Published March 02, 2010
Al Gore's defense of global-warming hysteria in Sunday's New York Times has many flaws, but I'll focus on just one whopper -- where the "Inconvenient Truth" man states the opposite of scientific fact.
Gore wrote, "The heavy snowfalls this month have been used as fodder for ridicule by those who argue that global warming is a myth, yet scientists have long pointed out that warmer global temperatures have been increasing the rate of evaporation from the oceans, putting significantly more moisture into the atmosphere -- thus causing heavier downfalls of both rain and snow in particular regions, including the Northeastern United States."
It's an interesting theory, but where are the facts?
According to "State of the Climate" from the National Oceanic and Atmospheric Administration, "Global precipitation in 2009 was near the 1961-1990 average." And there was certainly no pattern of increasing rain and snow on America's East Coast during the post-1976 years, when NOAA says the globe began to heat up.
So what was it, exactly, that Gore's nameless scientists "have long pointed out"? A 2008 report from the Intergovernmental Panel on Climate Change, "Climate Change and Water," says climate models "project precipitation increases in high latitudes and part of the tropics." In other areas, the IPCC reports only "substantial uncertainty in precipitation forecasts."
In other words, the IPCC said that its models predicted some increases in rain or snow -- not observed them. And only in high latitudes or the tropics, which hardly describes New York or Washington, DC.
In fact, recent research actually contradicts Gore's claims about "significantly more water moisture in the atmosphere."
In late January, Scientific American reported: "A mysterious drop in water vapor in the lower stratosphere might be slowing climate change," and noted that "an apparent increase in water vapor in this region in the 1980s and 1990s exacerbated global warming."
The new study came from a group of scientists, mainly from the NOAA lab in Boulder. The scientists found: "Stratospheric water-vapor concentrations decreased by about 10 percent after the year 2000 . . . This acted to slow the rate of increase in global surface temperature over 2000 to 2009 by about 25 percent."
Specifically, the study found that water vapor rising from the tropics has been reduced, because it has gotten cooler there (another inconvenient truth). A Wall Street Journal headline summed it up: "Slowdown in Warming Linked to Water Vapor."
Moisture in the lower stratosphere (about 8 miles above the earth's surface) has been going down, not up.
Aside from clouds, water vapor accounts for as much as two-thirds of the earth's greenhouse-gas effect. Water vapor traps heat from escaping the atmosphere -- but clouds have the opposite effect (called "albedo") by reflecting the sun's energy back into space. And snow on the ground from the IPCC's predicted precipitation in high latitudes would have the same cooling effect as clouds.
What the new research suggests is that changes in water vapor may well trump the effect of carbon dioxide (only a fraction of which is man-made) and methane (which has mysteriously slowed since about 1990).
This raises an intriguing question: Since the Environmental Protection Agency declared that it has the authority to regulation carbon emissions because of their presumed effect on the global climate, why hasn't the EPA also attempted to regulate mist and fog?
Alan Reynolds, a Cato Institute senior fellow, is author of "Income and Wealth."