Controversies about time discounting loom large in decisions about climate change. Prominently, a particularly controversial debate about time discounting in climate change decision-making has been conducted within climate economics, between the authors of Stern et al. and their critics :977–981, 2006; Weitzman in J Econ Lit XLV:703–724, 2007; Nordhaus in J Econ Lit XLV:686–702, 2007). The article examines the role of values in this debate. Firstly, it is shown that time discounting is a case in which values are key because (...) it is at heart an ethical problem. Secondly, it is argued that time discounting in climate economics is a case of economists making frequent and routine references to ethical values and indeed conduct ethical debates with each other. Thirdly, it is argued that there is evidence for deep and pervasive entanglement between facts and values in the prevalent methodologies for time discounting. Finally, it is argued that this means that economists have given up the ‘value-free ideal’ concerning time discounting, and discussed how the current methodology of time discounting in economics can be improved. (shrink)

Social thinkers frequently remind us that people differ on what constitutes personal well-being, but that even when they don't differ, they disagree over the extent to which one person's well-being can be permitted to be traded off against another's. They tell us that political differences are to be traced to differences in people's conceptions of personal and social well-being. We are given to understand, in other words, that people's ethics differ.

I discuss three families of methodologies that could be used to assign values to the normative parameters relevant to social discounting in welfare economics generally, and climate economics more specifically. First, I argue that in particular circumstances, there cannot be philosophical argumentation for normative questions; specifically, this occurs when the particular values being sought are both non-critical and from a quantitative range. Second, I argue that social preferences are insufficient if we take the problem to be normative and that proposals (...) for informed social preferences face significant challenges in implementation. Finally, I argue in favour of expert elicitation for experts in welfare economics, construed as those who understand the theoretical implications of adopting particular judgments. Those who understand the theoretical implications of adopting particular judgments will be better placed to develop coherent social plans while integrating relevant empirical data. (shrink)