Atlantic currents that regulate weather could be grinding to a halt: study
Parts of the Atlantic Ocean may be grinding to a halt.
That is, a key system of currents that includes the Gulf Stream — which regulates much of the weather in the Northern Hemisphere — has destabilized to the point where it could collapse entirely in the future, a new study suggests.
It’s called the Atlantic Meridional Overturning Circulation, and it helps balance the energy in the Atlantic Ocean. The current system, which includes the Gulf Stream, carries warm surface water from the tropics to the north Atlantic, which sends the colder, saltier water sinking and flowing south.
The study published in Nature Climate Change, looked at more than a century of data on the ocean’s temperature and salinity to point to major changes in the circulation’s strength.
“The Atlantic Meridional Overturning really is one of our planet’s key circulation systems,” study author Niklas Boers from the Potsdam Institute for Climate Impact Research, Freie Universität Berlin and Exeter University said in a statement.
He added that computer simulations and data from Earth’s past have shown previous, weaker versions of the current, proving that it can indeed slow or stop, perhaps even abruptly.
“The difference is crucial”, Boers said, “because the loss of dynamical stability would imply that the AMOC has approached its critical threshold, beyond which a substantial and in practice likely irreversible transition to the weak mode could occur.”
A circulation shutdown could mean extreme cold for Europe and parts of North America and elevated sea levels along the U.S. East Coast, among other changes.
“This is an increase in understanding … of how close to a tipping point the AMOC might already be,” Levke Caesar, a climate physicist at Maynooth University who was not involved in the study, told The Washington Post.
There are many tipping points on the horizon that humankind has almost met with its activity, and any one of them could trigger change catastrophic enough to make Earth uninhabitable – and there’s no place else to go, as experts have warned time and again.
“The signs of destabilization being visible already is something that I wouldn’t have expected and that I find scary,” Boers told The Guardian. “It’s something you just can’t [allow to] happen.”
Besides the potential collapse of the Gulf Stream is the wobbling Greenland ice sheet that could feed sea level; the Amazon rainforest’s emitting more carbon dioxide than it absorbs, and a disconcerting level of methane that was released during a heat wave in Siberia in 2020, as The Guardian noted.
The Atlantic-currents study came out just before the United Nations Intergovernmental Panel on Climate Change issued its report on Monday, calling a “code red” for global warming.
“It’s just guaranteed that it’s going to get worse,” said report co-author Linda Mearns, a senior climate scientist at the U.S. National Center for Atmospheric Research, of climate change if we don’t change emissions and other behavior. “Nowhere to run, nowhere to hide.”
