Dense water masses from the Barents Sea are an important part of the Arctic thermohaline system. Here, using hydrographic observations from 1971 to 2018, we show that the Barents Sea climate system has reached a point where ‘the Barents Sea cooling machine’—warmer Atlantic inflow, less sea ice, more regional ocean heat loss—has changed towards less-efficient cooling. Present change is dominated by reduced ocean heat loss over the southern Barents Sea as a result of anomalous southerly winds. The outflows have accordingly become warmer. Outflow densities have nevertheless remained relatively unperturbed as increasing salinity appears to have compensated the warming inflow. However, as the upstream Atlantic Water is now observed to freshen while still relatively warm, we speculate that the Barents Sea within a few years may export water masses of record-low density to the adjacent basins and deep ocean circulation.

来自巴伦支海的密集水团是北极热盐系统的重要组成部分。在这里，使用1971年至2018年的水文观测资料，我们发现巴伦支海的气候系统已经达到了“巴伦支海冷却机”（更温暖的大西洋流入量，更少的海冰，更多的区域海洋热损失）已经转变为更少的温度。高效冷却。当前变化主要是由于南风异常导致巴伦支海南部海洋热量散失减少。因此，流出量变热。然而，由于盐度的增加似乎已经补偿了增温流入，因此流出密度仍然相对不受干扰。不过，由于现在观察到上游大西洋水在保持相对温暖的同时仍在变新鲜，