Yellow submarine to probe Antarctica glacier

By Alister Doyle, Environment Correspondent

PUNTA ARENAS, Chile (Reuters) - A yellow robot submarine will dive under an ice shelf in Antarctica to seek clues to world ocean level rises in one of the most inaccessible places on earth.

The 7-meter (22 ft) submarine, to be launched from a U.S. research vessel, will probe the underside of the ice at the end of the Pine Island glacier, which is moving faster than any other in Antarctica and already brings more water to the oceans than Europe's Rhine River.

Scientists have long observed vast icebergs breaking off Antarctica's ice shelves -- extensions of glaciers floating on the sea -- but have been unable to get beneath them to see how deep currents may be driving the melt from below.

They are now stepping up monitoring of Antarctica, aware that any slight quickening of a thaw could swamp low-lying Pacific islands or incur huge costs in building defenses for coastal cities from Beijing to New York.

The rate of flow of the Pine Island glacier in west Antarctica has quickened to 3.7 km (2.3 miles) a year from 2.4 km in the mid-1990s.

"It's taken everyone by surprise," Adrian Jenkins, leader of the "Autosub" mission at the British Antarctic Survey, told Reuters just before leaving this week after preparations in Chile. The submarine cost several million dollars to develop.

"If you just make measurements at the ice front all you have is a black box," Jenkins said. "What we are doing is observing what is going on within the box."

Antarctica holds more than 90 percent of the world's fresh water and would raise ocean levels by 57 meters (190 ft) if it were all to melt, which would take thousands of years.