To help ease future environmental damage, an environmental tax that increases over time should be adopted now, even in the apparent absence of pollution damage, according to a UC Davis economist who has been researching an optimal economic policy to deal with the problem. Underlying some of today's most pressing environmental problems are various forms of pollution that have accumulated over a long period of time, both from the exploitation and consumption of natural resources, says Y. Hossein Farzin, assistant professor of agricultural and resource economics at UC Davis. His research, recently published in the Journal of Public Economics, shows that even though there may be little environmental damage caused by various forms of pollutants now, the optimal economic policy requires abatement to begin immediately. If undertaken now to address the problem of air pollution, Farzin's model estimates that the required environmental tax would begin at as low as $6.54 per ton of carbon, which is equivalent to a tax of $0.73 on each barrel of oil consumed. The required tax then would rise at two percent a year for the next 122 years and thereafter remain at $75 per ton of carbon emitted. Farzin argues that these carbon taxes are very modest insurance premiums on environmental damage that is likely to occur.