The Arctic is currently undergoing a 'phase of dramatic change', according to the latest results from scientists investigating sea-ice and ocean conditions on the roof of the world. The international team of researchers is on board the Polarstern, a research vessel of the Alfred Wegener Institute for Polar and Marine Research (AWI). Their work will contribute to the International Polar Year (IPY), as well as to a number of EU-funded projects. 'The ice cover in the North Polar Sea is dwindling, the ocean and atmosphere are becoming steadily warmer, the ocean currents are changing,' commented Dr Ursula Schauer, Chief Scientist at the AWI and a member of the expedition to the Arctic. 'We are in the midst of a phase of dramatic change in the Arctic, and the International Polar Year 2007/08 offers us a unique opportunity to study this dwindling ocean in collaboration with international researchers.' Of particular concern to the researchers is the thinning of the sea-ice; across large areas of the Arctic, the sea-ice is now just one metre thick, equating to a 50% thinning since 2001. Current models suggest that the Arctic could be ice-free in as few as 50 years. On board the Polarstern are researchers who are studying the plants and animals which live in and beneath the sea ice; when the ice disappears, many of these organisms will face extinction. Other scientists on the ship are looking at ocean currents and temperature changes. At over 100 places, researchers have taken temperature, salinity and current measurements. Measurements taken on previous trips reveal that the current coming into the Arctic from the Atlantic is getting warmer. The researchers are also studying the impacts of the large amounts of freshwater coming into the Arctic from the large rivers of Siberia and North America. This freshwater appears to act as an insulating layer, controlling the transfer of heat between the ocean, the ice and the atmosphere. The Polarstern is due to return to its home harbour of Bremerhaven, Germany in October, but that does not mean the research activities in the Arctic will come to an end. A series of buoys has been released across the Arctic Ocean, and over the coming months they will continuously collect data on currents, temperature and salinity and send the data via satellite to the scientists. Meanwhile the expedition's blog provides more evidence of the warming Arctic climate, as this entry, recorded when the ship was at its northernmost point, 88° 40' N, shows. 'Of course, we had expected that even here the ice would be as eroded and loose as in all other regions that we visited during the past weeks which has allowed us to maintain a speed of up to 6 [knots],' writes Dr Schauer. 'But a whole day of rain within 150 km of the North Pole came somewhat as a surprise! For the past few weeks, one low pressure system after another has continuously carried warm air from northern Siberia (15° C at the Lena estuary!) towards the central Arctic Ocean. In this way the sea ice disintegrates more and more right before our eyes.'