Climate change 2001: the scientific basis - working group 1

The Third Assessment Report of Working Group I of the Intergovernmental Panel on Climate Change (IPCC) builds upon past assessments and incorporates new results from the past five years of research on climate change1. Many hundreds of scientists2 from many countries participated in its preparation and review.This Summary for Policymakers (SPM), which was approved by IPCC member governments in Shanghai in January 20013, describes the current state of understanding of the climate system and provides estimates of its projected future evolution and their uncertainties. Further details can be found in the underlying report, and the appended Source Information provides cross references to the report's chapters.