Sunday , April 11 2021

Ocean blend that drives the climate that is in the surprising location



In the photo of September 2018, the photo provided by the researcher Isabela Le Bras, a probe that collects water samples and measures the temperature, salinity and pressure that are prepared to be displayed in the continental shelf of Greenland. Scientists study the circulation of the ocular circulation of the Atlantic (AMOC), a circulation of warm and cold waters that range from Greenland to the south to the tip of the Atlantic Ocean. Africa and the Indian Ocean.

Isabela Le Bras / AP

WASHINGTON – One of the main drivers of global weather is an area in the North Atlantic Ocean where the hot and cold water mixes and paddles. When the scientists first sighted this critical underwater dynamics, they found they were looking in a wrong place.

For hundreds of miles.

The consequences are still not well known, but eventually, it could change the forecasts of one of the global warming scenarios of the worst cases, still considered unlikely in this century, where mixing and climate chaos arise.

Named South Atlantic Ocean Circulation, and scientists describe it as a giant oceanic transporter belt that moves the Greenland water south to the tip of Africa and the Ocean Indian.

Hot and salty water, close to the surface, moves northwards and mixes with cool, cool water near Greenland. As the water cools and sinks, it drives a slow flow of oceans that is critical to the global climate, which affects the location of droughts and the frequency of hurricanes. It also stores carbon dioxide to catch heat deep into the ocean. The faster you move, the more hot water you send in the depths to cool off.

The area where warm water becomes in the North Atlantic is considered the motor of the conveyor belt. Scientists thought it was in the Labrador Sea, in western Greenland.

But a new international science team measured the temperature, salinity and speed of ocean currents across the Atlantic North to try to better understand the conveyor belt. The preliminary results after hundreds of measures in 21 months found that the engine was several hundred miles to where they were, said the lead author of the # 39; study, Susan Lozier, ocean science professor at Duke University. The study, published in Science magazine on Thursday, places it in Greenland, closer to Scotland.

The computer simulations that predict how the weather could change in the coming years did not exactly take into account the motor of the conveyor belt, and now they can be able to do it. Lozier and several external experts affirmed that this does not change their confidence in the models, especially because when they review models with what happens in the real world, it is found that they are generally accurate.

"It does not mean that the models do not work," said Tom Delworth, a highly qualified scientist at the geophysical laboratory at the National Oceanic and Atmospheric Administration in Princeton, New Jersey.

Carl Wunsch from MIT and other external experts said the study was useful, but noted that 21 months of study are not enough to know if this different location is temporary or permanent.

Scientists have long feared that the conveyor belt could be diminishing and, in the worst case scenario, it could even stop and cause sudden and catastrophic climate change. It is considered a possible turning point in the climate that was the premise of the scientifically inaccurate deceleration of the 2004 "The Day After Tomorrow" disaster movie.

According to studies on computer models, the United Nations Intergovernmental Panel on Climate Change reported in a previous study that "it is very unlikely" that the conveyor belt fall into this century. But the Nobel Prize winning scientific group concluded that it is likely that it will get a third lighter if the greenhouse gas emissions continue at its current pace.

A study last year found that global warming is weakening the system, saying the belt transported its slowest speed in almost 140 years of records.

"Our basic understanding that collapse is unlikely is still," said Delworth, who was not part of the study. "Our uncertainty about this prediction is high."

Follow Seth Borenstein on Twitter at @borenbears.

The Associated Press Department of Health and Science receives support from the Department of Scientific Education of the Howard Hughes Medical Institute. The AP is the only responsible for all content.


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