17 Jul 2001 1

Climate Change 2001:

Impacts, Adaptation and Vulnerability

Overview of WGII Findings Neil Leary

IPCC Special Event, CoP6 Part II, Bonn-Germany, 17 July 2001

17 Jul 2001 2

Preparation of the WGII Report

Written by 183 Lead and 243 Contributing Authors Authors met multiple times during the 2 1/2 year assessment

Peer Reviewed by scientific and technical experts by governments

Report revised to address reviewer comments 33 Review Editors oversaw the review/revision process

Accepted at 6th Session of IPCC WGII as “a comprehensive, objective, and balanced view” Session attended by government delegates of 100 nations

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Preparation of the Summary for Policymakers (SPM)

60 authors of the WGII Report drafted the SPM A first draft was circulated to all lead authors, external

reviewers and governments prior to a meeting of authors The SPM was revised by authors based on written comments

and discussion at the meeting

The revised draft was circulated to all governments for their consideration Written comments submitted again The authors met and revised the SPM again

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Approval of WGII SPM

The SPM was approved at 6th Session of IPCC WGII Approval signifies agreement that the SPM is consistent with

the full report

Changes were made to the SPM at the WG Session to clarify the language and to highlight material of particular relevance to policymakers

40 authors participated in the WG Session Authors ensured that changes were scientifically valid and that the final document was consistent with the full report

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General Findings from WGII

Temperature increases have already affected physical and biological systems

Preliminary indications that human systems have been affected by increases in floods and droughts

Natural systems are vulnerable and some will be irreversibly damaged

Many human systems are sensitive to climate change and some are vulnerable

Projected changes in climate extremes could have major consequences

Risks of large-scale and possibly irreversible impacts are yet to be reliably quantified

Adaptation is a necessary complement to mitigation

Those with least resources have least capacity to adapt and are most vulnerable

Adaptation, sustainable development, and enhancement of equity can be mutually reinforcing.

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Temperature changes have already affected many physical and biological systems

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Types of Changes Seen

Animals and PlantsRange shifts (latitudinal or altitudinal)

Abundance changes

Change in growing season length

Earlier flowering; emergence of insects; migration and egg-laying in birds

Morphology shifts (e.g. body & egg sizes)

Hydrology and Glaciers

Glacier shrinkage

Permafrost thawing

Later freeze & earlier break up of river and lake ice

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Numbers of species or processes changing

-100

0

100

200

300

in direction expected

opposite to direction expected

Amphibians

Vegetation

Invertebrates

Birds

Glaciers/ hydrology

Mammals

90% of physical and 80% of biological cases identified are changing in the direction consistent with well-established temperature relationships.

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There are preliminary indications that some human systems have been affected by increases in floods and droughts

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Catastrophic weather-related losses increased 10-fold from 1950s

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Natural systems are vulnerable to climate change and some will be irreversibly damaged

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Endorheic lakes: e.g. Caspian, Aral seas

Tropical glaciers and related water flows

Ecosystems with migration barriers - e.g. Montane ecosystems, Cape Floral Kingdom

Coral Reefs (1% of ocean area, 30% of marine species)

Mangroves- e.g. Sundarbans, last habitat of Royal Bengal Tiger

Endangered species

Some Threatened Systems

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Many human systems are sensitive to climate change and some are vulnerable

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Human Systems

Vulnerabilities

Food and water security

Incomes and livelihoods

Human health

Infrastructure

Sensitive Systems

Water resources

Agriculture, forestry, fisheries

Human settlements

Industry, energy, financial services

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Projected changes in climate extremes could have major consequences

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Changes in extreme events (temperature)

Higher maximum temperatures, more hot days and heat waves over nearly all land areas (Very likely)

Increased death and serious illness in older age groups and urban poorIncreased heat stress in livestock and wildlifeShift in tourist destinations Increased risk of damage to a number of cropsIncreased electric cooling demand and reduced energy supply reliability

Higher [Increasing] minimum temperatures, fewer cold days, frost days and cold waves over nearly all land areas (Very likely)

Decreased cold-related human morbidity and mortalityDecreased damage to a number of crops, and increased risk to othersExtended range and activity of some pest and disease vectorsReduced heating energy demand

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Changes in extreme events (hydrological)

More intense precipitation events (Very likely, over many areas)

Increased flood, landslide, avalanche, and mudslide damageIncreased soil erosionIncreased flood runoff could increase recharge of some floodplain aquifersIncreased pressure on government and private insurance systems and disaster relief

Increased summer drying over most mid-latitude continental interiors and associated risk of drought (Likely)

Decreased crop yieldsIncreased damage to building foundations caused by ground shrinkageDecreased water resource quantity and qualityIncreased risk of forest fire

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Risks of large scale and possibly irreversible impacts are yet to be reliably quantified

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Sea level rise fromdisintegration of Greenlandand West Antarctic Ice Sheets

Substantial slowing or collapse ofocean circulation that transports

heat to North Atlantic

Very low likelihood in 21st century but increases with rate, magnitude and duration of climate change

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Article 2: The ultimate objective of this Convention … is to achieve … stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

Synthesis

Reasons for concernRisks to Unique and Threatened Systems

Risks from Extreme Climate Events

Distribution of Impacts

Aggregate Impacts

Risks from Future Large-Scale Discontinuities

A multi-dimensional basis for providing scientific and technical information relevant to policy decisions on “dangerous” levels of interference with the climate system.

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Comparing reasons for concern

Year

Glo

bal m

ean

war

min

g o C

I Risks to Unique and Threatened SystemsII Risks from Extreme Climate EventsIII Distribution of ImpactsIV Aggregate ImpactsV Risks from Future Large-Scale Discontinuities

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Summary

For small amounts of climate change, benefits are projected for some sectors and regions, although the majority of people are likely to be adversely affected

For larger amounts of change, projected benefits diminish, projected damages increase, and risks associated with large scale discontinuities become more important

The WG II contribution to the IPCC Third Assessment Report provides the clearest evidence yet that the effects of climate change will be widespread and should be taken seriously.