Future increases in Eurasian mid-latitude winter temperature variability shaped by a weakened Atlantic Meridional Overturning Circulation

Climate models project reduced temperature variability in Northern high latitudes due to global warming, but impacts on mid-latitude variability remain uncertain. Here, using multi-model simulations from the Coupled Model Intercomparison Project, we find that daily winter temperature variability increases across the Eurasian mid-latitudes under future warming. This variability strongly correlates with the North Atlantic sea surface temperature gradient, characterized by a warm tropics–cold high-latitude sea surface temperature pattern linked to a weakened Atlantic Meridional Overturning Circulation. Idealized simulations using a climate model confirm that a stronger North Atlantic Sea surface temperature gradient amplifies Eurasian mid-latitude temperature variability by enhancing the meridional temperature gradient. Additional simulations show that warming in the tropical Indian Ocean-western Pacific warm pool has a weaker effect on Eurasian temperature variability than the North Atlantic sea surface temperature gradient. These findings suggest that Atlantic Meridional Overturning Circulation weakening could lead to heightened winter variability in Eurasian mid-latitudes. Winter temperature variability in the Eurasian mid-latitudes is projected to increase under future warming and be modulated by the degree of Atlantic Meridional Overturning Circulation weakening, according to the Coupled Model Intercomparison Project and idealized model experiments.