OAKLAND, Calif. -- AL GORE’S MOVIE, An Inconvenient Truth, has met its match: a devastating documentary recently shown on British television, which has also been viewed by millions of people on the Internet. In spite of its flamboyant title, The Great Global Warming Swindle is based on sound science by recording the statements of real climate scientists, including me.

An Inconvenient Truth mainly records a politician. The scientific arguments in The Great Global Warming Swindle can be stated quite briefly:

There is no proof at all that the current warming is caused by the rise of greenhouse gases from human activities, such as the generation of energy from the burning of fossil fuels. Observations in polar ice cores show that temperature increases have preceded — not resulted from — increases in carbon dioxide, by hundreds of years, suggesting that the warming of the oceans is an important source of the rise in atmospheric CO². As the dominant greenhouse gas, water vapor is far, far more important than CO², yet not well handled by climate models, and, in any case, not within our control.

Greenhouse models also cannot account for the observed cooling of much of the past century (1940-75), nor for the observed patterns of warming — what we call the “fingerprints.” For example, the Antarctic is cooling while models predict warming. And where the models call for the middle atmosphere to warm faster than the surface, the observations show the exact opposite. But the best evidence we have supports natural causes — changes in cloudiness linked to regular variations in solar activity.

Thus the current warming is probably part of a natural cycle of climate warming and cooling that has been traced back almost a million years. It accounts for the Medieval Warm Period around 1100 A.D., when the Vikings settled Greenland and grew crops, and the Little Ice Age, from about 1400 to 1850 A.D., which brought severe winters and cold summers to Europe, with failed harvests, starvation, disease, and general misery.

Attempts have been made to assert that the current warming is “unusual”; a spurious analysis of tree rings and other proxy data tried to deny the existence of these historic climate swings. However, this result, that earth temperatures have been constant until recent decades, has now been thoroughly discredited.

If the cause of warming is mostly natural, then there is little we can do about it. We cannot influence the inconstant sun, the likely origin of most climate variability. None of the schemes of mitigation currently bandied about will do any good; they are all irrelevant, useless, and wildly expensive:

•Control of CO² emissions, whether by rationing or by elaborate cap-and-trade schemes.

•Uneconomic “alternative” energy, such as ethanol and the impractical “hydrogen economy.”

•Massive installations of wind turbines and solar collectors.

•Proposed projects for sequestration of CO² from smokestacks or even from the atmosphere.

Ironically, all of these schemes would be ineffective even if CO² were responsible for the observed warming trend, unless we could persuade leaders of every nation, including China, to cut fuel use by 80 percent!

Finally, no one can show that a warmer climate would produce negative impacts overall. The much-feared rise in sea levels does not seem to depend on short-term temperature changes, as the rate of sea-level increases has been steady since the last ice age, 10,000 years ago. In fact, many economists argue that the opposite is more likely — that warming produces a net benefit, that it increases incomes and standards of living. All agree that a colder climate would be bad.

So why would the present climate be the optimum? Surely, the chances for this must be vanishingly small, and the history of past climate warmings bear this out. But the main message of The Great Global Warming Swindle is much broader. Why should we devote our scarce resources to what is essentially a non-problem, and ignore the real problems the world faces: hunger, disease, denial of human rights — not to mention the threats of terrorism and nuclear war? And are we really prepared to deal with natural disasters; pandemics that can wipe out most of the human race, or even the impact of an asteroid, such as the one that wiped out the dinosaurs?

Yet politicians and the elites throughout much of the world prefer to toy with and devote our limited resources to fashionable issues, rather than concentrate on real ones. Just consider the scary predictions emanating from supposedly responsible world figures: the chief scientist of Britain’s Labor Party tells us that unless we insulate our houses and use more efficient light bulbs, the Antarctic will be the only habitable continent by 2100, with a few surviving breeding couples propagating the human race. Seriously!

I imagine that in the not-too-distant future, all of the hype will have died down, particularly if the climate should decide to cool — as it did during much of the past century; we should take note here that it has not warmed since 1998. Future generations will look back on the current madness and wonder what it was all about. They will have movies like An Inconvenient Truth and documentaries like The Great Global Warming Swindle to remind them.

S. Fred Singer is a professor emeritus of environmental sciences at the University of Virginia and research fellow at the Independent Institute, based in Oakland, Calif. ( www.independent.org). He served as the founding director of the U.S. Weather Satellite Service and was vice chairman of the U.S. National Advisory Committee on Oceans and Atmosphere. His most recent book is Unstoppable Global Warming: Every 1,500 Years.