Tax Deductible Spending, Environmental Policy, and the "Double Dividend" Hypothesis

A number of recent studies have shown that the general equilibrium welfare effects of externality-correcting policies depend importantly on pre-existing taxes in the economy, particularly those that distort the labor market. This paper extends the prior literature by allowing for consumption goods that are deductible from labor taxes. These "goods" represent medical insurance, other less tangible fringe benefits, mortgage interest, and so on. The initial tax system effectively subsidizes tax-favored consumption relative to other consumption, in addition to distorting the labor market. We find that incorporating tax-favored consumption may overturn key results from earlier studies. In particular, a revenue-neutral pollution tax (or auctioned pollution permits) can produce a substantial "double dividend" by reducing both pollution and the costs of the tax system. The second dividend arises because the welfare gain from using environmental tax revenues to cut labor taxes is much larger when labor taxes also distort the choice among consumption goods. Indeed (ignoring environmental benefits) the overall costs of a revenue-neutral pollution tax are negative in our benchmark simulations, at least for pollution reductions up to 17 percent, and possibly up to 42 percent. In addition, we show that the presence of tax-favored consumption may dramatically increase the efficiency gain from using (revenue-neutral) emissions taxes (or auctioned emissions permits) over grandfathered emissions permits.