This is not a book about climate science. Rather it analyses why some people dispute the reality, reliability and reasonableness of this science. The validity of the scientifi c consensus is therefore taken as a given, solely in order to analyse the views of climate change sceptics who dispute it. Nevertheless, most biological and environmental scientists do agree that the scale of much human activity now exceeds the capacity of our environment to sustain it, or to recycle the waste it generates. Using a river as a source of water, a laundry and a toilet may be possible if you live in a sparsely populated wilderness. If you live in a slum, however, it is likely to lead to your premature death. As such, many activities have become problematic simply because of the rate at which we are carrying them out. This includes pumping carbon dioxide into the atmosphere. Therefore this book addresses the philosophical roots of scepticism, its possible misappropriation for ideological reasons, and the psychological causes of denial. It concludes by suggesting that ending this denial of science is an essential next step toward a sustainable future in a post-carbon era.