Marine Heatwaves in the Arctic - A Silent Climate Emergency?

27 December 2024

Photo: UHH/Dalena León-FonFay

A marine heatwave with an intensity so rare it used to occur only once every 100 years is expected to become a once-in-seven-years event in a 2°C warmer world. One in 4 Arctic summer months will break today’s heat records, accelerating ice melt and disrupting ecosystems. In a 2 °C world, non-linear intensification of events is projected to occur by 2042, primarily driven by rising ocean temperature. The findings highlight that even a half-degree of global warming can dramatically intensify extremes in this fragile region. This striking insight comes from a recent study by Dalena León-FonFay, Armineh Barkhordarian and colleagues that utilize the 50-member MPI-ESM-LR Earth System model and examine the sensitivity of Arctic marine heatwaves to half-a-degree increase in global warming, from 1.5 °C to 2 °C, with respect to pre-industrial levels.

Dalena León-FonFay et al. “Sensitivity of Arctic marine heatwaves to half-a-degree increase in global warming: 10-fold frequency increase and 15-fold extreme intensity likelihood”, Environ. Res. Lett. 20 014049, 2025, DOI: https://doi.org/10.1088/1748-9326/ada029