Green ground revisited

Paul Ehrlich is an old hand on the apocalypse circuit. Not a charlatan by any means, but with a history of making doom-laden predictions that never quite come true. This creates problems for him in his latest work, Betrayal of Science and Reason: How Anti-Environmental Rhetoric Threatens Our Future, written with his wife, Anne. For one thing, it leaves them open to a counter-charge on the lines that their work reveals "how environmental rhetoric betrays science and reason".

First, his record. In the late 1960s, as a young ecologist specialising in butterfly demographics, Ehrlich noticed how their numbers tended to go from boom to spectacular bust. Under the right conditions, butterflies would breed so fast they would demolish all types of plant leaves they had evolved to eat and become extinct. He hypothesised that this might be happening to humans as well. And being a populist he turned this into confident prediction.

In 1968 - with world economic and population growth rates both approaching a peak - he wrote The Population Bomb, an influential polemic that offered three possible demographic futures for the human race. In the first, a billion people would starve to death between 1973 and 1983. In the second, rampant disease would halt population growth by the early 1980s. In the third, the Pope would throw his weight behind a global birth-control campaign and the billionth death from starvation would be delayed until about 1990.

He wrote: "The battle to feed all of humanity is overI Nothing could be more misleading to our children than our present affluent society. They will inherit a totally different world, a world in which the standards, politics and economics of the past are dead." Well, we are still waiting. World population growth rates are now falling fast. By and large, we are still feeding the world's population.

Why did he get his science wrong? The start of The Population Bomb hinted that a late-night taxi ride through Delhi had a lot to do with it: "The streets seemed alive with people. People eating, washing, sleeping, visiting, arguing and screaming. People thrusting their hands through the taxi window beggingI People, people, people, peopleI All three of us were, frankly, frightened."

Perhaps it reminded him of a swarm of butterflies, but John Caldwell, an eminent Australian demographer, acidly remarked later that Ehrlich "did not see population explosion, for Delhi's birth rate is relatively low. He probably saw fewer people than one would see with pleasure in New York, London or ParisI What he did see was poor non-Europeans."

I mention this because the Ehrlichs, in their latest book, have taken it on themselves to defend Paul's original claims and to debunk some myths of the environmental contrarians, part of what they call the "brownlash".

Bravely, in one chapter, they tackle "fables about population and food". They first settle on rebutting the usual suspects in the anti-environmental cause. First is the claim of that guru among optimists, Julian Simon, who says that we have the technology to feed "an ever-growing population for the next seven billion years". The Ehrlichs do some back-of-the-envelope calculations about population growth to demonstrate that current growth rates cannot continue, and conclude "such is the power of exponential growth. Simon's statement is nonsense".

Now Simon, like Ehrlich, is given to hyperbole. Seven billion years is a long time. But what is revealing is Ehrlich's apparent assumption that, barring some Malthusian disaster, we can expect continued exponential population growth. And it just is not so. The average woman in the world today has fewer than three children, compared with the five her grandmother had. The population growth rate is falling fast, and some believe the absolute world population could have stabilised, and even be falling, within 50 years.

To the charge that the world is not overpopulated today, the Ehrlichs use a tank teeming with guppy fish as a model. They did not do so well. Then the Ehrlichs show that we humans are degrading our environment, as judged by indexes such as soil erosion. They assert that we have exceeded the "carrying capacity" of the land to support us. But they do not demonstrate this. Our soils may be "degraded" by their definition, but with advancing agricultural technology we have grown more and fed more from those soils. The notion of carrying capacity is dissolving before our eyes.

This is not a counsel for complacency, but for "science and reason". The Ehrlichs are constantly heading off at tangents while claiming rigour for themselves. For instance, attacking the "myth" that "enviros hate people", they launch a spirited but purposeless assault on the Pope for refusing to accept immigrants, or even refugees, into Vatican City.

Finally, the Ehrlichs defend Paul's 1968 claim that "the battle to feed all of humanity is overI" Sure, we have not had the spectacular famines that he predicted, they say. But "some 250 million people have perished for lack of food since those words were written". This claim is not sourced. Presumably it is based on some calculation of higher death rates from the widespread inadequate diets in poor countries.

But there is ample evidence today that both the quality and quantity of food produced round the world today, as well as its distribution, is dependent on market forces rather than the "limits to growth" so much discussed a generation ago. In other words, hunger is an economic and political issue more than a technical or ecological one.

Finally, in a spectacularly circular argument that really should be banned from books attacking the "betrayal of reason", the Ehrlichs attest that the famines predicted in The Population Bomb were prevented by the world community "partly because of The Population Bomb and similar warnings". In other words, I am right because I was wrong. Or should that be the other way round?

All of this is a pity. For the anti-environmental crusaders do need a strong, robust critique of what they say. The truth is that they have made much of the running in the intellectual debate about environmental issues in the past decade or so - ever since Simon raised the banner with his breath-taking polemic The Ultimate Resource in 1981. Their critiques have seriously undermined some of the tenets, or at any rate some of the sloppy thinking, behind many environmental nostrums. From global warming to desertification, species extinction to toxicology, they have scored real hits.

And environmentalists have been uncertain how to respond. First they ignored them. More recently they have indulged in elaborate conspiracy theories about their critics. These conspiracies were often true, but rather beside the point in intellectual terms. (Of course, some of the guys took industry money to do their research and publish their polemics. So what? They are only tainted in the way that researchers who take Greenpeace money, say, are tainted. The only test has to be whether their claims stand up.) What has been rather missing is some rigorous revisionist thinking on the part of environmentalists themselves. They need to test their ideas rather more thoroughly. Which ideas, forged with so much endeavour in the 30 or so years since Rachel Carson's Silent Spring, have stood the test of time? There is too much green dogma - ideological baggage - that should have been thrown overboard, the better to sustain what is good.

Why lumber yourself with crazy nostrums about the "carrying capacity" of the land and outdated ecological theories of desertification when it slows you down in the pursuit of action on issues with a more robust scientific basis, such as the build-up of greenhouse gases in the atmosphere? The apocalypse may have been postponed, but that does not mean there are not serious environmental issues to be tackled.

Environmental Management is a less popular and populist work. The average word and average sentence both appear to be about twice as long as in the Ehrlichs' polemic. But it could hold some lessons for the Californian pair. Its mission is to offer "new directions for the 21st century" and it "focuses on the quest for predictability in the face of uncertainty".

The authors, both from King's College, London, offer some useful signposts for revisionist environmental thinking. They point out, for instance, that more intense use of environmental resources may not cause a Malthusian crash, but certainly causes an "inexorable increase in uncertainty". And they look systematically at the potential roles of political, economic and technological change in altering that uncertainty.

Some of this may be heavy going for a casual reader, but for students of environmental management it does its job well. The analysis is cool and dispassionate. And it is peppered with up-to-date and pointed examples: from Greenpeace's tussle with Shell over the dumping of the Brent Spar oil rig to the battles between logging companies and Penan tribesmen in Borneo.

Interestingly, neither author claims his prime expertise inenvironmental sciences per se. Both are geographers: one with a bent for archaeology and anthropology, the other for political sciences. The lesson may be that ecology is too important, and too interesting, to be left to ecologists.

Fred Pearce is environmentconsultant, New Scientist.