Narwhals reveal warm Atlantic water deep in Greenland fjords

Researchers using sensors attached to six narwhals have discovered warm Atlantic water penetrating up to 186 miles into Greenland's fjords. The data, collected via narwhal dives between 2017 and 2020, revealed that warm, salty water is moving beneath colder surface layers and reaching toward glacier fronts in the Scoresby Sound fjord system.

This phenomenon is part of a broader Arctic trend known as ‘Atlantification,’ where warmer Atlantic-origin water increasingly affects regions previously protected by sea ice and colder water. Because these remote, ice-covered fjords are often inaccessible to research vessels, the narwhals provided unique access to deep-sea environments. The findings, published in Science Advances, suggest that this influx of heat can melt glaciers from underneath, contributing to ice loss.