Abstract
The Beaufort Gyre is an important feature of the Arctic Ocean. By
accumulating or releasing freshwater, it influences ocean properties
both within the Arctic and as far as the North Atlantic. Yet, its future
remains uncertain: the gyre could strengthen as sea ice declines and
allows increased wind stress on the ocean, or weaken along with the
Beaufort High pressure system. Here, we provide a first evaluation of
the Beaufort Gyre in historical and climate-change simulations from 27
available global climate models. We find that the vast majority of
models overestimate the gyre area, strength, and northward extent. After
discarding the models with too inaccurate a gyre and its drivers –
namely, the sea ice cover and Beaufort High – we quantify changes in
the Beaufort Gyre under two emission scenarios: the intermediate
SSP2–4.5 and the high-warming SSP5–8.5. By the end of the 21st
century, most models simulate a significant decline or even
disappearance of the Beaufort Gyre, especially under SSP5–8.5. We show
that this decline is mainly driven by a simulated future weakening of
the Beaufort High, whose influence on the Beaufort Gyre variations is
enhanced by the transition to a thin-ice Arctic. The simulated gyre
decline is associated with an expected decrease in freshwater storage,
with reduced salinity contrasts between the gyre and both Arctic
subsurface waters and freshwater outflow regions. While model biases and
unresolved processes remain, such possible stratification changes could
shift the Atlantic-Arctic Meridional Overturning Circulation northward.