Wednesday, March 14, 2007

A report last June by the National Academies seemed to contradict Mr. Gore’s portrayal of recent temperatures as the highest in the past millennium. Instead, the report said, current highs appeared unrivaled since only 1600, the tail end of a temperature rise known as the medieval warm period.

Roy Spencer, a climatologist at the University of Alabama, Huntsville, said on a blog that Mr. Gore’s film did “indeed do a pretty good job of presenting the most dire scenarios.” But the June report, he added, shows “that all we really know is that we are warmer now than we were during the last 400 years.”

Geologists have documented age upon age of climate swings, and some charge Mr. Gore with ignoring such rhythms.

“Nowhere does Mr. Gore tell his audience that all of the phenomena that he describes fall within the natural range of environmental change on our planet,” Robert M. Carter, a marine geologist at James Cook University in Australia, said in a September blog. “Nor does he present any evidence that climate during the 20th century departed discernibly from its historical pattern of constant change.”

The consensus catechism about global warming has six tenets: 1. Global warming is happening. 2. It is our (humanity's, but especially America's) fault. 3. It will continue unless we mend our ways. 4. If it continues we are in grave danger. 5. We know how to slow or even reverse the warming. 6. The benefits from doing that will far exceed the costs.

Only the first tenet is clearly true, and only in the sense that the Earth warmed about 0.7 degrees Celsius in the 20th century.

Eighty-five percent of Americans say warming is probably happening, and 62 percent say it threatens them personally. The National Academy of Sciences says the rise in the Earth's surface temperature has been about one degree Fahrenheit in the past century. Did 85 percent of Americans notice? Of course not. They got their anxiety from journalism calculated to produce it.

Science magazine (Dec. 10, 1976) warned of "extensive Northern Hemisphere glaciation." Science Digest (February 1973) reported that "the world's climatologists are agreed" that we must "prepare for the next ice age." The Christian Science Monitor ("Warning: Earth's Climate is Changing Faster Than Even Experts Expect," Aug. 27, 1974) reported that glaciers "have begun to advance," "growing seasons in England and Scandinavia are getting shorter" and "the North Atlantic is cooling down about as fast as an ocean can cool." Newsweek agreed ("The Cooling World," April 28, 1975) that meteorologists "are almost unanimous" that catastrophic famines might result from the global cooling that the New York Times (Sept. 14, 1975) said "may mark the return to another ice age." The Times (May 21, 1975) also said "a major cooling of the climate is widely considered inevitable" now that it is "well established" that the Northern Hemisphere's climate "has been getting cooler since about 1950."

In fact, the Earth is always experiencing either warming or cooling.

Let’s not dispute the earth’s temperature. It’s warmer than it used to be ... The North American ice sheets reached their largest expanse about 18,000 years ago and then began to recede. Within 5000 years they had pulled back considerably but still reached south as far as central Ohio. After another thousand years, however, the U.S. was largely ice-free. Needless to say, there have been no glaciers reported in Iowa as long as anyone can remember. It’s warmer now.

Now for an inconvenient truth about CO2 sources — nature generates about 30 times as much of it as does man. Yet the warming worriers are unconcerned about nature’s outpouring. They — and Al Gore — are alarmed only about anthropogenic CO2, that 3.2 percent caused by humans.

They like to point fingers at the U.S., which generated about 23 percent of the world’s anthropogenic CO2 in 2003, the latest figures from the Energy Information Administration. But this finger-pointing ignores yet another inconvenient truth about CO2. In fact, it’s a minor contributor to the greenhouse effect when water vapor is taken into consideration. All the greenhouse gases together, including CO2 and methane, produce less than two percent of the greenhouse effect.

When water vapor is put in that perspective, then anthropogenic CO2 produces less than 0.1 of one percent of the greenhouse effect.

I regard consensus science as an extremely pernicious development that ought to be stopped cold in its tracks. Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled. Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you're being had.

Let's be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world.

In science consensus is irrelevant. What is relevant is reproducible results. The greatest scientists in history are great precisely because they broke with the consensus. There is no such thing as consensus science. If it's consensus, it isn't science. If it's science, it isn't consensus. Period.

Consensus is invoked only in situations where the science is not solid enough.

Labels: Science