Scientists are increasingly keen to find out what's going on because they consider the Arctic the "canary in the mine" for global warming—a warning of what's in store for the rest of the world.
Russia has already planted a flag on the sea bed at the North pole while Canada has increased funding for cold weather training centres and new patrol vessels
Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the Arctic and are displacing birds of less vigorous species.
Most of the Arctic is covered in snow and ice, which are highly reflective; if snow and ice melt, the exposed soil, which absorbs heat, serves to accelerate warming.