Overview
- New analyses of mooring arrays report a coherent slowdown of the Atlantic Meridional Overturning Circulation at the ocean’s western boundary across several North Atlantic latitudes.
- RAPID‑MOCHA data indicate the flow has declined by roughly 90,000 cubic metres per second each year, about a 10% drop from 2004 to 2023, though the estimate carries large uncertainty.
- Pressure records from three additional western‑Atlantic arrays off the West Indies, the US east coast, and Nova Scotia show an even stronger weakening with smaller uncertainty.
- Researchers say meltwater from Greenland is likely diluting salty surface waters and slowing the sinking that drives the deep southward limb of the circulation.
- A separate simulation study finds that an AMOC collapse would release carbon from the Southern Ocean and add 0.17°C to 0.27°C of global warming, with models indicating the system would not recover once off at CO₂ levels at or above 350 ppm.