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Friday, September 27, 2013

Gwynne Dyer: No time to be trigger happy on climate

Wind turbines used to generate electricity are seen at a wind farm in Guazhou, 950km (590 miles) northwest of Lanzhou, Gansu Province September 15, 2013. (REUTERS/Carlos Barria)
Wind turbines used to generate electricity are seen at a wind farm in Guazhou, 950km (590 miles) northwest of Lanzhou, Gansu Province September 15, 2013. (REUTERS/Carlos Barria)

by Gwynne Dyer, special to QMI Agency, Fort Murray Today, September 25, 2013

American campaign strategist James Carville coined the phrase “It’s the economy, stupid” to focus the attention of campaign workers on the one key issue that could get Bill Clinton elected president in the 1992 U.S. election.
Alas, the authors of the Fifth Assessment of the Intergovernmental Panel on Climate Change (IPCC), out Friday, have no such sage to guide them. They’ll have to make do with me.
The 800-odd authors of the report are all scientists. They are selected by their fellow scientists in the various disciplines relevant to climate change, and they are doing this work at the behest of the world’s governments, not as an outside pressure group. It is, after all, the Intergovernmental Panel on Climate Change.
But scientists are very cautious people. They won’t go one millimetre beyond what the evidence makes indisputable, knowing that they will be attacked by rival scientists if they do. They are much more comfortable talking about probabilities rather than certainties. They are, in other words, a nightmare for journalists who have to transmit their findings to the world.
Of the nearly 100 scientists I have interviewed on climate change during the past five years, not one doubted that global warming is a big and frightening problem. Indeed, there was often an undercurrent of panic in their remarks. But when it comes to writing official reports, they retreat into science-speak.
So the Second Assessment of the IPCC, published in 1995, said that it was more than 50% likely that human emissions of greenhouse gases were contributing to global warming. The Third Assessment, in 2001, raised the likelihood to 66%. The Fourth, in 2007, upped the ante to 90%, and the Fifth, this week, says 95%.
But how do you make a headline out of that? How much warming? How fast? And with what effects on human beings? The latest report runs to thousands of pages, and the answers are buried among the statistics.
What would Jim Carville do? He’d say: It’s the feedbacks, stupid.
Without the feedbacks, we could go on burning fossil fuels and cutting down the forests, and the average global temperature would creep up gradually, but so slowly that most inhabited parts of the planet would stay liveable for a long time.
But if we trigger the feedbacks, the whole thing goes runaway.
The feedbacks are natural sources of warming that we activate by raising the average global temperature just one or two Celsius degrees. There are three main ones.
As the highly reflective ice and snow that covers most of the polar regions melts, the rate at which the sun’s heat is absorbed goes up steeply over a large part of the planet. We are creating a new warming engine that we can’t turn off.
The polar warming melts the frozen ground and coastal seabed (permafrost) in the Arctic, which then release massive quantities of methane that causes further warming.
And the oceans, as they warm, release some of the vast quantities of carbon dioxide they absorbed in the past, simply because warmer water can contain less dissolved gas.
Those are the killer feedbacks. At least five times in the past 500 million years, the planet has lurched suddenly into a climate five to six Celsius degrees higher than now, and in every case these feedbacks are the prime suspects.
We don’t need to build the gun that kills us. We just have to pull the trigger. And we are playing with the trigger now.
— Gwynne Dyer is an independent journalist whose articles are published in 45 countries.

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