CliSAP successfully finished in 2018. Climate research continues in the Cluster of Excellence "CLICCS".

Sea Ice in the Arctic: When the Winter Maximum is a Minimum


This time of year, we should normally see a substantial rise in the amount of arctic sea ice. But the reality is quite different this year. This indicator of climate change was one of the central themes at the CliSAP Workshop on the Arctic and Permafrost.

Sea-ice has been clearly thinner in February 2016 compared to February 2015. Evident in these pictures based on data from the SMOS satellite.
Researchers gathered for a workshop to discuss this and other topics related to the Arctic and Permafrost.

Changes in the sea-ice cover on the Artic Ocean are an important indicator of climate change. The sea ice, which normally reaches its annual minimum in September and its maximum in March, has been shrinking for years. According to workshop organizer Prof. Lars Kaleschke: “The ice coverage is currently roughly 1.2 million square kilometers less than the long-term mean for this time of year. In other words, we’re missing an area of ice bigger as Germany and France put together” – a clear sign that the growth in sea ice fell far below the average for the winter months.

In order to accurately measure the size, the movement and especially the thickness of the sea ice, the oceanographer and his team constantly work to refine the methods they use. Together with colleagues from the AWI in Bremerhaven, the team recently developed a new product that combines data from the ESA satellite programs CryoSat-2 and SMOS, capitalizing on their respective strengths. The satellite CryoSat-2 records how far the ice protrudes from the ocean, allowing it to precisely measure thicker ice, whereas SMOS relies on microwave radiation from the ice’s interior, making it especially well suited to measuring thin ice (illustration). During the workshop, Dr. Stefan Hendricks from the AWI gave those in attendance a glimpse of how the new method works.

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Roughly 90 researchers gathered for the workshop at Universität Hamburg, including guests from Finland, Italy and the USA. In the course of the three days, the participants not only discussed remote sensing methods for measuring the thickness of sea ice; as classic fields of research at CliSAP, physical and biogeochemical interactions between the ocean, atmosphere and land in the Arctic were also central topics.

At this third installment of the workshop, the Social Sciences & Humanities Session represented a new addition. One important consideration was the Arctic’s unique geopolitical position. In his talk Golo Bartsch, an arctic expert at Germany’s Federal Ministry of Defence, focused on the longstanding cooperation between the five Arctic Ocean nations. He stressed that, though the military presence has grown somewhat, for the most part the cooperation is dominated by more peaceful tasks like rescue missions. In his presentation on international politics, Dr. Rasmus G. Bertelsen from the University of Tromsø pointed out how scientific collaboration could offer a diplomatic solution to address China’s growing influence in the Arctic.

The various discussions during the three-day event showed key trends in today’s research. In this regard, the fact that climate change is also impacting the Arctic wasn’t a matter of debate; researchers were more interested in exploring the extent to which the Arctic is shaping climate change. How exactly does the Arctic’s influence work? And what about the greenhouse gases released as the permafrost continues to thaw? These are some of the key questions arctic researchers will work to answer in the near future. 


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