North Atlantic sea surface temperatures significantly impact Northern Hemisphere weather. While the North Atlantic is warming due to greenhouse gases, climate projections show a surprising cooling region at mid-latitudes—the North Atlantic warming hole. This study analyzes climate models and observations to determine if this cooling is anthropogenic or due to internal climate variability. The results indicate the warming hole is anthropogenic, recently emerging from internal variability and attributable to greenhouse gas emissions. A declining northward oceanic heat flux, linked to this pattern, is also found to be anthropogenic.

Rei Chemke, Laure Zanna, Lorenzo M. Polvani