Two recent studies indicate that the problems of carbon dioxide-induced global warming may not be as severe as some scientists originally believed.
In the first, Michael E. Schlesinger, an environmental scientist at the University of Illinois, assumed that the greenhouse effect is responsible for the alleged increase in global temperature. But Schlesinger asked whether the draconian cuts in carbon dioxide emissions that environmentalists say are necessary to combat global warming need to be made immediately. Schlesinger found that delaying proposed cuts in carbon dioxide for 10 years would lead to only slightly higher temperatures in the future. Published in the journal Nature, his study found that, with the delay, temperatures in the year 2100 would be only 5 percent higher than they would be if cuts in carbon dioxide were made immediately.
Schlesinger suggests that in the next decade scientists should engage in more research to determine just how severe global warming will be and precisely what steps are needed to deal with it. "If you want to protect your family, you are going to buy life insurance, but you are not going to buy 10 times more than is needed," he told the Los Angeles Times.
While Schlesinger warns against a disproportionate response, a study by NASA's Marshall Space Flight Institute calls into question the "fact" of global warming. Standard temperature measurements show a general warming trend since 1850. Six of the warmest years on record have occurred in the last decade, and 1990 was supposedly the warmest ever recorded.
But there are problems with standard measurements. The number of measuring sites is relatively small, making it difficult to get an accurate picture of the entire globe. Since most of the sites are on land, temperatures over most of the Ocean are unmeasured. And since most of the sites are located in cities, the measurements are increasingly polluted by the urban heat-island effect.
"The best place to measure climate is in the deep layers of the troposphere, where the reading data can be robustly correlated and avoid all the land record biases," says Marshall's John Christy.
Using satellites, Christy has been doing just that. Although the records only go back to 1979, they present a very different picture. There was no statistically significant warming over the last 12 years. And 1990 was only the fourth warmest on record, just 0.13 degree higher than the 1979–1990 mean.
Christy told syndicated columnist Warren Brookes, "If it [the greenhouse effect] is here and happening, it is very small indeed."
This article originally appeared in print under the headline "Keep Cool".