Regime Shift in a Warming Climate—Emerging Barents Oscillation and its Dominance in Eurasian Cold Extremes

In recent decades, Eurasia has experienced a substantial increase in cold extremes. While the North Atlantic Oscillation (NAO) is well established as a modulater of Eurasian cold extremes, we uncovered a previously overlooked, yet increasingly critical, driver in a warming climate—the Barents Oscillation (BO). With accelerated Arctic warming, the BO has emerged as a dominant atmospheric circulation pattern. This intensified BO accounts for 59% of the observed severe cold extremes across Eurasia. In the future during 2015−2100, the BO is projected to intensify across SSP scenarios, with its increasing rate in SSP5-8.5 doubling that of SSP1-2.6. The enhanced BO is expected to exacerbate cold extremes by approximately −0.5°C for each standard deviation increase in the BO intensity. These findings emphasize the BO’s growing importance in amplifying Eurasian cold extremes under global warming, challenging the prevailing NAO-centric framework.