Polarstern Mission

Departure for the Arctic

The icebreaker Polarstern departed from the Norwegian port of Tromsø on Friday the 20th of September for a new scientific mission around the North Pole. Around 600 experts will take turns on the ship, covering 2,500 kilometres in 390 days.

The mission mobilises 60 institutes from 19 countries and has a budget of 140 million euros. The Alfred Wegener Institute and the Helmholtz Centre for Polar and Marine Research (AWI) lead the scientific team, which aims to study the Arctic climate in-depth and, in particular, to collect data during the winter and spring months.

These data will be valuable in gaining a better understanding of the region’s contribution to climate change. Indeed, global warming is extreme in the Arctic. The ice is retreating dramatically. Nevertheless, the processes involved in this disaster are complicated for climatologists to decipher.

The departure date was fixed for when the ice cover was at its thinnest to allow the ship to advance as far as possible into the polar region.

A ship trapped in the ice

The mission was named MOSAiC, which stands for Multidisciplinary drifting Observatory for the Study of Arctic Climate. The ship will remain trapped in the ice and drift for many months with the pack ice, and its route cannot be known in advance. Researchers will build a network of stations on the ice around Polarstern, at a distance of up to 50 kilometres. These automated stations will then collect different types of measurements, and they will drift with the ship for more than 1,000 kilometres from first landfall.

A complex climatic interaction

Ice crystals form in the surface layer of the ocean. Lighter than liquid water, they rise to the surface, where they clump together. It is essential to have a good understanding of this mechanism, and more generally of the caloric transfers between the ocean and the atmosphere, for us to be able to predict climate change. Marine currents transport large quantities of energy from temperate latitudes to the Arctic.

Open water cracks are continually forming in the polar ice. Some of these cracks persist, while others close quickly. This open water absorbs the sun’s rays during the summer while the ocean’s heat and moisture dissipate into the air. Researchers are interested in these energy exchanges and the processes of transport, deformation, and melting of the ice during the annual cycle.

Gas exchanges between the ocean and the atmosphere are another critical area of study. These include carbon dioxide and methane, nitrogen oxides, and the processes of transport, deformation, and melting of ice during the annual cycle. Certain gases produced by algae are also thought to play an important and poorly understood role in the precipitation process. Furthermore, large quantities of methane are released by the thawing of permafrost along the Siberian coast. This gas is carried into the Arctic by ocean currents. It is unknown how much of this gas, which is very harmful to the climate, decomposes in the marine environment and is released into the atmosphere.

Inconspicuous treasures

The Polarstern will also study plankton, inconspicuous organisms about which little is known even though they are one of the first links in the oceanic food chain. These small organisms survive the harshness of the polar winter and then multiply rapidly when the ice melts.

Technical constraints

Four icebreaking ships and two aircraft will be used for refuelling and transporting personnel. An ice landing strip more than one kilometre long will therefore be built near the ship.

The Polarstern is a German ship that entered into service in 1982. It is 118 meters long, weighs 12,000 tonnes unladen and carries a crew of 44 people, plus around 50 researchers. It is estimated that the ship, even when stationary, will consume about 15 tonnes of fuel per day to heat and operate its equipment in a hostile environment where temperatures can drop to -50°C.

This exceptional research vessel can make its way through ice a metre and a half thick. It will be equipped with two onboard helicopters to install and maintain measuring stations, among other functions.


From the 1st of January 2023, all data collected by MOSAiC will be available free of charge. They will be made freely available for researchers, NGOs, governments, businesses, and ordinary citizens.