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Findings: IPCC Assessment Reports

Since 1990, the IPCC has published its findings in Assessment Reports (ARs). Each comprehensively covers the many implications of climate change, including scientific, technical and socio-economic aspects. The Assessment Reports consists of reviews of the state of scientific understanding from three Working Groups and an integrating Synthesis Report that directly addresses key questions raised by policymakers.

In each of the first three reports since 1990, the evidence for and the degree of confidence that humans are the dominant factor influencing global climate has increased.1 The likelihood of other factors playing a key role in observed warming has decreased.

The Fourth Assessment Report (AR4) continues this trend.

Working Group I Report Released

On February 2, 2007, the IPCC released the summary of Working Group I of the Fourth Assessment Report. The Working Group I report is the most-up-to-date and authoritative summary of the scientific literature and understanding of global climate change. The IPCCC Working Group I report expressed decisively that global climate change is occurring as a result of human activities and will have significant impact on the earth’s natural systems.

Key findings include:

For a more detailed list of findings, see the National Center for Atmospheric Research.

Upcoming Reports

Additional reports are going to be released as part of the Fourth Assessment throughout 2007. Taken together, they will provide comprehensive and up-to-date information about climate change, its causes, impacts and possible response measures based on the latest scientific technical and socio-economic literature. About 500 lead authors, supported by hundreds of other contributors, were involved in drafting the Fourth Assessment Report.

The summary of Working Group II: Impacts, Adaptation and Vulnerability, is scheduled for release April 6, 2007 at the conclusion of meetings to be held in Brussels, Belgium.

The summary of Working Group III: Mitigation of Climate Change will be released May 4, 2007, Bangkok, Thailand.

A synthesis report will be approved in November, 2007 in Valencia, Spain.

1. Key conclusions from all three reports obtained from