High-resolution modelling identifies the Bering Strait’s role in amplified Arctic warming
The Bering Strait is a narrow and shallow passage that connects the North Pacific Ocean with the Arctic. Roughly 1 million m3 of water passes through the Bering Strait every second, carrying relatively warm waters into the Arctic Ocean. In this paper, we show that this heat transport is projected to increase in a warming climate and that it contributes significantly to 21st-century Arctic warming. This effect is not properly captured in the current generation of climate models, whose resolution is too low to properly represent the flow through this narrow channel.
Ocean heat transport into the Arctic Ocean is an important driver of the rapidly accelerating warming of the Arctic Earth system (Arctic Amplification). Most of the attention has been given to the Atlantic side, where warm Atlantic waters are known to enter the Arctic Ocean through the Barents Sea Opening and the Fram Strait. This paper highlights the importance of oceanic heat transport on the Pacific side as a major driver of Arctic warming, which has not previously been recognized.
The Arctic region has warmed nearly four times faster than the global average since 1979, with far-reaching global implications. However, model projections of Arctic warming rates are uncertain, and one key component is the ocean heat transport (OHT) into the Arctic Ocean. Here we use high-resolution historical and future climate simulations to show that the OHT through the Bering Strait exerts a more substantial influence on Arctic warming than previously recognized. The high-resolution ensemble exhibits a 20% larger warming rate for 2006–2100 compared with standard low-resolution model simulations. The enhanced Arctic warming in the high-resolution simulations is primarily attributable to an increased OHT through the narrow and shallow Bering Strait that is nearly four times larger than in the low-resolution simulations. Consequently, the projected rate of Arctic warming by low-resolution climate simulations is likely to be underestimated due to the model resolution being insufficient to capture future changes in Bering Strait OHT.