The Polarstern icebreaker supports research in the Arctic Alfred-Wegener-Institut / Mario Hoppmann

The biggest scientific project ever to take place in the Arctic is about to kick off. Within days, a ship is set to begin drifting in the sea ice off Siberia, from where it will eventually become locked in the ice for months of the Arctic winter.

The Polarstern icebreaker is set to depart from Norway on 20 September – around the same time that researchers are expected to confirm the area of Arctic sea ice has reached the second lowest level on record. The ship is part of an epic endeavour called MOSAIC, which will involve some 600 scientists studying climate change, Arctic wildlife and more over the course of a year.

Winter sea ice in the Arctic is too thick even for icebreakers to penetrate. Instead, the expedition will borrow an idea pioneered by Norwegian explorer Fridtjof Nansen who in the 19th century took advantage of a major ocean current to drift to the central Arctic. “It doesn’t make sense to fight the ice, rather we are going to work with it,” says the expedition’s leader, Markus Rex of the Alfred-Wegener Institute for Polar and Marine Research in Germany.


The expedition will be an complex logistical endeavour. The Polarstern, loaded with scientific equipment, fuel and food, will be supported by a fleet of four other icebreakers. For half a year the ice will be impenetrable, so a runway on the ice will operate to fly in supplies.

The scientific research will involve a camp on the ice that might stray as far as 50 kilometres from the ship. Scientists will study the atmosphere, the physics of sea ice, and ocean chemistry among much else.

The behaviour of the region’s rapidly-declining sea ice, which is expected to disappear entirely over summer in coming decades due to climate change, has been well-studied in summer. But for winter, Rex says there is little data beyond satellite images and basic temperature records from ocean buoys.

New field observations should help build better models of climate change in future. Rex says some models predict the Arctic will warm by 5°C compared to pre-industrial temperatures by 2100 but others predict 15°C of warming. The range is huge and needs narrowing, he says.

Donald Perovich at Dartmouth University, who will be aboard the Polarstern, says the mission should also tell us more about Arctic snow – where it is, how it builds up in winter and melts in summer, and how it is blown around. The team should also find out more about how the bottom of sea ice melts.

“It’s the biggest sea ice experiment ever, by a large margin,” says Perovich. “The number of countries, the number of scientists, the number of icebreakers: it’s a once in a lifetime opportunity.”