Climate warning: Antarctica’s sea currents slowing sooner than expected

Stopping the Antarctic bottom current, which is considered one of the many dangers arising from climate change, It’s happening much sooner than expected.. This is stated in a study published by an international research group. Nature Climate Change, He warned of the butterfly effect this halt in flow could have on the rest of the planet.

The Antarctic Current carries trillions of tons of cold, dense, oxygen-rich water from the continental shelf into the ocean depths. as if it were a huge underwater waterfall.

This Antarctic ‘water table’ then spreads northward across the Pacific, Indian and Atlantic oceans, along the seabed and along deep ocean currents, and then slowly rises again thousands of kilometers away.

Just like the lung pumps oxygen into the blood, AABW redistributes heat, carbon, oxygen and nutrients across the planet. Therefore, its operation is vital to maintain the good functioning of the climate and ecosystems. It is also the main pathway through which oxygen reaches the depths of the ocean.

Consequences of this fact

This slowdown has various consequences. On the one hand, can disrupt the climate system, On the other hand, it narrows the habitable range of species and may ultimately limit the ocean’s capacity to act as a carbon sink, ultimately impacting on the current climate change process.

Scientists had already predicted that this could be one of the consequences of climate change, but they never imagined that it would happen decades earlier than expected.

“The slowdown could disrupt the connection between the Antarctic coast and the ocean depths,” the authors of this study wrote in an article in the journal. Speech Where will they announce the results?.

Already reduced by 30 percent

Specifically, the analyzed data show that the circulation of this stream has decreased by almost a third (30%) in the last three decades. AND This already has consequences, as oxygen levels at depth are already dropping. just as the models predicted.

Behind this situation is the melting of the ice in the region as a result of climate change. And when the ice melts, the water formed is at a lower temperature than the temperature normally found at the surface. “Cold waters are less dense and therefore less likely to sink, which slows marine circulation,” the scientists explain. In other words, The deep, cold layer of water rich in oxygen is replaced by warmer water containing less oxygen.

Without oxygen and with more CO2

Lack of oxygen has effects on all marine life. Although deep ocean fauna have adapted to living in oxygen-scarce conditions, having little is not the same as having nothing.

without enough oxygen Habitable areas will decrease – estimated by up to 25% – and abyssal species will be forced to adapt, move, or die.

But the problems do not only affect this specific part of the world. If the current stops It will become a factor that increases climate change.

And the Overturn Current carries carbon dioxide, in addition to oxygen and heat, deep into the ocean. Once there, it is stored and removed from the atmosphere. But this way If this storage capacity of the ocean decreases, more CO2 will remain on the surface.This will feed back into global warming.

Ice loss in Antarctica is expected to continue or even accelerate as the planet warms. “It is almost certain that we will pass the 1.5°C global warming threshold by 2027”Indicate the signatories of the work.

More ice loss will mean more cooling and less mixing of surface water. Therefore, this trend will slow down and its consequences will become more intense.

And, as researchers insist, “The consequences of the slowdown will not be limited to Antarctica”. The overturned circulation extends across the global ocean, and such a collapse would worsen the climate crisis.

Connection: https://www.nature.com/articles/s41558-023-01667-8

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Contact address of the environmental department:krisclimatica@prensaiberica.es