Clearly, the historical increase in the air's CO2 content that has been experienced to date has vastly benefited mankind and enabled our numbers to grow considerably. In fact, the very existence of many of the people who read these words may well be attributed to that phenomenon. But what of the future? The population explosion of our species has not yet subsided; and there is real concern about our ability to feed the projected population of the world a mere fifty years hence.
Tilman et al. (2001) addressed this problem in an analysis of the global environmental impacts of agricultural expansion that may occur over the next half-century. Based on projected increases in population, and even accounting for expected concomitant advances in technological expertise, they concluded that the task of meeting the global food demand expected to exist in the year 2050 will likely exact a heavy environmental toll and produce great societal impacts.
What are the specific problems? Tilman and his colleagues report that "humans currently appropriate more than a third of the production of terrestrial ecosystems and about half of usable freshwaters," noting that this usurpation of natural resources will increase even more in the future. In terms of the amount of land devoted to agriculture, they calculate an 18% increase over the present by the year 2050; but because developed countries are expected to withdraw large areas of land from farming over the next fifty years, the net loss of natural ecosystems to cropland and pasture in developing countries will amount to about half of all potentially suitable remaining land, which would "represent the worldwide loss of natural ecosystems larger than the United States."
The scientists go on to say that this phenomenon "could lead to the loss of about a third of remaining tropical and temperate forests, savannas, and grasslands." What is more, in a worrisome reflection upon the consequences of these land-use changes for both plants and animals, they remind us that species extinction follows rapidly on the heels of habitat destruction. Finally, in another acknowledgement of just how serious the situation is, Tilman and his associates report that "even the best available technologies, fully deployed, cannot prevent many of the forecasted problems."
So what can possibly be done to avert this future food production shortfall and its devastating consequences that "even the best available technologies, fully deployed," cannot prevent? This is the question that was addressed by Idso and Idso (2000) in their treatise entitled Forecasting World Food Supplies: The Impact of the Rising Atmospheric CO2 Concentration; and it was their conclusion that -- after all that man can do -- the aerial fertilization effect of the increase in the air's CO2 content that is expected to occur by the year 2050 would be just barely sufficient, in the mean, to assure the agricultural productivity required to prevent mass starvation in many parts of the globe without usurping what little of the natural world would remain at that time.
In view of these observations, not only is the ongoing rise in the air's CO2 content essential for the future well-being of man, it is essential to the future well-being of the entire biosphere.
Idso, C.D. and Idso, K.E. 2000. Forecasting world food supplies: The impact of the rising atmospheric CO2 concentration. Technology 7S: 33-55.
Mayeux, H.S., Johnson, H.B., Polley, H.W. and Malone, S.R. 1997. Yield of wheat across a subambient carbon dioxide gradient. Global Change Biology 3: 269-278.
Tilman, D., Fargione, J., Wolff, B., D'Antonio, C., Dobson, A., Howarth, R., Schindler, D., Schlesinger, W.H., Simberloff, D. and Swackhamer, D. 2001. Forecasting agriculturally driven global environmental change. Science 292: 281-284.