Arctic marine heatwaves are intensifying, with marginal seas warming 0.6°C/decade—twice the global rate—and lasting 10-40 days, a new study reveals. Driven by sea ice loss and deep Atlantic currents, freshwater layers from melting ice amplify and prolong these surface heatwaves by 20%.

Arctic marine heatwaves are intensifying, with marginal seas warming 0.6°C/decade—twice the global rate—and lasting 10-40 days, a new study reveals. Driven by sea ice loss and deep Atlantic currents, freshwater layers from melting ice amplify and prolong these surface heatwaves by 20%.