Although the task of formulating an appropriate policy response to the problem of anthropogenic climate change is one that raises a number of very difficult normative issues, environmental ethicists have not played an influential role in government deliberations. This is primarily due to their rejection of many of the assumptions that structure the debates over policy. This book offers a philosophical defense of these assumptions, in order to overcome the major conceptual barriers to the participation of philosophers in these debates. There are five important barriers: First, the policy debate presupposes a stance of liberal neutrality, as a result of which it does not privilege any particular set of environmental values over other concerns. Second, it assumes ongoing economic growth, along with a commitment to what is sometimes called a weak sustainability framework when analyzing the value of the bequest being made to future generations. Third, it treats climate change as fundamentally a collective action problem, not an issue of distributive justice. Fourth, there is the acceptance of cost-benefit analysis, or more precisely, the view that a carbon pricing regime should be guided by our best estimate of the social cost of carbon. And finally, there is the view that when this calculation is undertaken, it is permissible to discount costs and benefits, depending on how far removed they are from the present. This book attempts to make explicit and defend these presuppositions, and in so doing offer philosophical foundations for the debate over climate change policy.