A recent study released on Tuesday warns that the Gulf Stream, an Atlantic Ocean current responsible for keeping Europe warm, could suddenly and catastrophically halt at any point in the next few decades.
According to a study published in Nature Communications by Peter Ditlevsen and Susanne Ditlevsen from the University of Copenhagen, the Atlantic Meridional Overturning Circulation (AMOC) is predicted to collapse due to future emissions. This could happen around mid-century, potentially as early as 2025 or as late as 2095.
Other scientists urged caution in interpreting the findings, though.
Niklas Boers of the Technical University of Munich said the modeling was “heavily oversimplified.” The authors of Tuesday’s study admitted they made uncertain assumptions.
AMOC pushes warm water north along the Gulf Stream. As a result, England, which is at the same latitude as Canada, is much warmer.
Its sudden end is a long-standing climate change prediction, but scientists have deep divisions about whether and when it could happen. There is no disagreement about the consequences if a collapse were to happen.
“A collapse of the AMOC would be disastrous,” said Jonathan Bamber, director of the Bristol Glaciology Centre, who was not involved in the study.
He warned that other “plausible” assumptions in the modeling than those used in the study would lead to “a different conclusion.”
This July will likely be recorded as the hottest month ever. The release of greenhouse gas emissions from burning fossil fuels is causing fresh, cold water to melt off the Greenland ice sheets, resulting in a hard patch in the warming ocean of the North Atlantic. This has caused a slowdown of the currents that regulate the seas along the European and North American Atlantic coastlines, as noted in the Ditlevsens’ study.
“This is indeed a worrisome result, which should call for fast and effective measures to reduce global greenhouse gas emissions,” said the pair.
However, the U.N.’s Intergovernmental Panel on Climate Change (IPCC) recently found the current was unlikely to stop this century suddenly.
“The work provides no reason to change the assessment of the [IPCC],” said Jochem Marotzke of the Max-Planck-Institute for Meteorology in Hamburg.
If the current were to switch off, said Penny Holliday, head of marine physics and ocean circulation at the U.K.’s National Oceanography Center, it would transform the global climate.
Many areas would feel freezing temperatures if a cooling event affected the Northern Hemisphere. Sea ice would move southward from the North Pole towards Europe, and rainfall patterns across the globe would be impacted, resulting in droughts in some continents and heavy precipitation in others.
“This would dramatically change every nation’s ability to provide enough food and water for its population,” said Holliday.
Although some scientists may not believe in an abrupt collapse, there is a consensus that the current is becoming increasingly unpredictable. This could lead to unanticipated effects, such as more severe winter storms in Britain or more extreme heat waves in Europe, according to Levke Caesar of the University of Bremen.
“There is a large number of people who would be affected by a weaker AMOC,” said Caesar.