Few areas of science have such profound implications for public policy and society as the study of climate change. As one consequence, scientists who may have begun their careers in relative backwaters of research now find themselves thrown into the limelight. Scientific points, and occasional errors, have become the subject of emotive debate and strong media interest. Frequently this has generated more heat than light, with polarised and ill-informed debates across the blogosphere - and indeed at times in the mainstream media. My aim in developing these web pages is to set out what I believe to be key aspects of the scientific evidence on climate change.