Taxing Car-produced Carbon Dioxide Emissions: Matching the Cure to the Disease

The amount of carbon dioxide (CO2) emissions produced by cars is a linear (albeit fuel specific) function of the amount of fuel consumed. Because CO2 emissions generate social costs, through their effect on climate change, which escape the price mechanism, a tax on CO2 is indicated. An ideal tax would alter the consumer prices so that they match the marginal social costs. This setting thus calls for a specific tax on fuel equal to the value of externality resulting from the combustion of a unit of fuel. Since such tax scheme is readily available, we study to what extent the existing CO2 tax policies make use of it. We find that they do only to a limited extent. Thus our policy prescription is to drop existing CO2 taxes and use the existing fuel taxes to adjust fuel prices so that they match the marginal social costs related to burning of fuel.