Atlantic Ocean Circulation Shows Signs of Weakening, Study Finds

The continents may become a single landmass-or "supercontinent"-and the ocean would close.
Map courtesy Reto Stöckli, NASA Earth Observatory, via National Geographic

The Atlantic Meridional Overturning Circulation (AMOC) is one of the planet’s most important ocean currents, acting like a giant conveyor belt that moves warm water from the tropics toward the North Atlantic. This system helps regulate global climate, stabilizes weather patterns, and even affects sea levels. Recent research, however, shows that the AMOC is showing signs of weakening , a trend closely linked to human activity and overconsumption.

A 2025 study by McCarthy et al. (Geophysical Research Letters) analyzed data from 2004 to 2023 at 26° N in the Atlantic. The researchers found that the AMOC has slowed by about 1.0 Sverdrup per decade. While this may seem small, ocean currents operate on massive scales, and even subtle changes can ripple across ecosystems and societies. The study also highlights that natural variability makes it hard to immediately see the long-term trends, meaning the full impact of this slowdown could become more apparent in the coming decades.

The weakening of the AMOC is tied to rising global temperatures and the melting of Greenland’s ice sheets, both consequences of industrial greenhouse gas emissions and unsustainable consumption patterns. If the current trajectory continues, we could see more extreme weather, disruptions to agriculture, rising sea levels, and changes to marine ecosystems.

References:
Caesar, L., McCarthy, G. D., Thornalley, D. J. R., Cahill, N., & Rahmstorf, S. (2021). Current Atlantic Meridional Overturning Circulation weakest in last millennium. Nature Geoscience, 14(7), 118-120. https://doi.org/10.1038/s41561-021-00699-z

McCarthy, G. D., Frajka-Williams, E., Meinen, C. S., & Kanzow, T. (2025). Signal and noise in the Atlantic Meridional Overturning Circulation at 26°N. Geophysical Research Letters, 52(7), e2025GL115055. https://doi.org/10.1029/2025GL115055