THE Intergovernmental Panel on Climate Change (IPCC)

Human activities have already begun to affect global climate.

Scientists have learned much about climate and how it responds to human activities such as emissions of carbon dioxide and other “greenhouse gases.”

Nevertheless, great uncertainty remains.

Climate change challenges policymakers.

Some argue that it poses a risk of such serious damage that the lack of full scientific certainty should not be used as an excuse to postpone action.

Others regard the risk as manageable and not worth a major shift in the investment of financial and human resources.

Somehow, policymakers must sort through the evidence, weigh the costs and benefits, evaluate the risks, and decide on action.

Science has a role to play in informing wise policy.

Because the stakes are so high and the system so complex, policymakers cannot rely on on any single expert viewpoint.

Policymakers need an objective source of the most widely accepted scientific information about climate change, its effects, and possible response options.

The IPCC was established in 1988 to meet this need.

The World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) jointly established the IPCC.

It is important to understand that the IPCC is both governmental and scientific.

Establishing the IPCC

• 1979 First World Climate Conference, WMO.• 1985 Assessment of the Role of Carbon Dioxide and of

Other Greenhouse Gases in Climate Variations and Associated Impacts (UNEP, WMO, ICSU). Conclusion: we are headed to new climate extremes in the first half of the 21st C.

• 1988 IPCC established at WMO with UNEP governance.

Original IPCC Charge (1988)

1. Science of climate and climatic change

2. Social and economic impacts

3. Possible response strategies

4. International legal instruments

5. International convention on climate

IPCC does not conduct new research.

Its mandate is to assess, on a comprehensive, objective, open and transparent basis, the available scientific information in peer-reviewed literature.

IPCC reports are policy-relevant but not policy-prescriptive or policy-driven.

The IPCC has produced four major Assessment Reports (1990, 1995, 2001, 2007).

Each includes Summaries for Policymakers, written so as to be comprehensible to the non-specialist.

These are published in all six UN languages.

The 1990 IPCC First Assessment Report confirmed the scientific basis for concern about climate change.

It helped persuade governments to adopt the UN Framework Convention on Climate Change, signed at the Earth Summit in Rio de Janeiro (1992).

The 1995 IPCC Second Assessment Report contributed crucially to the negotiations that led to the adoption of the Kyoto Protocol in 1997.

The Kyoto Protocol, which would restrict emissions of greenhouse gases, has not yet come into force, mainly because of opposition from the United States.

IPCC Summary Statements

•FAR, 1990: The unequivocal detection of the enhanced greenhouse effect is not likely for a decade or more.

•SAR, 1995: The balance of evidence suggests a discernible human influence on global climate.

•TAR, 2001: Most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.

•AR4, 2007: Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.

•AR5, 2011: AGW very, very likely? – No, Aiming for more applied science, what should we do about climate change?

IncreasingResolutionFAR 1990SAR 1995TAR 2001AR4 2007

The WorldIn GlobalClimateModels

AR4 WG2 SPM• The impacts of climate change are, with high confidence

(80%), expected to be most significant when and where they occur in the context of multiple stresses from other sources such as poverty, unequal access to resources, food insecurity, and environmental degradation. The intensities of these interactions vary from place to place and over time along specific development pathways.

• Medium confidence (50%) global estimates of the number of people adversely affected by climate change by 2080: water scarcity 1-3 billion, hunger 200-600 million, coastal flooding 2-7 million.

AR4 WG2 fresh water resources

What Students (and Professors) Can Do

Climate change is real and serious. It’s not a hoax. It won’t go away. It needs thoughtful action.

Everybody can play a role. Be better informed. Keep this issue prominent. The USA can lead.

Scientific illiteracy helps spread misinformation. Educate kids (& corporations & politicians too).

Get comfortable with sensitive issues. Population is a driver. Personal values matter. Think.

www.ipcc.ch