A giant Atlantic Ocean current that helps regulate Earth’s climate is slowing down, and scientists say the impacts could be global.
A massive Atlantic Ocean circulation system that plays a central role in regulating Earth’s climate has been weakening for nearly 20 years, according to a new study. Scientists say the slowdown spans a large portion of the Atlantic and could eventually alter weather patterns in many parts of the world.
The research, led by scientists at the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science, provides some of the strongest direct observational evidence so far that the Atlantic Meridional Overturning Circulation (AMOC) is losing strength. Researchers say the findings could improve climate forecasts and help scientists better understand how global warming may affect future weather and ocean conditions.
“A weaker AMOC can shift weather patterns, potentially leading to more extreme storms, changes in rainfall, or colder winters in some regions,” said Shane Elipot, a senior author of the study and physical oceanographer at the Rosenstiel School. “It can also influence sea-level rise along coastlines, affecting communities and infrastructure.”
Deep Ocean Monitoring Reveals Long-Term Trend
To study the current system, researchers examined long-running observations collected from four ocean monitoring arrays positioned along the western side of the North Atlantic, stretching from tropical waters into higher latitudes.
The instruments, anchored to the seafloor, continuously measured pressure, temperature, density, and ocean currents. Scientists used the same analysis method at every site—using changes in bottom pressure to estimate deep ocean flow below about 1,000 meters. By comparing the data across locations and over long periods of time, the team identified a sustained decline in the strength of the overturning circulation.
Measurements from several latitudes revealed a steady weakening in an important section of the AMOC along the Atlantic’s western boundary, extending from the subtropics to mid-latitudes (about 16.5°N to 42.5°N). Because the trend appeared across such a broad region, researchers say it points to a large-scale shift rather than a temporary fluctuation.
Why the AMOC Matters for Global Climate
The AMOC is one of the most important systems controlling climate in the Atlantic region. It helps distribute heat through the ocean, influencing temperatures, weather patterns, and sea levels, especially around the North Atlantic.
Scientists say a slowdown in the circulation could affect European winters, hurricane activity, rainfall patterns, and other climate conditions around the globe.
Researchers also believe measurements taken along the western boundary of the Atlantic may act as an early warning signal for future climate changes. They compared the monitoring approach to a canary in a coal mine because it may provide an efficient way to track long-term changes in this crucial climate-regulating system.
“This research helps scientists better predict how the climate may change in the coming decades—information that governments, businesses, and communities use to prepare for future environmental conditions,” said Elipot.
The study, titled “Meridionally consistent decline in the observed western boundary contribution to the Atlantic Meridional Overturning Circulation,” was published in the April 8 issue of Science Advances.
Reference: “Meridionally consistent decline in the observed western boundary contribution to the Atlantic Meridional Overturning Circulation” by Qianjiang Xing, Shane Elipot, William E. Johns, David A. Smeed, Ben I. Moat and John W. Loder, 8 April 2026, Science Advances.
DOI: 10.1126/sciadv.adz7738
Funding for the research came from the U.S. National Science Foundation (OCE-2148723 and OCE-2334091) and the UK Natural Environment Research Council grants (NE/Y003551/1 and NE/Y005589/1).
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