Vegetational redistribution in Arizona and New Mexico in response to a doubling of the atmospheric CO/sub 2/ concentration

Abstract

In this report, we have attempted to present a reasonable first-order estimate of how the natural vegetation zones of Arizona and New Mexico may change in response to a doubling of the Earth's atmospheric CO/sub 2/ content. This analysis is based upon the weighty evidence that such a change in CO/sub 2/ concentration will have little effect on surface air temperature but a profound effect on plant water use efficiency, causing it to essentially double. The results should be viewed in the context of essentially united scientific thought relative to the projection that the Earth's atmospheric CO/sub 2/ content will indeed reach a doubled value of 600 ppm sometime in the next century, perhaps even as early as AD 2025. Also, it should be remembered that a quadrupling of the atmospheric CO/sub 2/ is the minimal ultimate concentration which is predicted to occur, and that the most recent studies of CO/sub 2/ effects on plant water use efficiency show that parameter to increase linearly all the way to such quadrupled CO/sub 2/ concentrations. Thus, what we have presented here may well be a very conservative estimate of what will eventually occur.