B. The Working Group II Fourth Assessment

The decision to produce a Fourth Assessment Report was taken by the 19th Session of the IPCC at Geneva in April 2002. The report was to be more focussed and shorter than before. The Working Group II contribution was to be finalised in mid-2007.

The IPCC Fourth Assessment is intended to be a balanced assessment of current knowledge. Its emphasis is on new knowledge acquired since the IPCC Third Assessment (2001). This required a survey of all published literature, including non-English language and ‘grey’ literature such as government and NGO reports.

Two meetings were held in 2003 to scope the Fourth Assessment, from which emerged the outline for the Working Group II Assessment submitted to IPCC Plenary 21 in November 2003 for approval and subsequent acceptance.

The Report has twenty chapters which together provide a comprehensive assessment of the climate change literature. These are shown in Table I.1. The opening chapter is on observed changes, and addresses the question of whether observed changes in the natural and managed environment are associated with anthropogenic climate change. Chapter 2 deals with the methods available for impacts analysis, and with the scenarios of future climate change which underpin these analyses. These are followed by the core chapters, which assess the literature on present day and future climate change impacts on systems, sectors and regions, vulnerabilities to these impacts, and strategies for adaptation. Chapters 17 and 18 consider possible responses through adaptation and the synergies with mitigation. The two final chapters look at key vulnerabilities, and the inter-relationships between climate change and sustainability.

Chapters 9 to 16 of the Working Group II Fourth Assessment consider regional climate change impacts. The definitions of these regions are shown in Table I.2.