The Atlantic's chilling secret finally revealed

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For over a century, a region of cold water south of Greenland has resisted the overall warming of the Atlantic Ocean. A new study identifies the causes as a long-term weakening of a major ocean circulation system.

Researchers at the University of California, Riverside show that only one explanation fits the observed ocean temperatures and salinity patterns. The Atlantic Meridional Circulation is certainly slowing down. This massive system helps regulate climate by moving warm, salty water northward and cooler water southward at depth.

The AMOC system acts like a giant conveyor belt, delivering heat and salt from the tropics to the North Atlantic. The slowdown means that less warm and salty water reaches the subpolar region, resulting in the cooling and refreshing observed south of Greenland.

The data showed that only models simulating a weakened AMOC matched the real data. Models assuming a stronger circulation did not even come close to matching these data. The studies also confirmed that the weakening AMOC correlates with reduced salinity. This is another clear signal that less warm and salty water is being transported north.

The implications are far-reaching, as the anomaly in southern Greenland is important not only for its unusualness, but also because it is one of the most sensitive areas to changes in ocean circulation. It will affect the weather in Europe, changing precipitation and shifting the jet stream.

The slowdown could also disrupt marine ecosystems, as changes in salinity affect where species can live. As the climate system gradually changes, the influence of southern Greenland will increase. The study's lead author notes that the technique used gives humanity a chance to understand how the system has changed and where it is likely to go if greenhouse gases continue to rise.

Source:ScienceDaily