Work

Enhanced Decadal Variance in Nordic Seas With AMOC Weakening in CESM

Year: 2026

Type: article

Abstract: The subpolar North Atlantic (SPNA) exhibits rapid, decadal‐scale cooling events in several climate model projections, but the mechanisms behind this variability, particularly the role of a weakening Atlantic Meridional Overturning Circulation (AMOC), remain uncertain. Here we analyze model output from a quasi‐equilibrium hosing experiment using the Community Earth System Model version 1 (CESM1) to assess SPNA variability under a gradually declining AMOC. During a 600‐year period preceding an AMOC collapse, the overturning strength weakens by ∼15% and decadal surface temperature variance in the Nordic Seas increases eightfold. Statistical analysis links this enhanced variability to feedbacks between ocean convection, salinity, and sea‐ice, which strengthen under cooler background conditions associated with reduced AMOC strength. Our results suggest that even modest AMOC weakening is associated with substantially enhanced SPNA variability, pointing to increased regional climate variability under AMOC decline and to potential early warning indicators of AMOC collapse.

Source: Geophysical Research Letters

DOI: 10.1029/2025gl118635

Authors: Casey R. Patrizio, Henk A. Dijkstra, Anna S. von der Heydt, Robbin Bastiaansen

Institution: Utrecht University

Language: English

Topic: Climate variability and models

Subfield: Global and Planetary Change

Field: Environmental Science

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,190