IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Synthesis Report


The Intergovernmental Panel on Climate Change (IPCC) was jointly established in 1988, by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), with the mandate to assess scientific information related to climate change, to evaluate the environmental and socio-economic consequences of climate change, and to formulate realistic response strategies. The IPCC multivolume assessments have since then played a major role in assisting governments to adopt and implement policies in response to climate change, and in particular have responded to the need for authoritative advice of the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC), which was established in 1992, and its 1997 Kyoto Protocol.

Since its establishment, the IPCC has produced a series of Assessment Reports (1990, 1995, 2001 and this one in 2007), Special Reports, Technical Papers and Methodology Reports, which have become standard works of reference, widely used by policymakers, scientists, other experts and students. The most recent publications include a Special Report on “Carbon Dioxide Capture and Storage” and one on “Safeguarding the Ozone Layer and the Global Climate System”, published in 2005, and the “Guidelines for National Greenhouse Gas Inventories” re-edited in 2006. A Technical Paper on “Climate Change and Water” is under preparation.

This Synthesis Report (SYR), adopted in Valencia, Spain, on 17 November 2007, completes the four-volume Fourth Assessment Report (AR4), which was released in various steps throughout the year under the title “Climate Change 2007”. It summarises the findings of the three Working Group reports and provides a synthesis that specifically addresses the issues of concern to policymakers in the domain of climate change: it confirms that climate change is occurring now, mostly as a result of human activities; it illustrates the impacts of global warming already under way and to be expected in future, and describes the potential for adaptation of society to reduce its vulnerability; finally it presents an analysis of costs, policies and technologies intended to limit the extent of future changes in the climate system. 

The AR4 is a remarkable achievement involving more than 500 Lead Authors and 2000 Expert Reviewers, building on the work of a wide scientific community and submitted to the scrutiny of delegates from more than one hundred participating nations. It is the result of the enthusiasm, dedication, and cooperation of experts from many different but related disciplines. We would like to express our gratitude to all of them, to the Members of the IPCC Bureau, to the staff of the Technical Support Units, particularly of the Technical Support Unit for the IPCC Synthesis Report in The Energy and Resources Institute (TERI) in Delhi, to Dr Renate Christ, Secretary of the IPCC, and to the Secretariat staff. 

We acknowledge with gratitude the governments and organisations that contribute to the IPCC Trust Fund and provide support to experts in different ways. The IPCC has been especially successful in engaging in its work a large number of experts from the developing countries and countries with economies in transition; the Trust Fund enables extending financial assistance for their travel to IPCC meetings. We also acknowledge the cooperative spirit in which all government delegates have worked together in the IPCC Sessions to reach a meaningful and powerful consensus.

Finally, we would like to thank the Chairman of the IPCC, 
Dr Rajendra K. Pachauri, for leading tirelessly and with dedication the effort of all. This is particularly appropriate at this time as the IPCC as a whole, under his guidance, has been awarded the 2007 Nobel Peace Price.

We would also like at this occasion to express deep recognition and sorrow in remembrance of Prof. Bert Bolin, who led the way twenty years ago as first Chairman of IPCC, and who sadly passed away on 30 December 2007 after a brilliant career in meteorology and climate science.

Michel Jarraud

Secretary General 

World Meteorological Organization

Achim Steiner

Executive Director

United Nations Environmental Programme