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Key Findings of the IPCC Fourth Assessment Report

WMO UNEP

R. K. PachauriChairman, IPCC

Director-General, TERI

Brussels 31st March 2009

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The Intergovernmental Panel on Climate Change

(IPCC)

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The IPCC

“The General Assembly […] endorses action of the World Meteorological Organization and the United

Nations Environment Programme in jointly establishing an Intergovernmental Panel on Climate

Change to provide international coordinated scientific assessments of the magnitude, timing and potential environmental and socio-economic impact of climate change and realistic response strategies […].”

United Nations General Assembly 43rd session resolution, 6th December 1988

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1. Experts review the first draft of the report

2. Governments and experts review the second draft of the report and the draft Summary for Policymakers

3. Governments review word-by-word the revised 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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Warming of the climate system is

unequivocal, as is now evident

from observations of increases in

average air and ocean temperatures,

widespread melting of snow and ice,

and rising average sea level

I. Observed changes in climate

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Global averagesea level

Northernhemispheresnow cover

Global average temperature

I. Observed changes in climate

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I. Observed changes in climate

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II. Causes of change

Global GHG emissions due to human activities have grown since pre-industrial times, with an increase of 70% between 1970 and 2004

CO2 annual emissions grew by about 80% between 1970 and 2004

Most of the observed increase in temperatures since the mid-20th century is very likely due

to the increase in anthropogenic GHG concentrations

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II. Causes of change

Observed patterns of warming are simulated only by models that include anthropogenic forcings

Global temperature change

1900 1950 2000

Year

Tem

per

atu

re a

no

mal

y

1

0.5

0

Models using only natural forcing

Models using both natural and anthropogenic forcing

Observations

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III. Projected climate change and impacts

Continued emissions would lead to further warming of 1.8ºC to 4ºC 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)

Projected surface temperature changes (2090-2099 relative to 1980-1999)

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20-30% of species are likely to be at risk of extinction if increases in warming exceed 1.5-2.5°C

Partial loss of ice sheets on polar land could imply metres of sea level rise, major changes in coastlines and inundation of low-lying areas

Large scale and persistent changes in Meridional Overturning Circulation would have impacts on marine ecosystem productivity, fisheries, ocean CO2 uptake and terrestrial vegetation

III. Projected climate change and impactsClimate change could lead to some abrupt

or irreversible impacts

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III. Projected climate change and impacts Systems and sectors

likely to be especially affectedParticular ecosystems: tundra, boreal forest, mountain regions, mediterranean-type ecosystems, tropical rainforests; mangroves and salt marshes; coral reefs; the sea ice biome

Water resources in some dry regions at mid-latitudes and in the dry tropics, due to changes in rainfall and evapo-transpiration, and in areas dependent on snow and ice melt

Human health in populations with low adaptive capacity

Low-lying coastal systems, due to threat of sea level rise and increased risk from extreme weather events

Agriculture in low-latitudes, due to reduced water availability

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III. Projected climate change and impacts Regions likely to be especially affected

The Arctic, because of the impacts of high rates of warming on natural systems and human communities

Asian and African megadeltas, due to large populations and high exposure to sea level rise, storm surges and river flooding

Small islands, which are highly vulnerable to projected sea level rise

Africa, because of low adaptive capacity and projected climate change impacts

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III. Projected climate change and impactsNegative impacts in Europe

Inland and coastal flooding

Health risks due to heat-waves

Reduction of water availability and crop productivity in South Europe

Species losses and reduced snow cover in mountains

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IV. Adaptation and mitigation options

Adaptation can reduce vulnerability especially when it is embedded within broader sectoral initiatives

Adaptive capacity is intimately connected to social and economic development

Even societies with high adaptive capacity remain vulnerable to climate change

But adaptation alone is not expected to cope with all the projected effects of climate change

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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 that investment flows, technology transfer and incentives are in place for technology development

IV. Adaptation and mitigation options

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Efficient lighting; efficient appliances; improved insulation; solar heating and cooling; alternatives for fluorinated gases in insulation and appliances

Efficiency; fuel switching; renewables; combined heat and power; nuclear power; early applications of CO2 capture & storage

Energy Supply

TransportMore fuel efficient vehicles; hybrid vehicles; biofuels; modal shifts from road transport to rail and public transport systems

Buildings

IV. Adaptation and mitigation options Key mitigation technologies

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IV. Adaptation and mitigation optionsKey mitigation instruments, policies and practices:

Regulations and standards

Effective carbon-price signal

Appropriate energy infrastructure investments

Research, development and demonstration

Taxes and charges

Changes in lifestyle & management practices

International and regional cooperation

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V. Mitigation targets

Stabilizationlevel

(ppm CO2-eq)

Global mean temp.

increase (ºC)

Year CO2

needs to peak

Global sea level rise above pre- industrial from

thermal expansion

(m)

445 – 490 2.0 – 2.4 2000 – 2015 0.4 – 1.4

490 – 535 2.4 – 2.8 2000 – 2020 0.5 – 1.7

535 – 590 2.8 – 3.2 2010 – 2030 0.6 – 1.9

590 – 710 3.2 – 4.0 2020 – 2060 0.6 – 2.4

Characteristics of stabilisation scenarios

Mitigation efforts over the next two to three decades will have a large impact on opportunities to achieve

lower stabilisation levels

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GDP without mitigation

GDP with stringent mitigation

2030

GDP

TimeCurrent

Mitigation would postpone GDP growth by one year at most over the medium 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 graph

V. Mitigation targets

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V. Mitigation targets

In 2050, global average costs for mitigation are between a 1% gain and 5.5% decrease of global GDP

- less than 0.12 percentage points in annual GDP

Costs of impacts of climate change will increase as temperatures increase

Choices about the scale and timing of mitigation involve balancing the economic costs of more rapid emission

reductions against the medium and long term risks of delay

Mitigation actions can result co-benefits that may offset a substantial fraction of mitigation costs

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V. Mitigation targets

Developed countries need to significantly reduce their emissions below 1990 levels:

10-40% by 2020

40-95% by 2050

Developing country emissions need to deviate below their projected baseline within the next few decades

Beyond the Kyoto Protocol

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Our settlements and communities presently lack the resilience to enable them to weather future energy and environmental shocks

The only way forward is creating a sober society, where resources are more valorised and consumption is reduced

Atmosphere, land, water, biodiversity and human society are linked in a complex web of interactions and feedbacks

By unleashing our individual & collective genius, we can build ways of living that are more connected, more enriching and that recognise the biological limits of our planet

VI. Towards a new development path

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VI. Towards a new development pathThe dominant path to industrialization has been

characterized by high concurrent GHG emissions

Committing to alternative development paths would require major changes in areas other than

climate change:Economic structure

Technology

Geographical distribution of activities

Consumption patterns

Urban design and transport infrastructure

Demography

Institutional arrangements and trade patterns

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Key policies

Improving scientific understanding of the issues at stake

Promoting research & development and technology transfer

Informing and educating

Mainstreaming environmental policies in decision making

Internalising the environmental costs of economic activity

E.g. effective carbon-price signal

Effective policies are those that provide long-term signals and incentives on a predictable basis

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Be the change you want to see in the worldGandhi was once asked if he expected India to attain the same standard of living as Britain. He replied:

It took Britain half the resources of the planet to achieve this prosperity. How many planets will a country like India require!