Curtis M Bell, Patrick W Keys 

Climate change and unabated greenhouse gas emissions are increasing the possibility that the world will turn to climate intervention to curb ever-increasing global temperatures. To date, most work on this topic has imagined that an international organization like the United Nations or an international coalition of states will synchronize their efforts to deploy climate intervention at ideal latitudes to maximize global effect. Nearly all climate model simulations run-to-date have assumed this. Thus, our understanding of the science of climate intervention is largely based on an ideal of perfect geopolitical coordination. However, geopolitical uncertainties make this scenario unlikely and the costs of climate intervention are sufficiently low that many states could comfortably finance a climate intervention program that could have global consequences. This paper uses game theory to elucidate the conditions that might make a state more or less likely to begin unilateral climate intervention (UCI). We solve this game for several specific scientific, economic, and climatological conditions that change the likelihood of a government starting its own climate intervention program without the participation of the broader international community. Specifically, we demonstrate that the plausibility of UCI is linked to our scientific understanding of three key elements: (1) the effectiveness of climate intervention strategies, (2) the sensitivity of specific governments to punishment by other states, and (3) satisfaction with climate and weather in the present. We conclude by discussing how this formal game theory model informs the design of future earth system model simulations of UCI, international agreements related to climate intervention, and the development of solar climate intervention technologies.