Al Gore's alarmist "documentary" has just won an Oscar. Predicting this event, here is a critique of An Inconvenient Truth
The main point of the movie is that, unless we do something very serious, very soon about carbon dioxide emissions, much of Greenland’s 630,000 cubic miles of ice is going to fall into the ocean, raising sea levels over twenty feet by the year 2100.
Where’s the scientific support for this claim? Certainly not in the recent Policymaker’s Summary from the United Nations’ much anticipated compendium on climate change. Under the U.N. Intergovernmental Panel on Climate Change’s medium-range emission scenario for greenhouse gases, a rise in sea level of between 8 and 17 inches is predicted by 2100. Gore’s film exaggerates the rise by about 2,000 percent.
Even 17 inches is likely to be high, because it assumes that the concentration of methane, an important greenhouse gas, is growing rapidly. Atmospheric methane concentration hasn’t changed appreciably for seven years, and Nobel Laureate Sherwood Rowland recently pronounced the IPCC’s methane emissions scenarios as “quite unlikely.”
Nonetheless, the top end of the U.N.’s new projection is about 30-percent lower than it was in its last report in 2001. “The projections include a contribution due to increased ice flow from Greenland and Antarctica for the rates observed since 1993,” according to the IPCC, “but these flow rates could increase or decrease in the future.”
According to satellite data published in Science in November 2005, Greenland was losing about 25 cubic miles of ice per year. Dividing that by 630,000 yields the annual percentage of ice loss, which, when multiplied by 100, shows that Greenland was shedding ice at 0.4 percent per century.
“Was” is the operative word. In early February, Science published another paper showing that the recent acceleration of Greenland’s ice loss from its huge glaciers has suddenly reversed.
Nowhere in the traditionally refereed scientific literature do we find any support for Gore’s hypothesis. Instead, there’s an unrefereed editorial by NASA climate firebrand James E. Hansen, in the journal Climate Change — edited by Steven Schneider, of Stanford University, who said in 1989 that scientists had to choose “the right balance between being effective and honest” about global warming — and a paper in the Proceedings of the National Academy of Sciences that was only reviewed by one person, chosen by the author, again Dr. Hansen.