The Political Economy of a Planetary Sunshade

Geoengineering proposals are increasingly acknowledged as possible responses to climate change because of the repeated failure of national decision makers to solve the collective action problem of allocating carbon emission reductions at the Conference of the Parties to the United Nations Framework Convention on Climate Change. Geoengineering is attractive, the possible moral hazard notwithstanding, because of differences in the economic effects of climate change across countries, which are organized as factions seeking to shift the burden of carbon reductions or to delay response. This article outlines the political economic advantages of a planetary sunshade to reduce the amount of sunlight reaching the Earth. Rather than adopt the more common game theoretic model to describe the relevant international relations, construction of the planetary sunshade is characterized as an auction in which a single spacefaring power completes construction of the megaproject as a global good, comparable to the willingness of the United States to provide the dollar as a global reserve currency, and then determines the average global temperature based upon financial or material contributions from other countries. The willingness to contribute is based upon calculations of preferred average global temperatures.