Study finds that Atlantic circulation is approaching a ‘devastating’ tipping point Oceans

Study finds that Atlantic circulation is approaching a ‘devastating’ tipping point  Oceans

The movement of the Atlantic Ocean is heading toward a tipping point that represents “bad news for the climate system and humanity,” a study has found.

The scientists who carried out the research said they were shocked by the expected speed of the collapse once this point was reached, although they said it was not yet possible to predict how quickly it would happen.

Using computer models and previous data, researchers have developed an early warning indicator for the collapse of the Atlantic Overturning Circulation (Amoc), a vast system of ocean currents that is a key component in regulating global climate.

They found that AMOC is already on track for an abrupt transformation, which has not happened in more than 10,000 years, and which will have dire effects on large parts of the world.

The AMOC, which includes part of the Gulf Stream and other powerful currents, is a marine conveyor belt that carries heat, carbon and nutrients from the tropics toward the Arctic Circle, where it cools and sinks into the depths of the ocean. This churning helps distribute energy around the Earth and moderates the effect of human-caused global warming.

Amok drawing

But the system is being eroded by melting Arctic glaciers and ice sheets faster than expected, pouring fresh water into the sea and impeding the sinking of saltier, warmer waters from the south.

AMOC stock has fallen by 15% since 1950, and is at its weakest point in more than a thousand years, according to previous research that raised speculation about an impending collapse.

So far there has been no consensus on how dangerous it is. One study last year, based on changes in sea surface temperatures, suggested that the tipping point could occur between 2025 and 2095. However, the UK Met Office said that large and rapid changes in the AMOC were “extremely unlikely” in the 21st century.

The new study, published in the journal Science Advances, broke new ground by looking for warning signs in salinity levels at the southern tip of the Atlantic Ocean between Cape Town and Buenos Aires. By simulating changes over 2,000 years on computer models of global climate, she found that a slow decline could lead to a sudden collapse over less than 100 years, with catastrophic consequences.

The newspaper said the results provided a “clear answer” about whether such an abrupt shift was possible: “This is bad news for the climate system and humanity, since until now one might have thought that AMOC tipping was just a theoretical concept and that tipping would disappear.” “Once you consider the complete climate system, with all its additional feedbacks.”

It also identified some of the consequences of the collapse of AMOC. Sea levels in the Atlantic Ocean will rise by one meter in some areas, submerging many coastal cities. Wet and dry seasons will reverse in the Amazon, potentially pushing the already vulnerable rainforest past its tipping point. Temperatures around the world will fluctuate erratically. The southern hemisphere will become warmer. Europe will cool significantly and rainfall will decrease. While this may sound attractive compared to the current heating trend, the changes will happen ten times faster than they are now, making adaptation almost impossible.

“What surprised us was the rate at which fly-tipping occurs,” said the study’s lead author, René van Westen, from Utrecht University. “It would be devastating.”

He said there is not enough data yet to determine whether this will happen next year or in the next century, but when it does, the changes are irreversible on human time scales.

Meanwhile, the direction of travel is undoubtedly moving in an alarming direction.

“We’re moving toward that. That’s kind of scary,” Van Westen said. “We need to take climate change seriously.”

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