Survey to probe Arctic ice melt

This year's Catlin Arctic Survey will focus on the thin layer of water immediately under the floating ice.

Arctic ice is melting faster in summer than many computer models predict.

Survey data could improve forecasts of the region's future, and also show how likely it is that the flow of warm water in the North Atlantic, known as the Gulf Stream, will switch off.

This would bring colder weather to the UK and other parts of western Europe.

"The Arctic is one of best barometers of climate change, where we see big changes taking place today," said Simon Boxall from the National Oceanography Centre (NOC) at the UK's University of Southampton.

"This is not just about polar bears - it's about our lives in the UK and in North America."

In early March, four explorers will set off on foot from the geographic North Pole, trekking across the ice and ending up 10 weeks later in Greenland.

They will make regular stops to drill holes through the floating ice and lower a package of instruments into the water on the end of a piece of rope - instruments that measure the water's temperature, salinity and flow.

This data will allow scientists to calculate the rate at which the water is sinking.

See www.bbc.co.uk for more information.