Science & Technology

Clouding Up Man-Made Global Warming

Final dispatch from the International Conference on Climate Change in New York


March 9, New York—The participants at the final lunch of the International Climate Change Conference in New York were in a celebratory and pugnacious mood. On the one hand, these skeptics feel beleaguered—who would not?—from their antagonists constantly comparing them to Holocaust "deniers" and calling for them to be tried for "high crimes against humanity and nature." On the other hand, they are cheered by recent polls indicating public skepticism of the claims of imminent catastrophe made by climate "alarmists." In a January Pew Research Center poll, global warming came in dead last on a list of issues of concern to Americans.

At the luncheon, retired NASA climatologist John Theon rose to lament the fact that he hadn't fired James Hansen, the head of NASA's Goddard Institute for Space Studies and an ardent advocate of the idea that man-made global warming is a catastrophe in the making. The audience burst into applause when Theon called Hansen an "embarrassment." In 1988, Hansen launched global warming as a public policy issue in his testimony before a congressional committee. Theon admitted that he actually couldn't have fired Hansen, who had powerful political protectors, most notably then-Senator and later Vice President Al Gore. So had Theon tried to do it, it's much more likely that he himself would have been out on the street rather than Hansen.

Theon told the audience that while he remained silent on the issue of global warming when he retired from NASA, he now felt he needed to speak out. "This whole thing is a fraud," said Theon. "We need to educate the public about what we're going to get into unless we stop this nonsense." The nonsense being the deleterious effect that carbon rationing would have on economic growth and jobs.

Next up was Christopher Monckton, a former advisor to British Prime Minister Margaret Thatcher. Monckton delivered a high energy stem-winder mocking global warming "bedwetters" and praising the conference participants for their courage in opposing the activists' global warming juggernaut.

Aside from these celebrations, scientific presentations figured heavily in the discussions. One particularly interesting session on the third day of the conference looked at how clouds behave in computer climate models and in nature. Climatologists acknowledge that clouds represent the biggest uncertainty about the future course of global warming. University of Alabama, Huntsville, climatologist Roy Spencer talked about his recent research into how the Pacific Decadal Oscillation (PDO) may affect cloudiness and thus global average temperatures. Clouds greatly affect how much sunlight hits the earth and how much heat leaves it. While the U.N.'s Intergovernmental Panel on Climate Change (IPCC) doesn't say so directly, "it magically assumes that clouds remain the same now and forever," claimed Spencer.

In Spencer's view, climate modelers have gotten the effect of clouds on temperature backward. "When low cloud cover is observed to decrease with warming, is the cloud change the result of the warming, or is the warming the result of the cloud change?" he asked. The behavior of clouds is particularly significant, Spencer argued, because a 1 percent change in clouds could account for all of the shifts in climate over the past 2000 years.

To get an idea of the direction of causality, Spencer and his colleagues at the University of Alabama compared climate model outputs with recent satellite data. What they found is that clouds control warming (and cooling for that matter) rather than the reverse. It is generally agreed that a doubling of carbon dioxide in the atmosphere by itself would boost global temperatures by about 1 degree Fahrenheit. But the climate models all find that this increase in temperature sets off a positive feedback loop in which the atmosphere holds more water vapor which boosts temperatures further. According to the IPCC's latest report, this process could increase global average temperatures by between 2 and 11 degrees Fahrenheit by 2100.

Obviously, it makes a big difference if the temperature falls in the lower or higher end of that range. Spencer's recent research suggests that clouds are not a positive feedback, but actually operate to moderate temperature increases. If he is right, those results imply that future warming will be only about 1 degree Fahrenheit by the end of this century.

But what changes cloudiness? One well-known climatic phenomenon is the Pacific Decadal Oscillation. The North Pacific switches between two different states every 30 years or so. In the positive phase the waters are warmer and tend to warm North America and reduce rainfall. In the cool phase, temperatures fall and precipitation increases. Interestingly, when the waters are cooler, more upwelling occurs which provides more food for salmon and other fish. In addition, lower land temperatures and more precipitation make it easier for salmon to migrate inland to lay their eggs. Former Oregon state climatologist George Taylor found exactly this pattern. Salmon runs were low until the late 1990s when the PDO flipped from a warm phase to a cool phase. They rose shortly thereafter.

Members of the man-made global warming fraternity cite the fact that snowpack and precipitation declined in Washington and Oregon in the last part of the 20th century as evidence for global warming. However, Taylor argued that if one took the precipitation patterns back to the beginning of the 20th century, it becomes clear that there is a pattern in which higher precipitation and snowpack are associated with the cool phase of the PDO and reduced precipitation and snowpack correlate with the warm phase. Considering all of the data, Taylor basically found no trend in snowpack levels in the Pacific Northwest.

Spencer argued that switches in the PDO can account for about 75 percent of recent global warming. If this is true, the computer climate models are substantially overestimating future global warming, which means that the earth is likely to stay cooler than it has been for the next 20 to 30 years.

Is it a coincidence that global temperature increases flattened out at nearly the same time that the PDO flipped into its cool phase? If it turns out not to be a coincidence, then the International Climate Change Conference participants will really have something to celebrate—and so will the rest of us.

On Monday, Bailey walked among the climate change skeptics and reported on talks given by Czech Republic and European Union president Vaclav Klaus and MIT climatologist Richard Lindzen. Read about it here.

Yesterday, Bailey reported that a warmer world is a richer world; that global warming is not causing diseases to spread; and that hurricanes are not becoming stronger or more numerous. Read all about it here.

Ronald Bailey is Reason magazine's science correspondent. His book Liberation Biology: The Scientific and Moral Case for the Biotech Revolution is now available from Prometheus Books.

Bonus video from the conference: MIT's Richard Lindzen on global warming alarmists and the politicization of science: