By Gwinne Dyer
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.
There is not much else to comment other than what the article itself clearly states:
ReplyDeleteBut 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.
1. 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.
2. 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.
3. 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."
To which I would only add: So let's just keep playing and see what happens? Or perhaps something "slightly more precautionary and sensible"?