Any open space will do for a game of football, even an ice floe in the sea around Greenland, as the crew of patrol vessel KV Svalbard and scientists from the Norwegian Institute of Marine Research found last week.

Although there were no rowdy spectators to deal with, polar bears remained a threat, which meant that two armed guards had to keep a lookout during the game.

Polar bears depend on the ice for essential activities such as hunting, travelling and breeding. The earlier melting and later freezing of the ice in recent years has hit these animals hard.

The changes in the ice also have implications for the planet, as scientists say the complete melting of the Greenland sheet ice could raise global sea levels by up to 7m.