OK, it’s pretty much standard rhetoric in Washington to say that if you don’t do as I say, there will be massive consequences. But to say, as Gore recently did: “The survival of the United States of America as we know it is at risk;” and: “The future of human civilization is at stake” — that’s a bit much, even for the most faded and jaded political junkie.

Here’s how Gore works. He’ll cite one scientific finding that shows what he wants, and then ignore other work that provides important context. Here’s a list of his climate exaggerations from his well-publicized July 17 rant, along with a few sobering facts.

Gore: “Scientists . . . have warned that there is now a 75 percent chance that within five years the entire [North Polar] ice cap will completely disappear during the summer months.”

Fact: The Arctic Ocean was much warmer than it is now for several millennia after the end of the last ice age. We know this because there are trees buried in the tundra along what is now the arctic shore. Those trees can be dated using standard analytical techniques that have been around for decades. According to Glen MacDonald of UCLA, the trees show that July temperatures could have been 5-13°F warmer from 9,000 to about 3,000 years ago than they were in the mid-20^th century. The arctic ice cap had to have disappeared in most summers, and yet the polar bear survived!

Gore: “Our weather sure is getting strange, isn’t it? There seem to be more tornadoes than in living memory. . . .”

Fact: The reason there “seems” to be more tornadoes is because of national coverage by Doppler radar, which can detect storms that were previously missed (not to mention that every backyard tornado winds up on YouTube nowadays). Naturally, the additions are weak ones that might, if lucky, tip over a cow. If there were a true increase in tornadoes, then we would see a definite upswing in severe ones, too. If anything, the historical record indicates a slight negative trend in the frequency of major tornadoes, based upon death statistics.

Gore: “ . . . longer droughts . . . ”

Hogwash. The U.S. drought history, given by the Palmer Drought Severity Index, is readily available and extends back to 1895. There’s not a shred of evidence for “longer droughts” in recent decades. The longest ones were in the 1930s and 1950s, decades before “global warming” became “the climate crisis.”

Gore: “ . . . bigger downpours and record floods . . . ”

It’s true, U.S. annual rainfall has increased about 10 percent (three inches) in the last 100 years. But it’s equally true that this is a net benefit. Temperatures haven’t warmed nearly enough to increase the annual surface evaporation by the same amount, so what has resulted is a wetter country during the growing season. Farmers love this, because most of the nation runs a moisture deficit during the hot summer growing season. Increasing rain cuts that deficit.

Gore: “The leading experts predict that we have less than 10 years to make dramatic changes in our global warming pollution lest we lose our ability to ever recover from this environmental crisis.”

This is likely James Hansen of NASA, Gore’s climate guru. He has written and given sworn testimony that six feet of sea-level rise, caused by the rapid shedding of Greenland’s ice, could happen by 2100. Why didn’t Gore defer instead to the UN Intergovernmental Panel on Climate Change, an organization with at least a few hundred bona fide climate scientists? Its 2007 compendium estimates that the contribution of Greenland’s ice to sea level during this century will be around two inches. Gore also forgot the embarrassing truth that there has been no net change in the planetary surface temperature, as measured both by thermometers and satellites, for the last ten years.

It would be easy to go on, particularly about the preposterousness of Gore’s “solution,” which is to produce all of our electricity from solar, wind and geothermal sources within ten years. I’ll leave that for the energy economists to tear apart.

— Patrick J. Michaels is a senior fellow in environmental studies at the Cato Institute and an active member of the United Nations’ Intergovernmental Panel on Climate Change, which was awarded the 2007 Nobel Peace Prize.