In the summer issue of Wild Earth, Earth First! co-founder Dave Foreman takes on the "cornucopians," meaning anyone who argues that economic growth is actually good for the planet's ecological health. Nearly every word of his article betrays a deep misunderstanding of economics.

For example, he conflates population growth with economic growth. To show how daffy the late economist Julian Simon was, Foreman cites Simon's 1994 comment, "We now have in our hands -- in our libraries really -- the technology to feed, clothe and supply energy to an ever-growing population for the next 7 billion years."

On the face of it, the claim appears absurd. And Foreman takes some pains to show how absurd it is by citing calculations made by former University of Colorado physicist Al Bartlett. First, Bartlett calculates that world population doubling every 43 years (which is the time it took at 1994 growth rates) would equal the weight of the entire universe in 6000 years. Next, to cut Simon "some slack," Bartlett kindly reduces the calculated growth rate, making it a million times smaller than the 1994 rate, which still reaches a mass greater than that of the universe before the end of 7 billion years.

The trouble is, Foreman and Bartlett are reflexively assuming exponential population growth. But in 2000, the United Nations dropped its medium world population projection for 2025 to 7.8 billion people. Only four years before, its projection had been 8.04 billion. According to many demographers, world population will likely top out at about 8.5 billion in 2040 or so and then begin to drop. Even Nature has published an article arguing that world population will probably never exceed 10 billion and in fact could be going down by the end of the century.

And why will it go down? Foreman cites Garrett Hardin's claim that "Exponential growth is kept under control by misery"; as evidence, Foreman points to "population decline in Russia today with its ruined economy and despair for the future." But while misery is undoubtedly a check on population, some of the lowest fertility rates -- below replacement, in fact -- are in such hellholes as Italy, France, Japan, the Netherlands, and Germany. Wealth, not poverty, appears to be the best contraceptive.

Foreman even defends Stanford entomologist Paul Ehrlich's simple-minded The Population Bomb. Ehrlich's 1968 book is infamous for its predictions that never came true, but Foreman claims the author "was only offering a variety of possible scenarios for the future," not "making hard predictions."

Re-read the book, Foreman. And make sure you're looking at the original edition: Ehrlich later made several unacknowledged changes that toned down his claims. In later editions, for example, there's no prediction that India couldn't "possibly feed two hundred million more people by 1980." Similarly, the 1968 edition claims, "I have yet to meet anyone familiar with the situation who thinks that India will be self-sufficient in food by 1971." In the 1971 edition, the passage is gone: Reality had contradicted it. (By the 1980s, India was actually exporting grain.)

For Foreman, though, Ehrlich basically got things right. "Famine has struck," he writes. "Remember Ethiopia? Remember Somalia? How about North Korea? In truth, between 1968 and 1996, 250 million people died from starvation. That is roughly equivalent to the population of the United States."

Again, Foreman is misleading people about what was actually being predicted. In 1968, Ehrlich was talking vast, global famines, not an accumulated number of deaths over many decades. As for Somalia, Ethiopia, and North Korea, those tragedies have precious little to do with Ehrlich's hypotheses about human overpopulation, and everything to do with civil breakdown and foul government policies.

Foreman misses another point as well. Environmentalists constantly assume that ecology and biology are in some sense more fundamental than economics, and therefore that they can pronounce competently on economic matters without reading so much as an elementary text on the subject. It is clear that biologists haven't bothered with economics since they appropriated Malthus' now two centuries old economics as the central metaphor for ecology in the 19th century. To them, people are not much more complicated than, say, the Kaibab Plateau deer chronicled by Aldo Leopold. Once their natural predators had been killed off, the deer's population grew dramatically until they ran out of forage, then died off in large numbers from starvation.

Quoting physicist Bartlett again, Foreman derides anti-Malthusians as flat-Earthers, on the grounds that only a flat Earth that extends forever downward "assures humans of an unlimited supply of all the mineral raw materials that will be needed." And so Foreman mocks writers like technology guru George Gilder, who wrote that we must overcome "the illusion that resources and capital are essentially things that can run out."

Bartlett and Foreman apparently believe that "resources" are a kind of hidden treasure. But a piece of copper ore is just a rock unless one has the knowledge to mine, melt, refine, alloy, mill, shape, and ship it. The Stone Age didn't end because humanity ran out of stones. Whether some physical quantity is a resource or not depends crucially on our knowledge about it. It took centuries for people to learn how to use sand to make glass, and now sand in the form of silicon chips fuels the information age. Was sand always a "resource" or did it become one when human ingenuity was applied to it?

Stanford economist Paul Romer distinguishes "things," like sand, from "ideas," like the techniques of glassmaking. The Earth is finite, as Foreman says, but humanity hasn't become better off just by using more and more resources. That's the strategy of the deer. People create resources by finding uses for what once seemed useless. In Romer's words, "Economic growth springs from better recipes, not just from more cooking." We make ourselves better off not by increasing the amount of stuff on planet Earth -- that is, of course, effectively fixed -- but by rearranging the stuff we have available so that it provides us with more of what we want. As we become cleverer about rearranging material, the more goods and services we can get from relatively less stuff.

And humanity has been spectacularly successful at rearranging the finite amount of stuff on Earth to provide more resources. In the past three decades, for example, food per capita in the poor countries has gone up by 25 per cent and is now cheaper and more abundant than it has ever been in history. This increase in food production was achieved largely through technology (better ideas), not by expanding cropland (things).

Even the Worldwatch Institute acknowledges, in its Vital Signs 2001 report, that "nonfuel commodities now fetch only about 46 percent as much as in the mid-1970s. Indeed, Worldwatch admits that "food and fertilizer prices are about one-fourth their 1974 peak." Even the price of crude oil, which has risen lately, "nevertheless remains at about half the zenith reached in 1980." In fact, overall non-fuel commodities cost only a third of what they did in 1900. As everyone knows, lower prices mean that things are becoming more abundant, not more scarce.

At the end of his screed, Foreman writes "those of us who warn of limits recognize Traven's Law: This is the real world, muchachos, and you are in it." But far from the "real world," Foreman remains lost in the abstract fog of environmentalist dogma -- a dogma that is based on long-outdated economic theory. We still face some serious ecological problems. But misdiagnosing their causes will not help us deal with them.