A study published in Science Advances in April 2026 found that what ocean current is likely to weaken by 42–58% by 2100?

The Atlantic Meridional Overturning Circulation, or AMOC, is a vast system of ocean currents that acts like a gigantic conveyor belt, moving warm, salty water northward near the surface of the Atlantic Ocean and returning colder, denser water southward at deeper levels. This continuous circulation plays a crucial role in regulating Earth's climate, particularly influencing temperatures and precipitation patterns in Europe, the Americas, and Africa. It's responsible for keeping northwestern Europe significantly warmer than other regions at similar latitudes.

A study published in Science Advances in April 2026 presented concerning findings regarding the future of the AMOC. By combining climate models with real-world observations of ocean temperature and salinity, scientists determined that the AMOC is likely to weaken by 42–58% by the year 2100. This projected slowdown is notably more substantial than previous estimates, indicating that the "pessimistic" climate models, which show a stronger weakening, are unfortunately the more realistic ones.

The primary driver of this weakening is the influx of freshwater into the North Atlantic, largely from melting glaciers in Greenland due to global warming. This freshwater reduces the salinity and thus the density of the surface water, inhibiting its ability to sink and disrupting the mechanism that powers the AMOC. Such a significant weakening could have far-reaching and severe consequences, including accentuated temperature differences between the Equator and the poles, a cooling of Europe, shifts in rain belts in southern Africa, and accelerated melting of Antarctica's ice sheets. It could also lead to regional sea level rise along the U.S. East Coast and reduce the ocean's capacity to absorb atmospheric carbon.