Zusammenfassung:
This paper formalizes the geopolitical externality of climate policy and estimates its plausible magnitudes. Specifically, domestic reductions in fossil fuel demand depress global prices, thereby lowering export revenues for resource-rich autocracies - many of which allocate substantial resources to military spending. As a result, climate policy reduces geopolitical and security burdens on Western democracies, offering a potential "peace dividend" as a cobenefit. Exploiting the link between the European Union's oil consumption and the EU's costs of the Russian war in Ukraine as a case study, we highlight the relevance of this externality. We estimate that each euro spent on oil in the EU generates geopolitical costs of 0.37 [0.01 - 4.7] euros related to Russia's war on Ukraine. Based on our central estimate, a carbon price of 62 euros per ton of CO2 would be required to internalize these costs. Even under conservative assumptions, our analysis highlights that the geopolitical externality offers a compelling argument for strong unilateral efforts to reduce fossil fuel demand in the EU.