AMOC Behavior During the Last Ice Age Supports Warnings of Future Weakening

Nature, 21 January 2026

New evidence confirms that the powerful North Atlantic system of ocean currents known as the AMOC (Atlantic Meridional Overturning Circulation) kept running during the last Ice Age, despite extreme cold and extensive ice cover. Today’s models accurately predicted this past behavior, which strengthens indications these models also are on the right track in projecting the AMOC’s future. Fossil data from the North Atlantic found that deep water critical for sustaining these major currents was only 1.8°C colder than today and flowed at sufficient depths during the Ice Age, demonstrating key components of healthy circulation. Chemical tracers similarly linked these deep waters to warm, salty surface waters from the subtropics and Nordic seas, confirming large-scale circulation rather than a weakened or shut-down system. These observations match the findings of current climate models, strengthening their credibility and lending credence also to future predictions by these models: that continued fossil fuel emissions and resulting warming will weaken these currents in the future, significantly cooling Europe and North Africa and disrupting global weather patterns.

Paper | Summary by University College London