Scientific research has warned that the Gulf Stream system of warm ocean currents might collapse as early as 2025.
The failure of the system, which drives the Atlantic currents and governs the weather in Western Europe, would almost certainly result in lower temperatures and devastating climatic repercussions.
However, top experts have qualms about the study, claiming that it is not based on proven science.
They claim it is far from guaranteed that the system will be shut down this century.
The Intergovernmental Panel on Climate Change’s most recent assessment indicated that the system, known as the Atlantic Meridional Overturning Circulation (Amoc), will not collapse as soon as the research projected.
Prof Peter Ditlevsen of the University of Copenhagen, the study’s author, told BBC News that other experts have warned of the Amoc’s probable collapse.
“There’s been worries that this current is weakening for as long as we have had measurements of it – since 2004,” he added.
The Amoc is a complex network of currents that transports warm water north to the pole, where it cools and sinks.
However, as global temperatures rise due to global warming, new water from the melting Greenland ice cap and other sources is flooding into the Amoc.
If it fails, temperatures in Europe might drop by much to 10 degrees Celsius and sea levels in the eastern United States could rise. It would also interrupt rain, on which billions of people rely for agriculture.
Amoc halted and began around 115,000 to 12,000 years ago during the Ice Ages.
The latest study, published in Nature Communications, examined the variation in intensity of Amoc currents across time using sea surface temperature data dating back to 1870.
It predicts that Amoc will go bankrupt between 2025 and 2095.
The research assumes that greenhouse gas emissions will continue to rise in the same manner as they have in the past. If emissions began to fall, the globe would have more time to maintain temperatures below the point when Amoc may likely collapse.
However, scientists including Ben Booth of the Met Office Hadley Centre believe the paper’s findings are “far from settled science.”
“We just don’t have the evidence to state that it has declined,” says National Oceanography Centre Prof Penny Holliday.
“We know that there is a possibility that Amoc could stop what it’s doing now at some point, but it’s really hard to have certainty about that,” she adds.
“If my neighbour asked me if I should worry about heat waves or the Amoc collapse, I’d say worry about temperatures. We know that is already happening and will get worse,” she explained.
Many scientists are sceptical since the study’s authors made a number of assumptions regarding how to interpret Amoc.
However, the climate system is exceedingly complicated, and specialists lack all of the evidence required to completely comprehend the Amoc.
Predictions that it may collapse as early as 2025 or as late as 2095 should be taken with a grain of salt, according to Jon Robson of the National Centre for Atmospheric Science at the University of Reading.
However, they argue that this does not diminish the significance of the study or rule out the likelihood of Amoc’s closure.
“We do still have to take the idea seriously that there could be abrupt changes in the North Atlantic climate system,” Prof Robson adds.
“But the exact predictions that it will happen – and within this time frame – you have to take that with some scepticism,” he says.