The Forgotten Ice Age

Campaigning in Manchester, New Hampshire, last week, Newt Gingrich told an oft-repeated story to cast doubt on the science of climate change. Responding to a voter who cited the National Academy of Sciences' warnings about anthropogenic global warming, Gingrich said:

"In the mid-1970's there was a cover of Newsweek and Time that says we're in the age of a brand new glacial period and they had a cover of the Earth covered in ice. This is the 1970's. Now many of those scientists are still alive and they were absolutely convinced. I mean, if Al Gore were able to in the 1970's we would build huge furnaces to warm the planet against this inevitable coming Ice Age."

Climate change deniers have been in love with this anecdote for years. In their imagined histories, one cover story of Time and one short inside article in Newsweek transmogrified into a mass hysteria once swept the country. (Of course, everyone who was alive then seems to have forgotten it.) Even the Time cover used journalism's favorite trick phrase "a growing number" of scientists, to elide that they were growing from none to a handful, who believed that a slight cooling between the 1950's and '70s might be a harbinger of a future freeze. The article tied together a handful of micro-patterns, such as a dry spell in Africa and the UK, unseasonably cold winters in the Pacific Northwest, and attributed them to a decrease in sun light caused partly by sun-blocking particles from "farming and fuel burning."

Sen. James Inhofe of Oklahoma, the ranking member on the Environment and Public Works Committee quoted from the 1975 Newsweek story on the floor of the Senate in 2006, when he was EPW's chairman. Prominent conservative pundits and intellectuals such as George Will and the Cato Institute's David Boaz, have gleefully recounted the global cooling story in recent years. Conservatives so love this tidbit because it bolsters their central contention: that scientists don't really understand the climate and what you hear from them, via news outlets, should not be trusted. As Gingrich put it, "To what degree are we certain that we don't have patterns we don't understand yet, that may or may not involve human contributions?"

It's an appealing objection if you're looking for ways to paralyze the debate on regulating greenhouse gas emissions and preventing action to avert the catastrophe that national and international scientific associations regularly predict. But it's nonsense. If the story of global cooling demonstrates anything it's that we can protect the atmosphere through environmental regulation, because that's actually what we did then.

The great irony of the conservative affection for the global cooling story is that it proves the opposite point of what they intend.

Neither the scientific establishment nor the media ever predicted a global cooling trend with anywhere near the regularity of global warming. A handful of scientists raised the possibility of global cooling and some news outlets mentioned it. This sort of thing happens all the time, as it is part of how the scientific community separates the wheat from the chaff. But the global cooling idea wasn't supported in the same way as global warning now is, with unanimous findings and mountains of evidence. As a 2008 USA Today study of the scientific literature from the 1970s found, climate change deniers vastly overstate the extent to which scientists warned of global cooling. "There certainly was nothing like a consensus in the '70s that the Earth was going to cool," says Dan Lashof, director of the Natural Resource Defense Council's climate center. "There were one or two scientists saying we're putting stuff in the air that might cause cooling, but there was also discussion of global warming."

Scientific evidence and the ability to analyze it are far better today than they were in the 1970s. We collect more thorough data on global weather patterns, we have more sophisticated mathematical models, and we have infinitely more powerful computers to process the data through the models. So even if predictions of global cooling in the '70s had been widespread, it would not discredit more accurate findings today.

The great irony of the conservative affection for the global cooling story is that it proves the opposite point of what they intend. There was a temporary pause between World War II and about 1975 in what had been the steady rise of average global temperatures since the Industrial Revolution, and it may have been caused by unidentified natural patterns. But climate scientists now generally attribute it at least partly to the presence of particulate pollution and aerosols, such as sulfuric acid, that were being belched out by mass commercial agriculture and industrial processes such as coal burning. These particles hung in the atmosphere, where they reflected back into outer space some rays from the Sun that would otherwise have reached the Earth.

So what happened to all those pollutants? We got rid of them. These particles were not necessarily going to cause global cooling on a mass scale -- especially in the face of warming agents such as greenhouse gases -- but they caused environmental damage. Sulfates, for example, were a primary cause of acid rain. So 1990 amendments to the Clean Air Act set up a cap-and-trade system for sulfate particles. Coal plants had to reduce their emissions to the level allowed by the permits that they possessed or else incur stiff penalties. They overwhelmingly chose to comply, by installing devices to scrub their emissions or switching to cleaner burning coal. The incidence of acid rain has plummeted.

The success of the cap-and-trade regime, signed into law by President George H.W. Bush, is the primary inspiration for people who -- like Newt Gingrich circa 2007 -- want to pass a cap and trade mechanism to reduce greenhouse gas emissions.

Sulfate particle pollution has not been reduced equally in every country, or on the aggregate globally. They're outmatched by the warming effect of greenhouse gases, but they are reducing that effect a little bit, though models of climate change take that into account. Contra Gingrich, the scientists who identified the pollution problem in the '70s were not wrong about the mechanism, they just did not yet realize the greater impact that competing pollutants would have.

So the lesson a rational person should learn from the global cooling blip is that when you identify an environmental problem, you can solve it without wreaking economic havoc. Unfortunately, Gingrich, a self-described student of history, seems unwilling to learn from our success.

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