Atlantic current weakening may upend Arctic and European climate, study warns

Century-old records reveal weakening of AMOC, with wide-ranging climate risks for Europe and the Arctic

A mysterious cold patch south of Greenland — long an outlier in a rapidly warming Atlantic — may be a warning sign of major climate disruption ahead. A new study links it to the steady weakening of a massive Atlantic Ocean current system that helps regulate weather across Europe, sea levels along the U.S. East Coast, and Arctic ice conditions. If the trend continues, scientists warn, it could trigger more extreme winters, shifting rainfall patterns and ecological upheaval across the North Atlantic region.

In a new study published June 20 in Communications Earth & Environment, researchers from the University of California, Riverside analyzed over 100 years of ocean temperature and salinity data. Their findings show that only climate models simulating a weakening AMOC can account for the cooling trend observed in the North Atlantic—casting doubt on recent models that had projected a stable or even strengthening current.

“We found the most likely answer is a weakening AMOC,” said climate scientist Wei Liu, who led the research with doctoral student Kai-Yuan Li. “Only those models get it right.”

The AMOC, which includes the Gulf Stream, transports warm, salty water northward and returns cooler water at depth. A slowdown means less heat reaches the subpolar North Atlantic, leading to fresher, colder surface waters—a pattern confirmed by the century-long records examined in the study.

The implications are far-reaching. A weaker AMOC can shift weather systems across Europe and North America, destabilize marine ecosystems and alter Arctic climate dynamics. It also raises concerns about the accuracy of climate models used to inform policy and infrastructure planning across the North Atlantic region.

“Our results suggest many models underestimate this shift,” Liu said. “That has real consequences for future projections, especially in regions close to the Arctic.”

While direct AMOC measurements only date back about 20 years, this study used indirect indicators to extend the timeline and found that the weakening trend has likely been underway since the early 20th century.

If greenhouse gas emissions continue to rise, scientists warn the AMOC could weaken further or reach a tipping point — triggering abrupt and potentially irreversible changes to the global climate.

The waters south of Greenland, once seen as a local anomaly, may now be a key indicator of deeper climate disruption already in motion.