Not liking the sound of Russian submarines

In the icy waters of the Arctic, Nato scientists are dissecting sound waves to improve the West's ability to track Russian submarines, as global warming alters acoustics underwater.

"The only reliable source of information is acoustic waves," Gaultier Real, the head scientist on board the Nato research vessel, Alliance, said during a stop in the northern Norwegian town of Tromso, on the eve of an expedition to the Barents Sea.

The oceanographic ship, operated by the Italian navy, is transporting Real's team of scientists to the polar front, where the waters of the Atlantic and Arctic meet.

The aim of the mission is to understand how climate change, which is warming the Arctic faster than the rest of the planet, is affecting the movement of underwater soundwaves.