Atlantic current could regain strength if warming reverses

The Atlantic’s Amoc system of ocean currents could regain strength if global warming is reversed, according to a study by the Danish Meteorological Institute (DMI), reported by DR.

Researchers found no tipping point leading to an irreversible collapse in the model they studied. Instead, Amoc weakened gradually and regained strength when warming was reversed. The study’s lead author, DMI climate researcher Chuncheng Guo, said the system is often described in overly stark terms, when the picture is more nuanced.

The researchers cautioned that their findings are based on one model, and more models are needed to assess how robust the conclusion is. In their simulation, the cooling needed to restore Amoc happened at a rate beyond what current technology is considered capable of achieving. How quickly recovery could occur in practice remains uncertain, Guo said.

In the model, Amoc’s flow fell from about 17 million cubic metres of water per second to around six million as global temperatures rose by about seven degrees. The current carries warm tropical water north towards Europe and the Arctic, where it cools and sinks before flowing south again.

Amoc is a central part of the global climate system and is already at its weakest level in 1,600 years, according to the article. A collapse could shift the tropical rainfall belt, which millions of people rely on for growing crops, bring extreme winters and summer drought to western Europe, and raise sea levels around the Atlantic by between half a metre and one metre.