Climate change, fossil fuel prices and depletion: The rationale for a falling export tax

This paper examines how world prices affect depletion of exhaustible fossil fuels for export and the role of an export revenue tax in curbing depletion. Both effects are studied for a small open economy affected by climate change. We find that setting an export revenue tax rate to fall over time at the marginal social cost of depletion due to lower productivity from climate change encourages a resource exporter to leave an optimal stock in the ground – unextracted and unburnable. Growing prices during the past decade similarly curb depletion. Falling prices bring forward extraction. Because production is independent of consumption, the marginal social cost is independent of utility parameters which are difficult to estimate. Slowing fossil fuel extraction and the effective export of emissions is a contemporary challenge for climate policy. Our findings identify both why an export revenue tax should decline over time and an estimable target rate of decline to help meet this challenge amid changing world prices.