In his Washington Post column today, George Will writes that climatologists were all forecasting "global cooling" back in the 1970s, and, because they were so spectacularly wrong about that, we shouldn't pay much heed to their current predictions about catastrophic global warming, either. My, what a fascinating column idea! Or, rather, it might have been fascinating if this was only the first time Will had tried this stunt. But it's not. He's peddled the "global cooling" canard numerous times before, and it's been debunked again and again. Why George Will would want to use his platform to mislead readers rather than enlighten them is his own business, I guess, but someone has to sweep up the wreckage, so here goes.
The short version of the debunking goes like this: Back in the 1970s, yes, a few popular media outlets like Newsweek were, in fact, making overblown claims about a coming ice age, but if you read what actual scientists were writing—say, in this 1972 National Science Board report or in this 1975 National Academy of Sciences report—it's clear the mainstream consensus held that there simply wasn't enough evidence (yet) to estimate the future trajectory of the Earth's climate.
As an example, one oft-cited paper in Science from 1971, by S. Ichtiaque Rasool and Stephen Schneider, observed, correctly, that greenhouse gases like carbon dioxide had a warming effect on the earth, while aerosols and particulate pollution like smog had a cooling effect. They just weren't sure which effect would predominate, though they noted that sufficiently large amounts of aerosol pollution could theoretically bring about a new ice age. The paper had a few flaws (for one, it underestimated the sensitivity of the earth's climate to carbon dioxide by a factor of about three), but it's basically in line with what we know now: Clean-air laws have helped mop up particulate pollution over the years, but greenhouse-gas emissions are still increasing, and that's why the planet is heating up.
If you're eager for a more thorough skewering of Will's nonsense, see Joe Romm or this lucid review essay in the Bulletin of the American Meterological Society debunking the whole "scientists feared global cooling in the '70s" myth. That latter essay, by the way, isn't difficult to find. Will laced his column with a bunch of scholarly-seeming citations—most of them from the popular press—as if to imply that he did extensive research in assembling this column. He didn't. The first or second result from a simple Google search on "global cooling" is a Wikipedia entry that points anyone who's genuinely curious in the proper direction. Will just chose to ignore all this, and then filled the rest of his column with standard right-wing shibboleths. (His riff on how Obama science adviser John Holdren once advised Paul Ehrlich—who made a bad bet on the price of commodities back in the 1980s—originates with John Tierney, and while it's fun trivia, it's radically unclear to me how this episode somehow undermines the vast body of climate science research out there.)
Meanwhile, in the actual news section of The Washington Post today comes this report: "The pace of global warming is likely to be much faster than recent predictions, because industrial greenhouse gas emissions have increased more quickly than expected and higher temperatures are triggering self-reinforcing feedback mechanisms in global ecosystems, scientists said Saturday." Hey, maybe these so-called "scientists" are all full of it! But it'll take a good deal more than George Will's amateur hackwork to prove it.