One afternoon, in February 1997, Bjorn Lomborg was flicking through a copy of Wired magazine in a Los Angeles bookshop when he came upon an interview with the American economist Julian Simon. Back then, Lomborg was a self-described "left-wing Greenpeace activist": he accepted most of the orthodoxies of the environmental movement about climate change, the deterioration of the ozone layer, air pollution, deforestation, species extinction, overpopulation and the depletion of natural resources. Unless we altered our behaviour, he believed, we would soon be confronted with imminent environmental catastrophe. But here was Simon saying that much of our supposed knowledge about the environment was based on prejudice, preconceptions and poor statistics.
Lomborg was intrigued. On his return to Denmark, where he was associate professor of statistics at Arhus University, he gathered his brightest students into a study group. The intention was to destroy Simon's thesis through the rigorous application of statistics. "What we discovered changed my life for ever," Lomborg, now 37, told me when I met him in Copenhagen. "For much of what Simon said about the environment was true and much of what we as Greens believed was false - that, for instance, the air in the developed world is becoming less, not more, polluted. I realised that if I was wrong in what I believed about the environment, I was not the only one."
Lomborg contacted a Danish newspaper, the centre-left Politiken, and offered to write a series of articles. His aim was not "to discredit green activists so much as help them think more clearly about the issues at hand". They did not respond well. Eco-campaigners throughout Scandinavia denounced Lomborg as a fanatic and apologist for capitalist excess. A website, anti-lomborg.com, was set up to disparage him.
In 1998, Lomborg published a book, a statistically dense elaboration of his articles. In 2001, it was revised, substantially updated and republished by Cambridge University Press as The Skeptical Environmentalist, in which he argued that for much of the past 50 years humankind had experienced unprecedented improvement in almost every welfare indicator: we live longer and healthier lives, we are richer and more literate, we enjoy more liberties and freedoms, and world poverty and hunger are slowly declining. The "colossal sums" governments planned to spend in an attempt to reduce global warming would, he wrote, "be money ill spent". Above all, he said, liberal democratic capitalism was good for the environment, especially when compared to the old command economies of the former Soviet bloc. We were emphatically not killing our planet.
The Skeptical Environmentalist is perhaps the most important book about the environment since Rachel Carson's Silent Spring (1962) awakened the world to the dangers of unrestrained economic growth. It is certainly the most trenchant, and has led to the worldwide vilification of Lomborg. Scientific American published a 12-page special report with the sole intention of discrediting him. Nature magazine accused him of the environmental equivalent of Holocaust denial. Even E O Wilson, one of the great thinkers of our time, expressed public regret that a distinguished academic press should have published such a book.
Yet Lomborg has become something of a hero to all those who value bold, sceptical freethinking - even more so since the Danish Committee on Scientific Dishonesty accused him this year "of fabricating data, selectively and surreptitiously discarding unwanted results, of the deliberately misleading use of statistical methods, consciously distorted interpretation of the conclusions, plagiarisation of others' results or publications, and deliberate misrepresentation of others' results".
This was, in effect, academic criticism as character assassination. Lomborg has prepared a long written reply. He is supported by much of the Danish media - which consider the committee's decision an assault on scientific freedom of speech - by Cambridge University Press, and by commentators in Britain and the US. One portrayed him as a latter-day Galileo, under threat of being burnt at the stake of scientific unreason and eco-fundamentalism.
Bjorn Lomborg is an unlikely hate figure for the environmental movement. For a start, he is very green. He is openly gay and a vegetarian, he does not own a motor-car (a bicycle is his preferred mode of transport) and he neither drinks alcohol nor smokes. He still describes himself as "a liberal leftist with a strong concern for the environment". In person, he is candid and engaging. With his long blond fringe and fey manner, he could be mistaken for a member of a boy band - albeit one now rather exhausted after years on the pop circuit - rather than a career academic (he is at present director of the state-funded Environmental Assessment Institute in Copenhagen).
When I met him for dinner, at a mediocre pizzeria in central Copenhagen, he arrived, breathlessly, on his bicycle and was dressed - in clumpy white sneakers and a heavy red jumper - as casually as any of his students. At first, he seemed excessively camp and rather boyish; he confessed he chose the restaurant because he "just adores pizza and Coca-Cola, and the pizzas here are just so great". Later, he told me about how he had grown up in Alborg, in northern Jutland, as a "very academic teenager, clever in a slightly nerdy way, awkward, the kind of guy who would always be picked last for the football team".
Lomborg speaks good, idiomatic English with a pronounced American accent, which he picked up during a gap year at the University of Georgia. It was there that, as well as becoming a more open, adventurous spirit and accepting his sexuality, he had what he grandly describes as his political awakening. "I didn't have big academic aspirations at the time, and became very caught up in the peace movement," he says. "I was worried about nuclear weapons, I wanted to change the world and, once back home, I became heavily involved in the protests against Nato, and that kind of thing." After studying political science, he took a PhD in statistics and would have been "happy to have spent the rest of my career doing obscure work that was read by about 50 people" had he not that afternoon entered the bookshop in LA. That, at any rate, is how he tells it.
John Gray, a London School of Economics professor and regular NS contributor, argues that Lomborg "packages himself as an open-minded thinker, but what he's really selling is another version of the prevailing myth of progress. The message of his book is that humanity can have everything it wants so long as it adopts a market-based economic system and uses the best technologies. The clear implication is that there is no need to restrain human ambitions in order to protect the environment; it can look after itself. In effect, this is a recycled version of the technological utopianism that's always been popular in the US, and explains why he is so feted by big business."
Greens, many would say, have myths of their own: for example, that a human population of the current size can subsist mainly on forms of energy such as wind power, or that genetically modified organisms are bound to be bad for human health. "But these green myths," says Gray, "seem to me less harmful than Lomborg's progressive evangelism, which offers an hallucinatory vista of unending human advance when what's most needed from human beings at the moment is a bit of humility and self-restraint."
The green activist Rory Spowers, author of Rising Tides: a history of the environmental revolution (Canongate), says that when Lomborg's book appeared, he received "more airtime and column inches than any other journalist within the environmental debate, not only by the New York Times, the Economist and the Wall Street Journal, but by the BBC, too. Now, an increasingly well-informed public finds that all was not as it seemed; that by turning to Lomborg for an apparently objective and dispassionate account, one is only contributing to that expanding web of disinformation known as 'greenwash'. Rather than undermining the environmental movement, the most ambitious greenwash project to date has only ended up by supporting it."
One of the most persistent myths about Lomborg is that he is a polemicist, not a scientist; a career contrarian rather than a disinterested scholar - Spowers dismissed him as a "journalist". In truth, there is no such thing as unrivalled objectivity in science as there is in, say, arithmetic; scientific research is informed and constrained by the social and economic milieu in which it is undertaken, by the allegiances and prejudices, however unconscious, of the scientist himself, and by issues of funding.
Contrary to what is often said, The Skeptical Environmentalist was peer reviewed before publication. "I was made aware of Bj0rn Lomborg through an eminent American economist who knew that he was looking for an international publisher of his original Danish book," Lomborg's editor, Chris Harrison of CUP, told me. "When the English translation landed on my desk, I was myself very sceptical but I didn't think I should reject it without sending it out for review. I sent it out to professors in the UK and in America with expertise in climate change, biodiversity, environmental policy and economics. Rather to my surprise, all four recommended publication. Had it been my decision alone, I probably would have rejected it."
Harrison denies the eco-fundamentalists' claim that Lomborg is in the pay of corporate interests. Lomborg, he adds, "is not afraid of an argument and he certainly enjoys debate. During the editing process I argued a lot with him myself. One of the things I like about the book, and why it has done so well, is that it forces a reaction from the reader. One way or the other, we all have strong views and we're not too sure whom to trust."
The Lomborg controversy is in many ways an allegory of our human search for truth. We want to know what is best for ourselves and for our world, but we do not ultimately know who or which organisation to trust. Events in Iraq showed that we could hardly trust our own government. So whom can we trust when daily we are battered by bad news about the environment and confused by conflicting forecasts?
The environmental activists have nothing but contempt for Lomborg. Mark Lynas, the author of a forthcoming book on global warming, recounted in a recent issue of the Ecologist how he had thrown a pie in Lomborg's face during a bookshop reading in Oxford. "A basic sponge cake topped with two inches of spray-can cream . . . met its target with a satisfying splat." "Pieing" is the preferred method of attack by anarchists. It is, as Lynas points out, "intended as a relatively light-hearted way to bring pompous and powerful people down a peg". But can Lomborg really be accused of either power or pomposity? One should not forget that a pie was thrown in the face of the maverick Dutch politician Pim Fortuyn shortly before he was murdered by an animal rights activist. As the verbal attacks on Lomborg have become more vehement, so he has begun, certainly since the murder of Fortuyn, to worry about his safety and about whether there are people out there who find what he says intolerable.
Yet Lomborg remains committed to his war against eco-fundamentalism. He is an optimist, an unapologetic believer in progress. Western-style affluence, he believes, is important because it offers the possibility of "adaptive capacity" - the ability of humans to adapt to new challenges, such as the need to discover new sources of fuel, as and when they arise. The militancy of many of his detractors serves only to strengthen the conviction that he is right. "I was taught that if you have a good case, you should pound the case," he says. "If you have a bad case, you should pound the table. It seems to me that my opponents like nothing more than to pound the table. It's their way of avoiding the substance of my argument."
Lomborg is used to being recognised on the streets of Copenhagen, where he lives alone in a large apartment, and to continual criticism. "I don't want this to be my life," he says. "One day I hope to be able to move on from discussing the environment, maybe slip back into the shadows of academic life. But for now my mission remains to tell people that if they want to worry, they should worry about the right things. I think it's a shame when I hear a mother worrying about pesticides in food while forgetting to tell her son to wear a cycle helmet when he goes out on his bike. Understanding statistics is to understand the true nature of risk. The end of the world, I'm pleased to say, is not nigh."
"Hey, believe me," he says as we part. "It's not that bad."
The philosopher Daniel Dennett says that science is "the test of truth". The validity of that test depends on the rigorous application of scientific method. That is why the Danish committee tried to discredit Lomborg by first discrediting his method, his way of doing science. Because if his methods are wrong, then so are his findings, making him less a sceptical environmentalist than someone who is just plain wrong. But the eco-fundamentalists, as well as Lomborg, must be willing to accept the test of truth. It is after all they who demand far-reaching changes in western politics and lifestyle on the basis of data that remains at best uncertain and controversial. Lomborg's opponents should apply the same rigour that they demand from him, because somewhere between his scepticism and their dogmatism must lie the truth about the consequences to our planet of the human demand for progress.