Overview
- Scientists used instrument- and satellite-based climate reanalyses to show the North Atlantic cooling extends beneath the surface to roughly 1,000 metres and that surface heat loss in the region has fallen since the mid-1990s.
- Lead authors interpret these subsurface and surface patterns as a sign the Atlantic Meridional Overturning Circulation (AMOC) is weakening because the anomaly matches reduced poleward ocean heat transport.
- Independent experts welcomed the stronger observational evidence but said the result does not settle causation because atmospheric drivers and data gaps remain viable alternative explanations.
- A substantial AMOC slowdown could change weather and sea level regionally by cooling Northern Europe, altering monsoons in Africa and Asia, and raising U.S. East Coast sea levels, with direct effects for farmers, coastal communities, and fisheries.
- Long-term certainty is limited by short direct AMOC records and model differences, though multiple studies have suggested a longer-term decline in the circulation that makes further monitoring and research a priority.