Since the last ice age, when ice enveloped most of the northern continents, the earth has warmed by about five degrees. Within a century, it is likely to warm by another four or five. This revolution in our climate will have immense and mostly harmful effects on the lives of people not yet born. We are inflicting this harm on our descendants by dumping greenhouse gases into the atmosphere. We can mitigate the harm a little by taking measures to control (...) our emissions of these gases, and to adapt to the changes by, for instance, building sea walls around coastlines threatened by rising sea levels. But these measures will be very expensive, and the costs will be born by us, the present generation, whereas the benefits will come to future generations. How much should we sacrifice for the sake of the future? Economists and philosophers have independently worked on the question of our responsibility to future generations. This book brings their work together and applies it to global warming. It suggests a programme for future research on the economic and ethical issues. The book is intended for economists, and for philosophers and other social scientists who have a little knowledge of economic methods. (shrink)

The climate change problem must be thought of in terms of risk, not certainty. There are many well-established elements of the problem that carry considerable confidence whereas some aspects are speculative. Therefore, the climate problem emerges not simply as a normal science research issue, but as a risk management policy debate as well. Descriptive science entails using empirical and theoretical methods to quantify the two factors that go into risk assessment: “What can happen?” and “What are the odds?” (Probability x (...) Consequences). Policymakers should, in turn, take that information and use it to make value judgments about what is safe, what is dangerous, what is fair. To make these judgments, policymakers need to know the probabilities that experts assign to various possible outcomes in order to make risk management decisions to hedge against unsafe, dangerous and unfair outcomes. The climate debate needs to be reframed away from absolute costs—or benefits—into relative delay times to achieve specific caps or to avoid crossing specific agreed “dangerous” climate change thresholds. Even in most optimistic scenarios, CO2 will stabilize at a much higher concentration than it has reached today, and temperature will rise accordingly. It will take even longer for sea level rise from thermal expansion and the melting of polar ice to occur, but what is most problematic is that how we handle our emissions now and in the next five decades preconditions the sustainability of the next millennium. (shrink)

There are many uncertainties concerning climate change, but a rough international consensus has emerged that a doubling of atmospheric carbon dioxide from its pre-industrial baseline is likely to lead to a 2.5 degree centigrade increase in the earth's mean surface temperature by the middle of the next century. Such a warming would have diverse impacts on human activities and would likely be catastrophic for many plants and nonhuman animals. The author's contention is that the problems engendered by the possibility of (...) climate change are not purely scientific but also concern how we ought to live and how humans should relate to each other and to the rest of nature; and these are problems of ethics and politics. (shrink)

Very few moral philosophers have written on climate change.1 This is puzzling, for several reasons. First, many politicians and policy makers claim that climate change is not only the most serious environmental problem currently facing the world, but also one of the most important international problems per se.2 Second, many of those working in other disciplines describe climate change as fundamentally an ethical issue.3.

With very advanced technology, a very large population of people living happy lives could be sustained in the accessible region of the universe. For every year that development of such technologies and colonization of the universe is delayed, there is therefore a corresponding opportunity cost: a potential good, lives worth living, is not being realized. Given some plausible assumptions, this cost is extremely large. However, the lesson for standard utilitarians is not that we ought to maximize the pace of technological (...) development, but rather that we ought to maximize its safety, i.e. the probability that colonization will eventually occur. This goal has such high utility that standard utilitarians ought to focus all their efforts on it. Utilitarians of a ‘person-affecting’ stripe should accept a modified version of this conclusion. Some mixed ethical views, which combine utilitarian considerations with other criteria, will also be committed to a similar bottom line. (shrink)

Science can reinforce the healthy aspects of the politics of the policy process, to identify and further the public interest by discrediting policy options serving only special interests and helping to select among “science-confident” and “hedging” options. To do so, scientists must learn how to manage and communicate the degree of uncertainty in scientific understanding and prediction, lest uncertainty be manipulated to discredit science or to justify inaction. For natural resource and environmental policy, the institutional interests of government agencies, as (...) well as private interests, pose challenges of suppression, over-simplification, or distortion of scientific information. Scientists can combat these maneuvers, but must also look inward to ensure that their own special interests do not undermine the usefulness of science. (shrink)

In this century a number of events could extinguish humanity. The probability of these events may be very low, but the expected value of preventing them could be high, as it represents the value of all future human lives. We review the challenges to studying human extinction risks and, by way of example, estimate the cost effectiveness of preventing extinction-level asteroid impacts.

This commentary argues in defence of equal per capita emissions with historical accountability as a general rule for allocating the right to emit greenhouse gases. Historical accountability takes into account historical inequalities in per capita emissions. Implicitly it gives every human being an equal share of the global resource atmosphere, independent of place or time. Three reasons are put forward to argue why historical accountability should be the guiding principle for an international agreement allocating rights of emissions. In addition, as (...) it has been dismissed by many scholars, six arguments are given to refute objections against historical accountability. (shrink)