Environmental Tax Reform with Vertical Tax Externalities

The paper studies a regional environmental tax reform in a federal state. A region unilaterally improves the environmental quality by increasing its energy taxes. The regional government recycles the excess tax revenues by lowering either pre-existing distorting labor or capital taxes. This regional tax reform causes a vertical tax externality in the federal budget. We show how the nature of this externality depends on the environmental goal, the tax-recycling scenario, the initial local and federal tax shares, and the relative importance of the reforming region in the federal state. Simulations illustrate the effects for Belgium and US.