Equity in climate-economy scenarios: the importance of subnational income distribution

It is widely accepted that climate change raises equity considerations, and this has been addressed in various explicit and implicit ways in scenario-based climate and climate-policy research. In this paper I look in particular at the IPCC's well-known 'Special Report on Emissions Scenarios', in which equity is primarily quantified as the distribution of income between countries, and highlight the need for more explicit treatment of equity both within and across national borders. I apply an existing method for modeling subnational income distributions and show that this affects the results of welfare calculations of the type used in economic analyses of climate policy. Additionally, I suggest ways in which this kind of equity analysis could be applied to questions that address broader considerations of climate policy and development, such as burden sharing in the allocation of obligations, and conclude with remarks that frame the scenario development process in the context of what I call 'the contested storyline of the present'.