North Atlantic ocean currents and heatwaves face potential instability

Scientists are investigating the stability of the Atlantic Meridional Overturning Circulation (AMOC), a vast system of ocean currents that transports warm water northward. This circulation is critical for maintaining milder climates in the UK and northwestern Europe. Researchers have identified concerning signs of potential destabilization, including cooling anomalies in the North Atlantic and changes in water salinity. A significant weakening or collapse of the AMOC could shift storm patterns, alter rainfall, and lead to colder, drier winters in Europe, while also impacting global monsoon patterns and tropical rainfall.

Parallel research from the University of Bern indicates that marine heatwaves in the North Atlantic could be significantly more extreme than currently observed. Simulations suggest that under certain atmospheric conditions, the 2023 heatwave could have lasted up to 579 days with temperatures reaching 4.5 degrees Celsius above the long-term average. Such extreme temperatures threaten marine life, promote harmful algal blooms, and disrupt fisheries. High-pressure systems, weak winds, and intense solar radiation are identified as key drivers that allow heat to accumulate at the ocean surface.