The global-warming documentary “An Inconvenient Truth” supposedly raises the curtain on the new Al Gore. And it does, in the sense that it’s not possible to have a nearly two-hour feature film devoted to lionizing you and your views without sprucing up your image. If nothing else, Gore’s dogged devotion to his cause – raising the alarm on global warming – is admirable.

But the Al Gore of “An Inconvenient Truth,” which is built around his PowerPoint presentation on the topic, isn’t really that new. There is the same earnestness. The same dire comparisons – he likens global warming to the threat from Nazi Germany and Islamic terrorists. The same nearly religious fervor. Gore has a gnostic’s faith that he gained special insight into the most important force in the universe when a college professor of his warned of rising C02 levels in the atmosphere decades ago.

Thus, his movie has about as much nuance as “Basic Instinct II.” It plays by the rules set by Michael Moore, which established that no left-wing political documentary can hope for success unless it is dishonest, or at the very least, extremely tendentious. Gore scores his most compelling points on behalf of his inconvenient truth by leaving out inconvenient facts.

His account of melting glaciers causing increased sea levels will be enough to prompt some people to begin to plan their evacuations of New York City, San Francisco and most of Florida right now. Gore even raises the prospect of a total melt-off of the Greenland ice sheet, causing a change in ocean currents that could bring a new ice age to Europe in a decade – a scenario ripped from the script of the ridiculous global-warming-cum-ice-age film “The Day After Tomorrow.”

For someone who is such a self-professed stickler for science, Gore leaves out all the complications in the glacier picture, as Jason Lee Steorts argues in the latest National Review. The world’s two largest ice sheets cover Greenland and Antarctica. The Antarctic Peninsula has indeed been melting, but it constitutes only 2 percent of Antarctica’s total area. A 2002 study in Nature found that two-thirds of the continent actually got colder from 1966 to 2000. A 2005 study published in Science looked at about 70 percent of Antarctica’s surface area and reported that the East Antarctic ice sheet had gained – yes, gained – 45 billion tons of ice annually between 1992 and 2003.

A more recent Science article argued that Antarctica has been losing ice over the past three years. But Steorts notes, “2002 was a high-watermark for Antarctic ice, so it’s not too surprising to see some decline since then.”

In Greenland, warmer temperatures are also causing the ice to melt at the edges, but the ice sheet is building up in the interior. A study in Science showed that the ice sheet had gained 5.4 centimeters of elevation annually between 1992 and 2003. If that increase is taken into account, the loss of ice in Greenland becomes too small to terrify anyone.

A central conceit of Gore’s film is that C02 is basically the only important driver of climate change. It’s not so. Climate is astonishingly complex. Greenland’s rising temperature might be mostly the result of a pattern of changes in the oceans’ surface temperature known as the Atlantic Multidecadal Oscillation. Greenland experienced just as much warming between 1920 and 1930 as it has in the past 10 years – except the warming 80 years ago happened at a faster rate. Since CO2 wasn’t a major factor then, this datum steps on Gore’s message and doesn’t make his PowerPoint presentation.

Global warming is real, and C02 almost certainly contributes to it, but this doesn’t mean the planet as we know it is ending. Gore obviously feels the need to be hyperbolic to get people’s attention. But simplistic alarmism is only self-discrediting, and might mean that people pay as little attention to the new Al Gore as they did to the old.

Rich Lowry is a syndicated columnist. He can be reached via e-mail at: comments.lowry@nationalreview.com.