A World in Peril, the Great Atlantic Conveyor

One thing all petro-pols learn quickly is how to turn their backs on calamities closing in on us. And, yes, that includes Justin Trudeau. He's in the club.

So, when scientists studying the rapid decline in the Gulf Stream, now at its weakest in 1,600 years, the weakest ever recorded, warn that further disruption of the global currents so critical to regulating global climate must be avoided "at all costs" they'll probably be too busy pimping fossil fuels, even the really filthy stuff, to pay it any notice.

C'mon, bring it on boys. Tell us that "the science isn't in." The Gulf Stream has failed in the past but we're still here, right? Who knows, maybe extinction is actually good for us. And don't forget the economy. Remember you want that holiday in Mexico next year, eh? Besides it's out of our control, nothing we can do about it. It's not a man-made thing. There's no proof. Some say this, some say that. No one knows. Can't tell.

Past collapses of the giant network have seen some of the most extreme impacts in climate history, with western Europe particularly vulnerable to a descent into freezing winters. A significantly weakened system is also likely to cause more severe storms in Europe, faster sea level rise on the east coast of the US and increasing drought in the Sahel in Africa. 

The new research worries scientists because of the huge impact global warming has already had on the currents and the unpredictability of a future “tipping point”. 

The currents that bring warm Atlantic water northwards towards the pole, where they cool, sink and return southwards, is the most significant control on northern hemisphere climate outside the atmosphere. But the system, formally called the Atlantic Meridional Overturning Circulation (Amoc), has weakened by 15% since 1950, thanks to melting Greenland ice and ocean warming making sea water less dense and more buoyant. 

This represents a massive slowdown – equivalent to halting all the world’s rivers three times over, or stopping the greatest river, the Amazon, 15 times. Such weakening has not been seen in at least the last 1,600 years, which is as far back as researchers have analysed so far. Furthermore, the new analyses show the weakening is accelerating.

“From the study of past climate, we know changes in the Amoc have been some of the most abrupt and impactful events in the history of climate,” said Prof Stefan Rahmstorf, at the Potsdam Institute for Climate Impact Research in Germany and one of the world’s leading oceanographers, who led some of the new research. During the last Ice Age, winter temperatures changed by up to 10C within three years in some places.

“We are dealing with a system that in some aspects is highly non-linear, so fiddling with it is very dangerous, because you may well trigger some surprises,” he said. “I wish I knew where this critical tipping point is, but that is unfortunately just what we don’t know. We should avoid disrupting the Amoc at all costs. It is one more reason why we should stop global warming as soon as possible.”

"Well, we have your point and we're deeply concerned. Unfortunately the prime minister is busy pimping bitumen at the moment and then he's got an election next year but we're sure he'll want, really want, to free up some time to chat with you about this. Maybe after the election or, perhaps, the election after that. And here's something that will cheer you up. By 2025, roughly, we're planning to end fossil fuel subsidies. We mean it this time."