In recent times, the state of climate earth is of concern to many people. Accounts of global warming, ozone holes, floods, droughts, and year-to-year variability of the weather in the decade of the SO's appear in popular media. Much attention has been focused on the possibility of growing crops in a changing environment (Rosenberg, 1981). Actual measurements of changing concentrations of trace gases in the atmosphere give credence to some of these fears (Schneider, 1990). Their actual impact on our weather is, however, controversial (Schneider, 1990). Computer models describing the atmosphere responding to these changes in gaseous composition predict a warmer earth with expected changes in precipitation. Some locations may experience weather patterns more favorable for crop production with others being exposed to more harsh weather (Manabe and Wetherald, 1986). There are great uncertainties with these models (Schneider, 1989), but most predict a warmer earth in future years.