Dominic Lawson: The debate on climate change is far too important to be shut down by the scientists

As the history of malaria in Africa shows, those who appear most passionate can be most dangerous

For the past 35 years a number of well-funded lobbying organisations have spread lies that have caused the deaths of countless millions of Africans, mostly children. Last week the World Health Organisation finally shook off the malign grip exercised by their campaign of misinformation: the new head of the WHO's anti-malarial programme, Arata Kochi, declared that the organisation would promote the use of indoor spraying with DDT, the insecticide which had wiped out malaria in the developed world, but which was banned before sub-Saharan Africa could benefit in the same way.

It was largely the pressure exercised by well-organised multinational lobbyists such as Greenpeace that persuaded the governments of the United States and Europe to refuse to sanction the use of DDT to combat the scourge of malaria in Africa, where about a million people a year die of the disease - entirely avoidably. There had been some evidence that intensive crop spraying with DDT in the 1960s had caused a drop of about 10 per cent in the thickness of the eggshells of some local breeds of birds. And that was it. The environmentalist lobby groups attempted, rather successfully, to spread the myth that the insecticide, which is no more carcinogenic than coffee, could cause cancer.

As a result, the EU threatened to ban food imports from African countries which had the temerity to advocate DDT in the battle to save children from a disease more deadly than AIDS. In effect, the West had put its own neurosis over trace chemicals in food, and the life-cycle of the American bald-headed eagle, over the lives and welfare of the entire African continent. It was a selfishness that rivalled the worst excesses of the colonial era, but justified with a sanctimony and self-righteousness which even the Victorian imperialists never matched.

Perversely, it was European and American "Big Pharma" which benefited most from the environmentalists' campaign against DDT. These companies earned hundreds of millions from the sale of drugs such as chloroquine, which have proven entirely ineffective in stamping out malaria. The only plant in the world now producing DDT is Indian-owned--and that has stayed open in defiance of a strident Greenpeace campaign to close it down.

Last week Mr Kochi, who worked for 30 years in the effort to stamp out TB, implored the green lobby: "I am here to ask you, please help save African babies as you are helping to save the environment. African babies do not have a powerful movement to champion their well-being."

The only response of the green lobby groups was an embarrassed silence - at least I hope that it was shame which lay behind their refusal either to endorse or condemn Mr Kochi.

I could have predicted this mute response. Five months ago I wrote a piece on this page describing the horrific consequences for sub-Saharan Africa that resulted from the use of grossly inferior antimalarial products, following the DDT ban. Apart from one reader who described my article as "mindless" and compared it with evolution-denial, there was no feedback whatsoever. The green lobby groups I criticised clearly wanted, in the modern jargon, to "close the argument down."

The argument they now want to close down is that over the causes and effects of global warming. As part of the campaign to promote a book by the leading environmentalist writer George Monbiot, the Royal Society has leaked a letter it wrote to ExxonMobil, demanding to know why the oil company had not cut its $3m funding to lobby groups which questioned the conventional scientific view of climate change.

It is idle to deny that ExxonMobil has a commercial interest in selling as much oil as it can, and therefore would welcome the views of those who argue that the role of man-made carbon emissions in global warming, or the extent of that warming, is exaggerated. But these lobby groups, such as the American Competitiveness Institute - whose chairman was treated by Jeremy Paxman on Wednesday's Newsnight as if he were some sort of war criminal - are not-for-profit bodies just like Greenpeace; and just like Greenpeace they have a passionate belief that they can help to make the world a better place.

Organisations such as The American Competitiveness Institute, or the London-based International Policy Network believe that humankind benefits most from free markets and minimal state interference in the economic decision-making of companies and individuals.

They also, it is fair to say, suspect that the global environmental movement is now the political home of those who were so comprehensively discredited when the Berlin Wall came down and it became clear to all just how much economic and moral poverty had been caused by the outlawing of profit. Even if you don't share that outlook, it ought not to be difficult to recognise that such lobby groups are no less passionately dedicated to the public good than others, such as Greenpeace, which have a wildly different agenda.

The Royal Society, it is true, has chastised Greenpeace in the past. Three years ago it pointed out that genetically modified food was no more harmful to humans than non-GM products, and denounced Greenpeace for "throwing up a smokescreen of unfounded claims about the threats to human health". On the other hand, I do not recall The Royal Society demanding that people stop donating money to Greenpeace.

If you read the actual letter from Mr Bob Ward, the Royal Society's senior PR man to his opposite number in Exxon's UK office, it is immediately clear that his main complaint is with the statements made about climate change in the company's annual review. And what is the statement which has so enraged Mr Ward? It is this: "Gaps in the scientific basis for theoretical climate models and the interplay of significant natural variability make it very difficult to determine objectively the extent to which the recent climate change might be the result of human actions."

At the risk of receiving a declaration of academic anathema from The Royal Society, I'd argue that this is no more than a turgid statement of the obvious: models of climate change are fantastically complicated, involving an almost infinite number of variables. Anyone who says he can determine objectively the precise role of human actions in climate change is either a charlatan or a megalomaniac.

Above all, there is no scientific merit in closing down the debate over climate change, particularly when the stakes are so high. As the terrible recent history of malaria in Africa shows, those who appear the most passionate can be the most dangerous.

d.lawson@independent.co.uk