Heat wars on the Barents front: how sea ice is pushed back by warmer waters

The cold, remote Arctic Ocean and its surrounding marginal seas have experienced climate change at a rate not seen at lower latitudes. Warming air, land and sea temperatures, and large declines in seasonal Arctic sea ice cover are all symptoms of the changing Arctic climate. Although these changes are occurring in relatively remote locations, there is growing evidence to link Arctic sea ice retreat to increasingly erratic weather patterns over the northern hemisphere.

Some regions in the Arctic Basin are already seasonally ice-free, and can thus be studied as test cases for what the Arctic might become in the future. This is for instance the case for the Barents Sea. The ocean dynamics in this region is complex, as warm water from the Atlantic penetrates all the way up into the Barents Sea, where it is strongly cooled by the very cold overlying atmosphere and its interaction with sea ice. Dense water resulting from these water mass transformations in the Barents Sea are eventually exported to the Arctic Ocean and then to the Nordic Seas, where it contributes to the dense overflow over the Greenland-Scotland ridge and the southward flowing limb of the Atlantic meridional overturning circulation (AMOC).

In a recent study published in JPO, led by Ben Barton (PhD student at LOPS), we have looked at satellite measurements of sea ice and sea surface temperature, as well as in situ measurements, in order to determine how ocean and ice conditions have evolved between 1985 and the end of 2016. We found that prior to 2005, sea ice extended over most of the Barents Sea every winter, but that since 2005 this has not been the case. Indeed, observations of sea surface temperature reveal a strong intensification of the Polar Front in the Barents Sea, resulting from the warming of both the Atlantic Water inflow and the atmosphere, and the front became a barrier that sea ice cannot breach anymore.

The full article can be read here: https://journals.ametsoc.org/doi/abs/10.1175/JPO-D-18-0003.1. An article describing the results has been published in ‘the Conversation’ (https://theconversation.com/extreme-weather-in-europe-linked-to-less-sea-ice-and-warming-in-the-barents-sea-100628). Or you can watch this one minute video featuring Ben describing his study.