Our understanding of climate and its role in human affairs has changed markedly over recent years, as have climate observation systems and modelling capabilities. Reliance on recent weather statistics to provide a guide for future climate is no longer viable. Evidence of human-induced climate change has placed climate high on political and the media agendas. This text provides an account of what we know about climate and changing climates at the end of the 20th century. Integrating the historical and geographical dimensions of climate, the crucial link between past and future climatic conditions is examined through the geographical lens of the British Isles. Climates of past ages are reconstructed and full descriptions of the present climate are illustrated by graphs, maps and images. Important climate data sets are provided. Marking the 25th anniversary of the Climatic Research Unit, this book distils much of the leading research of present and recent members of the unit and presents a view of climatic change and prospects for the next millenium and beyond.