmitigation
GDP with
stringentmitigation
2030
GDP
TimeCurrent
Mitigation wouldpostpone GDP
growth by one yearat most over themedium term
Cost of mitigation
in 2030: max 3%of global GDP
Impacts of mitigation on GDP growth(for stabilisation scenario of 445-535 ppm CO2-eq)
Schematic ra h
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Healthco-benefits from reduced air pollution
Increased energysecurity
Increased agriculturalproduction and reducedpressure on natural ecosystems
More rural employment
Co-benefits of mitigation
Co-benefits provide the opportunity for
no-regrets policies and reduce mitigation costs
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Key findings of the IPCC
Fourth Assessment Report:
4. There is substantial [] potential for
the mitigation of global GHGemissions over the coming decades
that could [] reduce emissions
below current levels
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All stabilisation levels assessed
can be achieved by deployment of a portfoliooftechnologies that are currently available or
expected to be commercialised
in coming decades
This assumes appropriate andeffective incentives are in place for
their development, acquisition,deployment and diffusion
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Regulations and standards
Appropriate energy infrastructure investments
Research, development and demonstration
Key mitigation instruments,
policies & practices
Effective carbon-price signal
Taxes and charges
Change in lifestyles & consumption patterns
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Barack Obamas
New Energy for America plan (2008)
Create 5 million new green jobs by investing$150 billion over the next 10 years
Ensure 10% of electricity comes from renewablesources by 2012, and 25% by 2025
Get 1 million hybrid cars on the road by 2015
Implement an economy-wide cap-and-trade programto reduce greenhouse gas emissions 80% by 2050
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enable the achievement of globalstabilisation targets
US action on mitigation would:
ensure US competitiveness in a worldmarket dominated by low-carbon products
re-establish confidence in US leadershipon critical global issues
The need for US involvement
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Man did not weave the web of life,he is merely a strand in it.
Whatever he does to the web,he does to himself.
Chief Seattle, 1854