Clearly, the hearts of these gentlemen are in the right place; but without a knowledge of all the pertinent facts, their prescription for the planet could well be way off base and, in fact, prove our downfall ... and that of the rest of the biosphere as well.

It thus behooves us to seriously consider the findings of Tilman et al. (2001), reported just four days later in the pages of Science, which Leo and Gergen had obviously not the advantage of seeing when they composed their essays.  In an analysis of the global environmental impacts of agricultural expansion that will likely occur over the next 50 years, which was based upon projected increases in population and concomitant advances in technological expertise, the group of ten respected researchers concluded that the task of meeting the doubled global food demand they calculated to exist in the year 2050 will likely exact an environmental toll that "may rival climate change in environmental and societal impacts."

What are the specific problems?  For starters, Tilman and his colleagues note that "humans currently appropriate more than a third of the production of terrestrial ecosystems and about half of usable freshwaters, have doubled terrestrial nitrogen supply and phosphorus liberation, have manufactured and released globally significant quantities of pesticides, and have initiated a major extinction event."  Now, think of doubling those figures.  In fact, do even more; for the scientists calculate global nitrogen fertilization and pesticide production will likely rise by a factor of 2.7 by the year 2050.

In terms of land devoted to agriculture, they calculate a less ominous 18% increase over the present.  However, because developed countries are expected to withdraw large areas of land from farming over the next 50 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, in the words of Tilman et al., "represent the worldwide loss of natural ecosystems larger than the United States."  Looking at it another way, the scientists say this phenomenon "could lead to the loss of about a third of remaining tropical and temperate forests, savannas, and grasslands."  And in a worrisome reflection upon the consequences of these changes in land use for global biodiversity, they note that "species extinction is an irreversible impact of habitat destruction."

These findings should come as no surprise to readers of CO2 Science Magazine, for we have dealt with them editorially many times (1 Oct 1999, 1 Feb 2000, 15 Nov 2000,
21 Feb 2001).  Hence, we are in full agreement with Tilman et al. when they say "an environmentally sustainable revolution, a greener revolution, is needed."  In fact, something far above humanity's normal ability to devise and execute will be required to avert the impending catastrophe; for as Tilman and his associates rightly conclude, "even the best available technologies, fully deployed, cannot prevent many of the forecasted problems."

Here, then, is the real and truly inescapable problem facing the world and every living thing therein: where will we find the food and water needed to sustain our growing populations?  We are going to need much more of both of these precious commodities if we are ever going to make it through even the first half of the current century without self-destructing and taking most of the rest of the biosphere with us.  So we ask Mr. Leo and Mr. Gergen the very same questions they posed in their essays.  Do you "care about saving the planet" and doing those things that will not "darken the prospects for mankind"?

If you were sincere in your writing, and we believe you were, you will carefully consider a fact that is hardly ever mentioned in the international debate over anthropogenic CO2 emissions, and that is, that if there is any one thing that is known about carbon dioxide and global change with any certainty, it is that more CO2 in the air substantially enhances the growth of plants and the efficiency with which they utilize water.  Doubling the atmosphere's CO2 concentration, for example, typically increases crop productivity by 30 to 40%, while it increases plant water use efficiency even more, making it possible to produce considerably greater quantities of food with little to no increase in the amount of water used.  And in natural ecosystems, where water and other resources are often limiting, the positive effects of atmospheric CO2 enrichment can be even larger.

The enormity of the environmental problems we will surely face in trying to feed the world of tomorrow -- including our children and grandchildren and all the rest of the biosphere -- demands that we ask ourselves if we are ready to "risk the environment,"
as Mr. Gergen puts it, by using up nearly every bit of land and water on the face of the globe to meet caloric and nutritional needs, while polluting the rest of the planet and leaving next to nothing of value for nature, or if we will stubbornly take an "unnatural stand," as Mr. Leo describes it, and not allow the ongoing rise in the air's CO2 concentration to continue to bring about the only "environmentally sustainable revolution," to borrow an appropriate phrase from Tilman and company, that can go above and beyond what man's technological genius has the capacity to do and provide the extra productivity and efficiency edge the biosphere will surely need to meet the food security challenges of the coming half-century.

Industrialized society's "exhalations" of carbon dioxide are truly a godsend; for if we will let them, they can be the basis of Tilman et al.'s "greener revolution."  It's as natural as breathing; and for vegetation, that's exactly what it is.  Through the pores in their leaves, earth's plants breathe in the CO2 humanity releases to the atmosphere and it becomes the basic building block of everything they produce.  Ask your children about the process.  They learn it in grade school.  Plant's love CO2.  It's good for them.  And what's good for plants is good for everything else, humankind included.

In the end, however much we may try to ignore these facts, we cannot deny that we possess this knowledge.  And we now possess the additional knowledge that we desperately need what more CO2 can do for us, that it's absolutely essential, in fact, to avert a catastrophic breakdown of the biosphere over the next half-century, as we reported for the first time last year in Technology (Idso and Idso, 2000) -- see our Journal Review Will There Be Enough Food? -- and as Tilman et al. have now confirmed in Science.  And having this knowledge, we are morally obligated to act upon it.

Mr. Gergen says "strong leaders must summon us to the mountaintop."  He is right.  But we must know what mountain to climb, and that's where a knowledge of the pertinent facts becomes so important; for if we cannot see the truth, as the proverb rightly says, "where there is no vision, the people perish."  And if we turn our backs on carbon dioxide, which could truly be a savior for the planet, and crucify CO2 upon the cross of a counterfeit and misguided environmentalism, the people of the earth will do just that, they will perish, and not many years hence.

References
Idso, C.D. and Idso, K.E.  2000.  Forecasting world food supplies: The impact of the rising atmospheric CO2 concentration.  Technology 7S: 33-55.

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.