Sharing the Cost of Global Warming *

For meteorological reasons, the distribution of climate‐change damage bears no relationship to the distribution of emissions across the globe. We argue in favor of offsetting this discrepancy. We propose a global insurance scheme of sorts, to be financed according to countries’ responsibilities in the matter. We analyze this horizontal equity problem using a responsibility/compensation framework, which we have adapted to a context of externalities. We characterize new versions of two well‐known cost‐sharing schemes.