Notwithstanding great progress in scientific and economic understanding of climate change, it has proven difficult to forge international agreements because of free-riding, as seen in the defunct Kyoto Protocol. This study examines the club as a model for international climate policy. Based on economic theory and empirical modeling, it finds that without sanctions against non-participants there are no stable coalitions other than those with minimal abatement. By contrast, a regime with small trade penalties on non-participants, a Climate Club, can induce a large stable coalition with high levels of abatement.

This paper combines panel data on monthly mortality rates of US states and daily temperature variables for over a century (1900-2004) to explore the regional evolution of the temperature-mortality relationship and documents two key findings. First, the impact of extreme heat on mortality is notably smaller in states that more frequently experience extreme heat. Second, the difference in the heat-mortality relationship between hot and cold states declined over 1900-2004, though it persisted through 2004. Continuing differences in the mortality consequences of hot days suggests that health motivated adaptation to climate change may be slow and costly around the world.