Plate Nº 49 · recorded October 10, 2026
Earth & ClimateReported finding
Atlantic's Climate-Regulating Current Has Weakened for 20 Years
Researchers tracking four seafloor arrays find the AMOC's western boundary contribution has declined consistently from 16.5°N to 42.5°N over nearly 20 years.
By Nathan Brooks3 min read614 words
In brief
- A key component of the AMOC has declined consistently from about 16.5°N to 42.5°N over nearly 20 years, according to data from four seafloor monitoring arrays.
- The study was published April 8 in Science Advances by researchers at the University of Miami Rosenstiel School, with senior author Shane Elipot.
- Researchers used bottom-pressure measurements below about 1,000 meters to estimate deep-water movement along the western boundary of the North Atlantic.
- The work was funded by U.S. National Science Foundation grants OCE-2148723 and OCE-2334091 and UK NERC grants NE/Y003551/1 and NE/Y005589/1.
- Co-authors include Qianjiang Xing, William E. Johns, David A. Smeed, Ben I. Moat, and John W. Loder; DOI: 10.1126/sciadv.adz7738.
The Atlantic's climate-regulating circulation has weakened consistently across a 26-degree span of the North Atlantic for nearly 20 years, according to a study published April 8 in Science Advances.
Researchers at the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science analyzed pressure, temperature, and current data from four seafloor monitoring arrays along the western edge of the basin. The team documented a sustained slowdown in a major component of the Atlantic Meridional Overturning Circulation, known as AMOC, from about 16.5°N to 42.5°N.
What is the AMOC and why does it matter?
The AMOC is a conveyor-belt-like system that carries warm surface water northward and returns colder, denser water southward at depth. By redistributing heat across the Atlantic, the system shapes temperatures, rainfall, storm activity, and sea level from the tropics to higher latitudes.
"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 physical oceanographer at the Rosenstiel School and senior author of the study. "It can also influence sea-level rise along coastlines, affecting communities and infrastructure."
How did researchers measure the slowdown?
The team drew on long-term records from instruments anchored to the seafloor. The arrays continuously log pressure, temperature, density, and current speed along the western boundary. By examining bottom pressure below about 1,000 meters, the researchers estimated the southward movement of deep water.
They applied the same analytical method to all four arrays, which let them separate long-term trends from natural year-to-year swings in ocean circulation. Multi-decadal records matter because currents can fluctuate for years before any persistent shift becomes statistically clear.
What did the data show?
Pressure records at multiple latitudes traced a similar decline. The study, titled "Meridionally consistent decline in the observed western boundary contribution to the Atlantic Meridional Overturning Circulation," provides some of the clearest direct observational evidence so far that the AMOC's western boundary contribution has lost strength.
The consistency across latitudes is the key finding. A persistent decline across such a wide swath of ocean fits a basin-wide shift in Atlantic circulation better than a short-lived regional fluctuation, the authors argue.
Could the western Atlantic serve as an early warning?
The authors compare the western boundary to a canary in a coal mine: because changes there appear coherent across many latitudes, measurements in that region may offer a relatively efficient way to detect broader shifts in the climate-regulating circulation.
"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," Elipot said.
What are the study's limits and what comes next?
Twenty years is long enough to reveal a consistent trend but short compared with the multi-century records scientists use to characterize the AMOC. The new analysis focuses on the western boundary, so it captures only one slice of a basin-wide system.
Researchers still do not know whether the current slowdown reflects temporary variability or the leading edge of a longer decline. Earlier model-based studies have projected substantial weakening this century, but observational confirmation has lagged.
The study received funding from the U.S. National Science Foundation (grants OCE-2148723 and OCE-2334091) and the UK Natural Environment Research Council (grants NE/Y003551/1 and NE/Y005589/1). Authors include Qianjiang Xing, Shane Elipot, William E. Johns, David A. Smeed, Ben I. Moat, and John W. Loder. The paper appeared in the April 8 issue of Science Advances; the DOI is 10.1126/sciadv.adz7738.
via news.miami.edu (Original)
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