Freshening of the Barents Sea during the recent decade and its impact on the outflow of dense waters

Dense water formed in the shallow Barents Sea feeds the deep branch of the Atlantic Meridional Overturning Circulation and is therefore an important part of the global climate system. The properties of dense waters in the Barents Sea are sensitive to the temperature and salinity of Atlantic Water (AW) advected into the region, as well as to the interaction with sea ice. Here, using a suite of satellite, reanalysis and in situ data for the time-period 1991–2024, we investigate the drivers of the interannual variability and recent changes in the hydrographic properties of the dense waters exiting the Barents Sea. Statistical analysis of the data shows that the freshening in the southern Barents Sea during the recent years, is primarily associated with decreased salinity of the inflowing AW. In contrast, freshening in the northern Barents Sea reflects the combined influence of fresher AW and enhanced import of sea ice from the central Arctic, driven by changes in atmospheric circulation, which temporarily halted the long-term Atlantification trend. The combination of reduced salinity and persistently warm conditions produced the lowest density of dense waters exiting the Barents Sea in the last three decades, with implications for downstream overturning circulation.