Counting the cost of global warming: A report to the Economic and Social Research Council on research by John Broome and David Ulph
London, 1992
Abstract
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.
Quotes from this work
Global warming is disconcerting in one respect. It seems inevitable that its consequences will be large, just because of the unprecedented size and speed of the temperature changes. Yet it is very hard to know just what these large consequences will be.
Total and average utilitarianism are very different theories, and where they differ most is over extinction. If global warming extinguishes humanity, according to total utilitarianism, that would be an inconceivably bad disaster. The loss would be all the future wellbeing of all the people who would otherwise have lived. On the other hand, according to at least some versions of average utilitarianism, extinction might not be a very bad thing at all; it might not much affect the average wellbeing of the people who do live. So the difference between these theories makes a vast difference to the attitude we should take to global warming. According to total utilitarianism, although the chance of extinction is slight, the harm extinction would do is so enormous that it may well be the dominant consideration when we think about global warming. According to average utilitarianism, the chance of extinction may well be negligible.