Exploding myth of 1970s global cooling "consensus"
When global warming skeptics set out to undermine the current scientific consensus that the planet is warming up, they often point to a 1975 article in Newsweek magazine that was titled "The cooling world." The story cited research on increasing Northern Hemisphere snow and ice, and other work on the shading effects of atmospheric dust kicked up by human activity, and suggested that the planet was sliding toward a new Ice Age. Other articles, pegged to some very cold U.S. winters in the 1970s, made similar points.
The scientific consensus then, the skeptics argue, was that the planet was cooling down.
"Back then, the 'coolers' had the upper hand because, indeed, the planet was cooling," writes one. "But nature quickly shifted gears ... Needless to say, the abrupt shift in the climate caused almost as abrupt a shift in the balance of scientists who predictably followed the temperature."
Their argument is that scientific "consensus" shifts with the winds of politics and research funding priorities, and can't be relied on as the basis for making public policy.
But in the September issue of the Bulletin of the American Meteorological Society, a trio of authors reports on a study of the scientific literature and the popular press of the day. They conclude that climate scientists were struggling in the 1970s to understand the forces of global climate change, and to draw together the findings of researchers working in a variety of different fields.
There was no consensus yet, they say. But the prevailing opinion was that global warming, driven by the increasing levels of carbon dioxide in the atmosphere, was the dominant global trend and the larger worry for mankind on the "immediate" scale of decades to centuries.
The authors surveyed the peer-reviewed scientific literature from 1965 to 1979 and found seven articles that presented evidence of global cooling, 20 that were neutral on the issue, and 44 that concluded the climate was warming. The "cooling" articles received far fewer citations in other research than the "warming" articles, a measure of which climate trend dominated the scientific thinking of the time.
They also point to a 1979 conference of top climate scientists at Woods Hole, Mass., convened by the National Research Council. The panel sorted through the science of the day and concluded that, despite a great deal of remaining uncertainty, there was enough evidence for global warming to warrant public action. "A wait-and-see policy may mean waiting until it is too late," their report concluded.
"Global cooling was never more than a minor aspect of the scientific climate change literature of the era, let alone the scientific consensus," the paper's authors conclude.
The AMS paper also raps Newsweek and others in the popular press of the 1970s for seeking out and exploiting the "dramatic or new," at the expense of nuance and accuracy. Even so, they found "no consensus" among journalists of the time, either. (In our defense, I'd argue that, taken as a whole, the journalism of that era accurately reflected the unsettled nature of the scientific opinion at the time.)
The authors argue that today's global warming skeptics seize selectively on news clips and quotes from the 1970s to bolster their argument that the scientific community back then had concluded that the planet was cooling. They use their snippets to undermine the credibility of today's scientists, who - backed by a much more mature science of global climatology - overwhelmingly agree that the planet is warming, "very likely" due to the burning of fossil fuels.
The "cooling concensus" of the 1970s, they conclude, is a myth. And "in this case the primary use of the myth is in the context of attempting to undermine public belief in and support for the contemporary scientific consensus about anthropogenic climate change..."
But decide for yourself. You can read the whole article here. Scroll down to the PDF link for the piece by Thomas C. Peterson, of the National Climatic Data Center; William M. Connolley, of the British Antarctic Survey; and John Fleck, of the Albuquerque Journal.