Survey to probe Arctic ice melt

Richard Black in the BBC: Scientists and explorers will shortly set off on an expedition aiming to discover how Arctic sea ice melts. 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.

…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. "We're measuring the critical 200m layer of water between the ice and the deep ocean beneath," said Dr Boxall, who conceived the project. "The hypothesis has been that the layer stays there, trapped, acting to insulate the cold ice from the warm salty water below.

"On the other hand, the water might be taken away more quickly - and that might accelerate the rate of Arctic melting." Even in the era of Earth observation satellites and automonous ocean floats, the old-fashioned approach - sending people across the ice to take readings by hand - is really the only one available for this kind of work, he noted. The findings could prove to be crucial in terms of projecting the future for Arctic sea ice….

Map from Book 12 of the 4^th edition of Meyers Konversationslexikon (1885–90)