The Subpolar North Atlantic (SPNA) is known for its rapid reversals in decadal temperature trends. This study combines datasets from ocean observing systems, idealized observation-based modeling, and a machine learning technique to document and explain the recent cooling-to-warming transition in the SPNA. Following a gradual cooling since 2006, a surface-intensified warming emerged in 2016 due to a shift in ocean circulation enhancing the northeastward penetration of warm, saline waters from the western subtropics. This advection-driven warming is likely to persist, impacting Atlantic multidecadal variability and global climate.

Damien Desbruyères, Léon Chafik, Guillaume Maze