Al Gore’s An Inconvenient Truth has met its match: a devastating documentary recently shown on British television, which has now been viewed by millions of people on the Internet. Despite its flamboyant title, The Great Global Warming Swindle is based on sound science and interviews with real climate scientists, including me. An Inconvenient Truth, on the other hand, is mostly an emotional presentation from a single politician.

The scientific arguments presented in The Great Global Warming Swindle can be stated quite briefly:

1. There is no proof that the current warming is caused by the rise of greenhouse gases from human activity. Ice core records from the past 650,000 years show that temperature increases have preceded—not resulted from—increases in CO2 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. Dire predictions of future warming are based almost entirely on computer climate models, yet these models do not accurately understand the role or water vapor—and, in any case, water vapor is not within our control. Plus, computer models 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.

The best evidence supporting natural causes of temperature fluctuations are the changes in cloudiness, which correspond strongly with regular variations in solar activity. The current warming is likely part of a natural cycle of climate warming and cooling that’s 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 claim that the current warming is “unusual” using spurious analysis of tree rings and other proxy data. Advocates have tried to deny the existence of these historic climate swings and claim that the current warming is "unusual" by using spurious analysis of tree rings and other proxy data, resulting in the famous “hockey–stick” temperature graph. The hockey-stick graph has now been thoroughly discredited.

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

• Control of CO2 emissions, whether by rationing or 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 the sequestration of CO2 from smokestacks or even from the atmosphere

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

3. 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. Why do we assume that the present climate is the optimum? Surely, the chance of this must be vanishingly small, and the economic 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 wars? 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 squander our limited resources to fashionable issues, rather than concentrate on real problems. Just consider the scary predictions emanating from supposedly responsible world figures: the chief scientist of Great Britain 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 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.