A Prospective Cooling Machine for the Svalbard Branch of Norwegian Atlantic Water in a Future Climate

Abstract

The evolution of air‐sea interaction and the ocean north of Svalbard is investigated using a high‐resolution configuration of the coupled climate model HadGEM3‐GC3.1 under a high‐emission pathway (SSP5‐8.5). To the west and north of Svalbard, where the West Spitsbergen Current—the northward branch of the Norwegian Atlantic Current—carries warm and saline Atlantic Water (AW) into the Arctic, we identify a significant shift in the pattern of sea‐ice decline. In the late 20th century, the sea‐ice edge retreats gradually downstream along the current's pathway. However, in the 21st century, the ice edge retreats northward across the continental slope, leading to the simultaneous exposure of the AW core to the atmosphere. This rapid increased exposure triggers enhanced cooling and convective mixing along the AW pathway. The water column undergoes destratification due to the AW encroachment, along with mixing, resulting in a warmer and less stratified upper ocean downstream on this pathway. The potential temperature maximum of the AW shoals, increasing the potential for enhanced oceanic heat loss. A closed regional ocean heat content analysis reveals that net advective heat convergence into the region increases substantially, driving a sustained wintertime surface heat loss that stabilizes at ∼70 TW by the 2040 s. These changes suggest that a prospective “cooling machine” north of Svalbard will soon emerge in a future climate, operating at a capacity comparable to the Barents Sea and fundamentally altering the water mass transformation and heat export into the deep Arctic interior.