Climate ethics has been concerned with polluter pays, beneficiary pays and ability to pay principles, all of which consider climate change as a single negative externality. This paper considers it as a constellation of externalities, positive and negative, with different associated demands of justice. This is important because explicitly considering positive externalities has not to our knowledge been done in the climate ethics literature. Specifically, it is argued that those who enjoy passive gains from climate change owe gains not to (...) the net losers, but to the emitters, just as the emitters owe compensation to the net losers for the negative externality. This is defended by appeal to theoretical virtues and to the social benefits of generating positive externalities, even when those positive externalities are coupled with far greater negative externalities. We call this the Polluter Pays, Then Receives ('PPTR', or 'Peter') Principle. This principle is then applied at two levels in the context of Canada. [Open access]. (shrink)

This chapter introduces several distinctions relevant to what is called the “discounting problem”, since the issue is how (future) costs and benefits are discounted to make them comparable in present terms. The author defends the claim that there are good reasons to adopt Ramsey-style discounting in the context of climate change: the Ramsey rule is robust, flexible, and well-understood. An important distinction involved in discounting—“descriptivism” and “prescriptivism”—is discussed. It is argued that, even if we adopt prescriptivism, and accept that this (...) means there is need for moral experts in parameter assignments, there is a significant issue. The type of moral expertise required for the discounting problem will not involve knowledge of moral theory—thus making moral philosophy unhelpful in terms of making particular parameter assignments, despite these being substantive moral judgments. (shrink)

Ideal carbon tax policy is internationally coordinated, fully internalizes externalities, redistributes revenues to those harmed, and is politically acceptable, generating predictable market signals. Since nonideal circumstances rarely allow all these conditions to be met, moral issues arise. This paper surveys some of the work in moral philosophy responding to several of these issues. First, it discusses the moral drivers for estimates of the social cost of carbon. Second, it explains how national self-interest can block climate action and suggests international policies—carbon (...) border tax adjustments and carbon clubs—that can help address these concerns. Third, it introduces some of the social science literature about the political acceptability of carbon taxes before addressing a couple common public concerns about carbon taxes. Finally, it introduces four carbon revenue usage options, arguing that redistributive and climate compensation measures are most morally justified. [Open access]. (shrink)

Discounting future costs and benefits is often defended on the ground that our descendants will be richer. Simply to treat the future as better off, however, is to commit an ecological fallacy. Even if our descendants are better off when we average across climate change scenarios, this cannot justify discounting costs and benefits in possible states of the world in which they are not. Giving due weight to catastrophe scenarios requires energetic action against climate change.

Utility discounting in intertemporal economic modelling has been viewed as problematic, both for descriptive and normative reasons. However, positive utility discount rates can be defended normatively; in particular, it is rational for future utility to be discounted to take into account model-independent outcomes when decision-making under risk. The resultant values will tend to be smaller than descriptive rates under most probability assignments. This also allows us to address some objections that intertemporal considerations will be overdemanding. A principle for utility discount (...) rates is suggested which is rooted in probability discounting. Utility discounting is defended against objections from Parfit (1984) and Broome (2005); Broome (2012). A sample utility discount rate is estimated. [Open access]. (shrink)

This paper defends the claim that mere temporal proximity always and without exception strengthens certain moral duties, including the duty to save – call this view Robust Temporalism. Although almost all other moral philosophers dismiss Robust Temporalism out of hand, I argue that it is prima facie intuitively plausible, and that it is analogous to a view about special obligations that many philosophers already accept. I also defend Robust Temporalism against several common objections, and I highlight its relevance to a (...) number of practical policy debates, including longtermism. My conclusion is that Robust Temporalism is a moral live option, that deserves to be taken much more seriously in the future. (shrink)

This paper distinguishes between five different approaches to social discount rates in climate change economics, criticizes two of these, and explains how the other three are to some degree mutually compatible. It aims to shed some new light on a longstanding debate in climate change economics between so-called “descriptivists” and “prescriptivists” about social discounting. The ultimate goal is to offer a sketch of the conceptual landscape that makes visible some important facets of the debate that very often go unacknowledged.

In this paper, we argue that our moral concern for future well-being should reduce over time due to important practical considerations about how humans interact with spacetime. After surveying several of these considerations (around equality, special duties, existential contingency, and overlapping moral concern) we develop a set of core principles that can both explain their moral significance and highlight why this is inherently bound up with our relationship with spacetime. These relate to the equitable distribution of (1) moral concern in (...) a universe that we can only causally affect in one temporal direction; (2) access to the benefits from using spacetime as a resource; and (3) the burdens of care given (1) and (2). We conclude by considering the practical implications of our argument and find that, while it is often assumed that a preference for present over future well-being weakens the case for existential risk mitigation, this likely is not the case. (shrink)

The social cost of carbon (SCC) is a central concept in climate change economics. This chapter explains the SCC and investigates it philosophically. As is widely acknowledged, any SCC calculation requires the analyst to make choices about the infamous topic of discount rates. But to understand the nature and role of discounting, one must understand how that concept—and indeed the SCC concept itself—is yoked to the concept of a value function, whose job is to take ways the world could be (...) across indefinite timespans and to rank them from better to worse. A great deal, therefore, turns on the details of the value function and on just what is meant by “better” and “worse.” This chapter seeks to explicate these and related issues, and then to situate them within the evolving landscape of federal climate policy in the United States. (shrink)

This paper reviews debates related to the social cost of carbon (SCC) and the challenge of pricing uncertain damages that will occur only in the future. They often revolve around the pure time preference rate, which reflects how much one favors present over future well-being. The SCC measures the marginal cost of the impact on economic growth caused by the emission of a quantity of greenhouse gases equivalent to an additional ton of carbon dioxide (tCO2eq). There is significant variance among (...) estimates of the SCC; one of the reasons for it is a disagreement on how to bring future damages to present values, especially over the so-called "delta parameter" – the pure time preference rate – of the corresponding discount function. On the one hand, the descriptive approach, associated with William Nordhaus, proposes to use the time preference empirically observed among individuals, which would result in a significant limitation of the present value attributed to the distant future. On the other hand, the normative approach, associated with Nicholas Stern, proposes to treat everyone impartially, in every generation, and so implies transferring more resources to future generations. In the limit, assuming exponential population growth, it would lead to a philosophical stance akin to the so-called "longtermism" (as defended by William MacAskill in What we owe the future). In addition, the analysis points out obstacles to using the SCC to price carbon for climate policies. These include aspects related to economic methodology (such as ecological economics critiques of welfarist accounts of intergenerational allocations) as well as political philosophy. Thus, challenges related to uncertainty about socioeconomic development trajectories, intergenerational justice, and public reason become key. Finally, we present the target-consistent pricing approach, where one calculates a carbon price compatible with specific mitigation targets – an alternative to SCC methodologies. This approach is advocated as a way to avoid the uncertainty and the disagreements associated with the SCC, emphasizing the importance of meeting goals set by binding political decisions – such as the Paris Agreement. (shrink)

We discuss how transgenerational communitarianism deals with public decisions involving tradeoffs between different generations’ wellbeing and having global consequences. Policies for tackling climate change are an example. Although there is a natural, evolutionary, basis for intergenerational altruism, most people lack the competencies for constituting a transgenerational community. Moreover, greater attention to future generations’ wellbeing need not substitute for collective action: a lower discount rate reflecting a stronger concern for future generations may even worsen their wellbeing. Finally, in a world of (...) irreducible value pluralism, there is no community of persons sharing moral values that can legitimize common policies for addressing global problems: only the common interest of avoiding destructive consequences may motivate collective action to face problems like climate change. (shrink)