Look at a map of the world and find the Shetland Islands. Follow the 60 degrees north latitude circle eastwards. You pass through St. Petersburg, the Ural Mountains, Siberia, the Bering Sea, Alaska, northern Canada, the southern tip of Greenland, then back to the Shetlands. All these places are cold, harsh environments, particularly in winter, except the Shetlands, which is wet and windy but quite mild all year. This is because in the UK we benefit from heat brought northwards by the Atlantic Ocean in a current called the Conveyor Belt. This current is driven by surface water being made to sink by the extreme cold in and around the Arctic. It returns southwards through the Atlantic at great depths. Scientists think it is possible that the Conveyor Belt could slow down or stop, and if it did, the UK would get much colder. We know the planet has been warming for the last century or more, and we think this is due to the Greenhouse Effect. Burning fossil fuels puts a lot of carbon dioxide into the atmosphere, which stops heat from leaving the Earth, like the glass in a greenhouse. In a warming world, ice melts faster, and there is a lot of ice on the Earth: ice caps on Greenland and Antarctica, sea ice in the Arctic and Antarctic Oceans, glaciers in high mountains. And we know that the Arctic is the fastest-warming part of the planet. This causes extra amounts of fresh water to flow into the oceans. Now this fresh water can affect the Conveyor Belt by acting like a lid of water too light to sink, so the Conveyor Belt stops. What is the chance of this happening? We do not know, because there is much we do not understand about how the Arctic Ocean works. You need a powerful icebreaker to get into the Arctic Ocean, and that's only really possible in the summer, because in winter the sea ice thickens and the weather is bad. Scientists all over the world agree that the Arctic Ocean is important because it contains a lot of freshwater, which is why, although it is difficult to make measurements in the Arctic, the UK's Natural Environment Research Council has decided to fund a programme of scientific research in the Arctic. We want to be able to make better predictions of how the Arctic climate will change during the 21st century, so this project will help improve our ability to make these predictions. We will do this by improving the way that computer models of the Earth's climate represent the Arctic. We are going to treat the Arctic Ocean as a box, with a top, a bottom, sides and an interior, and we're going to examine all these parts of the box using measurements from space, from ships, from instruments moored to the sea bed, and from robotic sensors attached to drifting sea ice. We'll use all these measurements together to improve the scientific equations within the computer models, and then we'll run the models into the future to create better predictions not just of the Arctic, but of how changes in the Arctic might influence UK, European and global climate. With better predictions, we can make better plans for the future.