This is the most recent and perhaps most dramatic in a long series statements by prominent politicians about the putative threat of man-made global warming. On what did Tony Blair base his alarming view? New scientific insights? Or on an unshakable secular faith, which seems to fill the vacuum left by the demise of traditional religion? I surmise the latter. Because in the field of science there seems to be some shift towards a more sober look at the climate issue, witness the numerous studies which appear in peer-reviewed journals, which are either explicitly critical of, or implicitly inconsistent with the man-made global warming hypothesis.

The ongoing discussion on the "hockey stick" graph -- a reconstruction of temperatures in the Northern Hemisphere between the years 1000 and 2000 -- offers a case in point. This debate entered a new phase when Steve McIntyre, one of the foremost hockey-stick critics, who had long been ignored, if not ostracized, by the global warming community, was officially invited by the National Research Council of The National Academies of the United States to participate in a special committee. This committee was requested to summarize the current scientific information on the temperature record over the past two millennia, describe the proxy records that have been used to reconstruct pre-instrumental climatic conditions, assess the methods employed to combine multiple proxy data over large spatial scales, evaluate the overall accuracy and precision of such reconstructions, and explain how central the debate over the paleoclimate temperature record is to the state of scientific knowledge on global climate change. It was exactly the mandate which Steve McIntyre had been advocating all along.

Politicians regard the studies by the Intergovernmental Panel on Climate Change (IPCC) as the ultimate climate bible. Unfortunately, they do not read the comprehensive reports which form the basis of the whole exercise. They only read -- if at all -- the alarmist passages in the "Summary for Policy-maker", which have been skewed through an elaborate and sophisticated process of spin-doctoring. Details of this practice have recently been revealed by the French climatologist Marcel Leroux in his book, Global Warming - Myth or Reality? The Erring Ways of Climatology.

Disapproving these practices, various renowned scientists have distanced themselves from the IPCC. In the US, Chris Landsea, a hurricane expert, is one example. In the Netherlands, Henk Tennekes, former director of the research department of the Royal Meteorological Institute, and Hans Oerlemans, glaciologist and laureate of the prestigious Spinoza Award, have done the same.

Political leaders assume that climate science is sufficiently advanced to legitimize all kinds of draconian measures which have a profound impact on our society and economy -- measures which, moreover, encroach upon the liberty of the individual citizen. But if we take a closer look, this appears not to be the case. Contrary what is often argued, there is no consensus among scientists on the man-made global warming hypothesis.

Ironically, just as global warming scare-mongering reaches new heights, the global cooling hypothesis is making a come back. It should be recalled that the frightening images of imminent global warming disaster are of fairly recent vintage. After all, in the 1960s and 1970s various prominent climatologists held the view that it was not global warming that formed a mortal threat to humanity but global cooling.

Recently the astronomer Khabibullo Abdusamatov of the Pulkovo Astronomic Observatory in St. Petersburg declared that the Earth will experience a "mini Ice Age" in the middle of this century, caused by low solar activity. Temperatures will begin falling six or seven years from now, when global warming caused by increased solar activity in the 20th century reaches its peak. The coldest period will occur 15 to 20 years after a major solar output decline between 2035 and 2045, Abdusamatov said. This view is shared by the Belgian astronomer, Dirk Callebaut, who expects a "grand minimum" in the middle of this century, just like the Maunder Minimum (1650-1700), a period during which the Thames, the Seine and the Dutch canals were frozen in winter.

If these astronomers are right, the hundreds of billions of dollars the world will spend every year on the fight against global warming will have gone down the drain. But, of course, we are not sure of imminent global cooling. On the other hand, we are not sure whether there will be catastrophic global warming either.

What to do in the face of this uncertainty? The earlier-mentioned climatologist, Henk Tennekes, recently argued in an interview in the most prominent Dutch weekly, Elsevier: "We only understand 10 percent of the climate issue. That is not enough to wreck the world economy with Kyoto-like measures."

Amen.

Hans Labohm, co-author of Man-Made Global Warming: Unravelling a Dogma, recently became an expert reviewer for the United Nations Intergovernmental Panel on Climate Change

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