Global Warming is Dead. Long Live Global Warming!

Baby, it's cold outside. Global warming must be over.

Posted Jan 06, 2010

coldBaby, it's cold outside. Not just up here in New England, but across continents. Citrus farmers in Florida are worried about freezing crops. Britain is experiencing its worst cold spell in three decades. There's record snowfall in China.

You know what this means, of course. Brace yourself for yet another spate of obituaries declaring the end of global warming.

GoreThe jokes I can tolerate well enough. I mean, who, in the midst of shoveling snow, hasn't been tempted to throw out a one-liner to their neighbor like, "hey, what happened to global warming?" Or "tell Al Gore I have an extra shovel for him when he's done with his next book." It's tough to resist the temptation–it's the cold-climate equivalent of saying, "man, it's like a sauna in here" when you are, indeed, taking a sauna.

But it's the person who offers supposedly serious conclusions based on limited, recent observation that's tougher to swallow. It's beyond me how someone can look a camera, editor, or blogosphere in the eye and, with straight face, suggest that a few weeks of frigid winter temperatures put a resolute end to multi-year trends. It's as ridiculous as suggesting that because your uncle smoked until he was 90, the link between cigarettes and cancer has been dispelled.

We simply read too much into recent events in assessing present conditions and forecasting the future. We put so much stock in what has just happened that we lose sight of the broader trajectory that brought us to this point. Recent developments are more salient and therefore more influential in how we think.

So the past few weeks have been bitterly cold? Well, then, the earth can't be getting warmer. It's little different than the bettor's overconfidence that the three teams that won last week's relatively meaningless football games will also win the rematches this weekend when the NFL playoffs start. Or the all-you-can-eat buffeteer's certainty that he's never going to be hungry again after inhaling half his own weight in shrimp cocktail.

And just as it demonstrates the power of recency, the inevitable surge in global warming skepticism after a cold spell also illustrates what seems to be our society's increasing imperviousness to data. As Michael Specter suggests in his new book Denialism, in many respects, we seem to be devolving into a culture in which we'd rather rely on gut feeling than scientific inquiry.

When I was in graduate school, I once heard a psychologist I greatly admire caution against reading too much into isolated examples. "The plural of anecdote is not data," I recall hearing her say more than a decade ago. But all too often, it would seem that more of us subscribe to the sentiment underlying a different quotation, namely Mark Twain's claim that the three varieties of lies are "lies, damned lies, and statistics."

statsSure, statistics can be manipulated. In fact, I hear that's true 87% of the time. But this is precisely why reasonable scientists don't base their conclusions on just one study, one set of data, or one research team. Consider the Climategate controversy a few months ago surrounding those hacked emails from British climatologists. Some trumpeted that these emails were proof of fraudulent research practices (they weren't, as a close reading of the actual messages reveals). But even if they were, it's not as if these were the only data indicating a clear trajectory of increasing temperatures over decades.

When I teach research methods to college students, I emphasize all semester long this notion that the plural of "anecdote" isn't "data." But we lose sight of this premise too easily in daily life. How else to explain why we allow a couple weeks of cold temperatures to influence us more than the finding that 2009 was one of the top 10 warmest years in recorded history?

Or why we become convinced by a few instances of co-occurrence that vaccination causes autism?

Or why we believe we've experienced a psychic moment when the long-lost friend we suddenly dreamed about the other night phones out of the blue?

Your gut can be misleading.

No, science isn't perfect. After all, it's inherently a process of trial and error. But when we read too much into singular events, recent developments, coincidences, and regular fluctuations, we don't stand even a chance of learning anything meaningful about the world around us. Without stepping back to take a big-picture and–dare I say it?–an empirical/statistical view, we get too distracted by the random blips to truly understand what's on the radar screen in front of us.

bundledSo strap on your boots, gloves, and thermal underwear, and remember, this is what winter feels like. Sometimes it's cold, sometimes it's damned cold, and sometimes it's not so bad. A colder-than-average January doesn't disprove global warming any more than one warmer-than-average month confirms it.

Or as Twain himself might have put it, the rumors of global warming's demise have been greatly exaggerated.