Presents the paper "Tax Deductions, Environmental Policy, and the "Double Dividend" Hypothesis," written by Ian Parry and Antonio Bento in May 1999 for the World Bank. The authors find that incorporating tax-favored consumption in models of environmental tax swaps may overturn key results from earlier studies.

A rigorous and innovative approach for integrating environmental policies and fiscal reform for the U.S. economy. Energy utilization, especially from fossil fuels, creates hidden costs in the form of pollution and environmental damages. The costs are well documented but are hidden in the sense that they occur outside the market, are not reflected in market prices, and are not taken into account by energy users. Double Dividend presents a novel method for designing environmental taxes that correct market prices so that they reflect the true cost of energy. The resulting revenue can be used in reducing the burden of the overall tax system and improving the performance of the economy, creating the double dividend of the title. The authors simulate the impact of environmental taxes on the U.S. economy using their Intertemporal General Equilibrium Model (IGEM). This highly innovative model incorporates expectations about future prices and policies. The model is estimated econometrically from an extensive 50-year dataset to incorporate the heterogeneity of producers and consumers. This approach generates confidence intervals for the outcomes of changes in economic policies, a new feature for models used in analyzing energy and environmental policies. These outcomes include the welfare impacts on individual households, distinguished by demographic characteristics, and for society as a whole, decomposed between efficiency and equity.

In recent years there has been great interest in the possibility of substituting environmentally motivated or 'green' taxes for ordinary income taxes. Some have suggested that such revenue-neutral reforms might offer a 'double dividend:' not only (1) improve the environment but also (2) reduce certain costs of the tax system. This paper articulates different notions of 'double dividend' and examines the theoretical and empirical evidence for each. It also draws connections between the double dividend issue and principles of optimal environmetal taxation in a second-best setting. A weak double dividend claim is that returning tax revenues through cuts in distortionary taxes leads to cost savings relative to the case where revenues are returned lump sum. This claim is easily defended on theoretical grounds and (thankfully) receives wide support from numerical simulations. The stronger versions contend that revenue-neutral swaps of environmental taxes for ordinary distortionary taxes involve zero or negative gross costs. Analyses numerical results tend to cast doubt on the strong double dividend claim. Yet the theoretical case against the strong form is not air-tight, and numerical dividend claim is dividend claim is rejected (upheld) are related to the conditions where the second-best optimal environmental tax is less than (greater than) the marginal environmental damages. The difficulty of establishing a strong double dividend claim heightens the importance of attending to and evaluating the (environmental) benefits from environmental taxes.