Ocean-atmosphere coupling enhances Eurasian cooling in response to historical Barents-Kara sea-ice loss

Abstract

The potential for Arctic sea-ice loss, particularly in the Barents-Kara Seas, to induce Eurasian winter cooling remains contentious. Despite a significant correlation between Barents-Kara-Seas sea-ice loss and Eurasian winter cooling in observations, modeling studies suggest minimal causal influence. Through constraining Barents-Kara-Seas sea-ice to different states in ocean-atmosphere-coupled simulations, here we show that ocean-atmosphere coupling enhances the Eurasian cooling induced by historical sea-ice loss, though still weaker than observed, likely due to internal variability and confounding factors. Historical sea-ice loss induces stronger and deeper Arctic warming with ocean-atmosphere coupling than without, associated with a strengthened Siberian High and East Asian Trough, which promotes Eurasian cooling. However, ocean-atmosphere coupling has little influence on the Eurasian cooling response to projected end-of-the-twenty-first-century sea-ice loss. The Eurasian temperature response to historical sea-ice loss is dominated by dynamically-induced cooling, whereas strong thermodynamical warming masks dynamically-induced cooling in response to far-future sea-ice loss.