A 'science city' on the Arctic sea-ice

It is without question the biggest science expedition ever undertaken to the Arctic. Germany's Research Vessel (RV) Polarstern is going to lock itself in the Arctic sea-ice and drift across the top of the planet. It'll take a year. Hundreds of experts will visit the ship in that time, using it as a base to study climate change. The Mosaic expedition leader is Prof Markus Rex from the Alfred Wegener Institute. He spoke about the project's aims and challenges with our science correspondent Jonathan Amos.

Picture courtesy of Stefan Hendricks