Dusk On Earth

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This column was written by Bill McKibben.
Even for Americans, constitutionally convinced that there will always be a second act, and a third, and a do-over after that, and, if necessary, a little public repentance and forgiveness and a Brand New Start--even for us, the world looks a little Terminal right now.

It's not just the economy. We've gone through swoons before. It's that gas at $4 a gallon means we're running out, at least of the cheap stuff that built our sprawling society. It's that when we try to turn corn into gas, it sends the price of a loaf of bread shooting upwards and starts food riots on three continents. It's that everything is so inextricably tied together. It's that, all of a sudden, those grim Club of Rome types who, way back in the 1970s, went on and on about the "limits to growth" suddenly seem... how best to put it, right.

All of a sudden it isn't morning in America, it's dusk on planet Earth.

There's a number--a new number--that makes this point most powerfully. It may now be the most important number on Earth: 350. As in parts per million (ppm) of carbon dioxide in the atmosphere.

A few weeks ago, our foremost climatologist, NASA's Jim Hansen, submitted a paper to Science magazine with several co-authors. The abstract attached to it argued--and I have never read stronger language in a scientific paper--"if humanity wishes to preserve a planet similar to that on which civilization developed and to which life on earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm." Hansen cites six irreversible tipping points--massive sea level rise and huge changes in rainfall patterns, among them--that we'll pass if we don't get back down to 350 soon; and the first of them, judging by last summer's insane melt of Arctic ice, may already be behind us.

So it's a tough diagnosis. It's like the doctor telling you that your cholesterol is way too high, and if you don't bring it down right away, you're going to have a stroke. So you take the pill, you swear off the cheese, and, if you're lucky, you get back into the safety zone before the coronary. It's like watching the tachometer edge into the red zone and knowing that you need to take your foot off the gas before you hear that clunk up front.

In this case, though, it's worse than that because we're not taking the pill and we are stomping on the gas--hard. Instead of slowing down, we're pouring on the coal, quite literally. Two weeks ago came the news that atmospheric carbon dioxide had jumped 2.4 parts per million last year--two decades ago, it was going up barely half that fast.

And suddenly, the news arrives that the amount of methane, another potent greenhouse gas, accumulating in the atmosphere, has unexpectedly begun to soar as well. Apparently, we've managed to warm the far north enough to start melting huge patches of permafrost and massive quantities of methane trapped beneath it have begun to bubble forth.

And don't forget: China is building more power plants, India is pioneering the $2,500 car, and Americans are converting to TVs the size of windshields that suck juice ever faster.

Here's the thing. Hansen didn't just say that, if we didn't act, there was trouble coming; or, if we didn't yet know what was best for us, we'd certainly be better off below 350 ppm of carbon dioxide in the atmosphere. His phrase was: "...if we wish to preserve a planet similar to that on which civilization developed." A planet with billions of people living near those oh-so- floodable coastlines. A planet with ever more vulnerable forests. (A beetle, encouraged by warmer temperatures, has already managed to kill ten times more trees this year than in any previous infestation across the northern reaches of Canada. This means far more carbon heading for the atmosphere, and apparently dooms Canada's efforts to comply with the Kyoto Protocol, already in doubt because of its decision to start producing oil for the US from Alberta's tar sands.)

We're the ones who kicked off the warming; now, the planet is starting to take over the job. Melt all that Arctic ice, for instance, and suddenly the nice white shield that reflected 80 percent of incoming solar radiation back into space has turned to blue water that absorbs 80 percent of the sun's heat. Such feedbacks are beyond history, though not in the sense that Francis Fukuyama had in mind.

And we have, at best, a few years to short-circuit them--to reverse course. Here's the Indian scientist and economist Rajendra Pachauri, who accepted the Nobel Prize on behalf of the Intergovernmental Panel on Climate Change last year (and, by the way, got his job when the Bush Administration, at the behest of Exxon Mobil, forced out his predecessor): "If there's no action before 2012, that's too late. What we do in the next two to three years will determine our future. This is the defining moment."

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