Climate scientists are a fickle lot, global warming doubters assert. Sure, almost all of them now seem pretty sold on the idea that the planet is heating up. But back in the 1970s, didn't they just as confidently proclaim that that Earth was cooling down? Why should we believe them now?
Well, for starters, because the ice age meme is distortion. In an era when climate measurements and modeling were in their infancy, there were a few scientists who believed that Earth might be cooling, but they were always in the minority. A review of scientific literature from 1965 to 1979, published in the American Meteorological Society journal in 2008, revealed that 86 percent of the articles presented evidence of a warming trend, and that those articles also were the ones most often cited by other researchers.
The concern about global warming also was reflected in the findings of a 1979 panel convened by the National Research Council, which concluded that increased greenhouse gas output was a serious environmental risk. That report doesn't even mention the possibility of cooling, or an ice age [source: Peterson et al.].