Photo: Jonathan W. Rheinlænder
Photo: Jonathan W. Rheinlænder

Will a thinner ice cover mean increased sea-ice breakup in the Arctic?

In the past two decades, the sea-ice cover in the Beaufort Sea in the Arctic region has changed a lot. It used to be mainly thick and old ice, which was not very mobile. Nowadays, you find mostly seasonal ice which forms during the winter and melts during the summer.

This strong trend seen in the Beaufort region has implications for the evolution of the Arctic sea-ice cover, in turn affecting the regional and global climate. Researchers from the Nansen Center used the sea-ice model neXtSIM to investigate how these changes are tied to large breakup events in the sea-ice cover.

The idea behind this recently published study was inspired by a scientific workshop held last year at the Woods Hole Oceanographic Institution in the US. “The workshop intended to bring researchers together to discuss and share knowledge about the Beaufort Sea region, and to identity key knowledge gaps”, says lead author of the study Jonathan W. Rheinlænder. “A major unknown is how the transition to a thinner and younger ice cover is affecting sea-ice breakup during winter months and their wider implication for sea ice in the region. This inspired us to use our sea-ice model neXtSIM to study the link between sea-ice thinning and breakup events in the Beaufort region over the past 20 years.”

Rheinlænder and his colleagues at the Nansen Center discovered that the observed shift to thinner and younger sea ice goes hand in hand with an increase in breakup events and more openings in the winter ice pack. This has a negative impact on the amount of ice in the Beaufort Sea. Previously, it was believed that breakup events in winter had a positive impact on the regional ice volume by increasing the amount of new ice formed within openings in the ice pack. While this remains true, their findings now indicate that breakup events also result in a significant amount of sea ice being transported out of the region, leading to a net loss of ice compared to what is replenished by new ice formation. This results in a thinner and weaker sea ice cover by the end of winter. Starting the melt season with a thinner and weaker ice cover can lead to earlier breakup in spring and increase the melting during the summer, which may contribute to accelerated ice loss in the Beaufort Sea region.

Why is this relevant, you wonder? Climate change is affecting the entire globe, and especially the Arctic region. Meanwhile, changes in the Arctic sea-ice cover in turn can have impacts on the regional and global climate. Therefore, we want to be able to predict what will happen to the Arctic sea ice as accurately as possible. Being able to represent sea ice breakup in climate models is an important step to improve climate projections, thereby expanding our ability to address and mitigate climate change effectively.

The Beaufort Sea and sea ice

The Beaufort Sea lies in the Arctic, north of Alaska and the northwestern part of Canada, and south of the central Arctic Ocean. Before the turn of the millennium, the sea-ice cover was dominated by thick multi-year ice, whereas today the ice cover is much thinner and consists of mainly young ice. This seasonal ice cover is weaker and therefore easier to break apart.

Our sea-ice model neXtSIM

Pioneering research at the Nansen Center includes the development of an innovative sea-ice model called neXtSIM, which effectively simulates processes such as the formation of leads and ridges in sea ice. The model is used both for operational services and for more traditional research. Read more here.


Journal of Geophysical Research: Oceans

“Breaking the Ice: Exploring the Changing Dynamics of Winter Breakup Events in the Beaufort Sea”