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The mixing of the ocean, which leads the climate to a surprise



WASHINGTON (AP) – One of the main drivers of global climate is the area of ​​the North Atlantic Ocean, where warmer and colder water mixes and turns. When scientists went to the first close to this critical underwater dynamo, they discovered that they were looking for the wrong place.

With hundreds of miles.

The consequences are still incomprehensible, but ultimately it could change the predictions of one of the worst global warming scenarios that are still believed to be unlikely in this century and where mixing and climate chaos are taking place.

It is called the circulation of the revolution of the Atlantic Ocean, and it is described by scientists as a giant ocean conveyor belt that moves water from Greenland to the south of Africa and the Indian Ocean.

Warm, salty water near the surface moves north and mixes with cold, fresher water near Greenland. As the water cools and sinks, it causes slow ocean circulation, which is essential for the global climate, affecting the drought and hurricane frequency. It also stores heat trapping carbon dioxide deep in the ocean. The faster it moves, the warmer the water is taken to the depths to cool.

The conveyor belt engine is considered to be the area where warm water turns into the North Atlantic. Scientists believed it was in the Labrador Sea west of Greenland.

But then the new international team of scientists measured temperature, salinity, and the speed of the ocean stream across the North Atlantic to try and better understand the conveyor belt. Initial results after hundreds of measurements in 21 months revealed that the engine was several hundred miles east of where they understood it, said research manager Susan Lozier, ocean science professor at Duke University. In a study published on Thursday in Science, it is located east of Greenland, closer to Scotland.

Computer simulations that predict how the climate may change in the coming years did not affect exactly where the conveyor belt engine is, and now they will. Lozier and a number of external experts said it did not change their confidence in the models, especially as they are considered general in testing models with what is happening in the real world.

"It doesn't mean that all models are wrong," said Tom Delworth, senior scientist at the National Oceanic and Atmospheric Geophysical Laboratory in Princeton, New Jersey.

MIT Carl Wunsch and other external experts said the study was useful but indicated that 21 months of study was not enough to find out whether this different location was temporary or permanent.

Scientists have long been afraid that the conveyor belt may slow down and, at worst, could even stop and cause sudden and catastrophic climate change. This is considered to be a potential climax of climate, which was a precondition for scientifically inaccurate disaster film "Day after tomorrow".

Based on computer models, the United Nations Intergovernmental Panel on Climate Change, reported in a previous study, is "highly unlikely" that the conveyor belt will collapse in this century. But the Nobel Prize winning scientific committee concluded that if greenhouse gas emissions continue to grow at the current pace, it is likely to increase by a third.

The study last year found that global warming weakens the system by saying that the conveyor belt has been moving at a slower rate in almost 140 years.

"Our basic knowledge that collapse is still unlikely," said Delvard, who was not part of the study. "Our uncertainty about this forecast is high."

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Follow Seth Borenstein on Twitter at @borenbears.

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The Associated Press Health & Science Department receives support from the Science Education Department of the Howard Hughes Medical Institute. All content is the sole responsibility of the AP.


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