Since the last ice age, when ice enveloped most of the northern continents, the earth has warmed up by about five degrees. Within a century, it is likely to warm by another four or five, because of the greenhouse gases that we are dumping into the atmosphere. This will have immense and mostly harmful effects on the lives of people not yet born. How much should the present generation be prepared to pay to mitigate these harmful effects? How much should we sacrifice for the sake of the future? In Counting the Cost of Global Warming, John Broome surveys the ways in which economists and philosophers have tackled the question of our responsibility to future generations, with special reference to the economic and ethical issues raised by the threat of global warming. His conclusions on the extent to which we are entitled to 'discount' the long term future make essential reading for economists, philosophers and social scientists who are concerned with policy in this vital area.