After all, the rapid melting of Antarctica may not be as bad as people think

The melting of Greenland is expected to slow down the Atlantic Meridional Return Circulation. However, a new study suggests that a collapse of the West Antarctic Ice Sheet could, in some cases, preserve it.

While the melting of the Greenland ice sheet is expected to slow or even collapse the Atlantic Ocean current that keeps Europe warm, the West Antarctic meltwater could preserve this vital stream.

This is the conclusion of a study last Friday in Science Advances.

“I would tend to say: don’t be so quick to say that AMOC is going to collapse,” said the leader of the investigation, sacha sinetfrom the University of Utrecht, in the Netherlands, at .

The Atlantic Meridional Return Circulation (AMOC) is a system of currents that brings warm surface water from the tropics to northern Europe, where it cools and sinks before flowing south to Antarctica.

Light, fresh meltwater from the Greenland ice is expected to make it harder for the dense, salty water from the AMOC to sink, slowing the current.

If the AMOC were to collapse, winter cold snaps could reach almost -50°C in northern Europe. Sea levels would also be higher along the US east coast, and Africa could experience more severe droughts. Etc..

Scientists appeal for calm

In fact, melting of the West Antarctic Ice Sheet has been accelerating in recent decades, and some research suggests it is likely to collapse completely. However, the effect this will have on AMOC is uncertain.

According to simulations in the new study, the timing of the merger is crucial. If a centuries-long pulse of Antarctic meltwater arrives at the same time as a massive Greenland meltdown, it will only accelerate the shutdown of the AMOC.

If Antarctic water arrives about 1000 years before the peak of Greenland melting, however, the AMOC would weaken for several hundred years, but then would recover over the next 3000 years.

“I don’t think we knew until this study that there was this possibility that changes in Antarctica could potentially alter the impacts of melting the Greenland ice sheet so much. [na AMOC]”, tells New Scientist, Louise Simefrom the British Antarctic Survey, who was not part of the investigation.

However, even if drastic melting of West Antarctica prevented AMOC from collapsing, it would still cause up to 3 meters of sea level rise, flooding coastal cities.

“Unfortunately, it’s no consolation if one catastrophe can perhaps reduce the risk of another catastrophe”, he told the same magazine, Stefan Rahmstorffrom the University of Potsdam, Germany.