Into the melting Arctic ice

Profiles in Norwegian science

MOSAiC expedition and the Polarstern

Photo: Alfred-Wegener-Institut / Steffen Graupner
The German icebreaker Polarstern, home of the drifting research expedition MOSAiC, followed in the footsteps of Fridtjof Nansen’s ship Fram, intentionally freezing fast in the Arctic sea ice to study the Arctic climate throughout the year.

Agder, Norway

Humanity’s biggest ever expedition into the polar regions is over! But analysis of the scientific riches has just begun.

Back in the pre-COVID-19 days, after over seven years of planning, in September 2019, a German icebreaker cast off from Tromsø and headed north. The Polarstern, its crew, and a group of scientists were heading into the Arctic Ocean to be frozen into, and drift with, the ice. This is how we learn about the large-scale changes that human activity has forced on the planet.

The project is “Multidisciplinary drifting Observatory for the Study of Arctic Climate” or MOSAiC for short—representing the mosaic of disciplines comprising the research team. The ever-changing picture meant personnel exchanged throughout the year to total over 700 scientists, technicians, and support staff, who were directly involved. Over 80 institutions across 20 countries were represented, including Norway.

Norway, in fact, provided the inspiration. From 1893-1896, Fridtjof Nansen tried to reach the North Pole by freezing his ship Fram into the Arctic Ocean’s ice so that it would drift over the top of the world. Nansen and Hjalmar Johansen eventually left the ship to head for the pole with skis and dogs over the ice. They passed 86°N to set a northernmost record before an adventure-filled trek by foot and kayak back to land.

Polarstern had it much easier, irrespective of pandemic-induced changes of plans, as the ship was resupplied during the year and had aerial support, making good use of its budget exceeding $150 million. It reached the North Pole on Aug. 19, 2020, and then its home harbor of Bremerhaven, Germany, on Oct. 12, 2020.

Now, the intensive work of analysis, interpretation, and application begins across the expedition’s five scientific areas: atmosphere, sea ice, ocean, biogeochemistry, and ecosystem. Norwegian contributors include the Bjerknes Centre for Climate Research in Bergen and the Norwegian University of Science and Technology (NTNU) in Trondheim. All data are available to anyone connected with MOSAiC until Dec. 31, 2022. The next day, MOSAiC’s data will be open to the world, free to download by anyone.

What will we learn? We know already that the Arctic appears to be warming twice as fast as the world’s average due to human-caused climate change. Uncertainties are nevertheless large, creating further uncertainties about wider impacts on the planet, especially when trying to refine global climate models.

One huge data gap has been a lack of observations during the winter and spring. Ice has been too thick and weather conditions too harsh for quick trips to the very high latitudes during the polar night. By freezing into the ice for the year, MOSAiC circumvented this problem.

The behavior and interactions of ice, air, water, and life during the dark Arctic winter, but especially during the sun’s return and the start of the ice melt, have so far been substantially hidden from science. From the ozone layer and cloud formation to cracks in the ice permitting the Arctic Ocean to contact the frigid air, rarely observed complex processes became available to the Polarstern.

Scientific results are already being published. The rapid thinning of Arctic sea ice and less multi-year ice are both confirmed. This means that the ice, through the same drift that brought the ship across the Arctic, carries much less material, including gases, nutrients, organic matter, and metals. All these feed the biological and non-biological cycles creating the Arctic Ocean’s ecosystem, so fluctuations in them change the ecosystem.

Meanwhile, new features of Arctic ice were discovered with an underwater vehicle operated by MOSAiC scientists who stayed on the surface. Based on sites identified by images taken from the vehicle, researchers obtained ice cores, permitting them to describe the specific type of ice and its formation.

Then, 389 days and 60 polar bears after departure, having experienced temperatures below -40°C / -40°F, MOSAiC’s fieldwork phase ended and Polarstern rejoined the inhabited world. It was a very different world from the one from which it departed, as COVID-19 raged on.

And it is a very different world into which we are headed as we transform the planet. But we will know so much more about it, thanks to MOSAiC’s exceptional effort in Arctic science.

For more on MOSAiC, see:

Some research published from MOSAiC is available at:

This article originally appeared in the Dec. 25, 2020, issue of The Norwegian American.

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Ilan Kelman

Ilan Kelman is Professor of Disasters and Health at University College London, England, and Professor II at the University of Agder, Norway. His overall research interest is linking disasters and health, including the integration of climate change into disaster research and health research. Follow him at and @ILANKELMAN on Twitter and Instagram.