Southern Ocean rise due to warming, not ice melts

By Michael Byrnes

SYDNEY (Reuters) - Rises in the sea level around Antarctica in the past decade are almost entirely due a warming ocean, not ice melting, an Australian scientist leading a major international research program said.

The 15-year study of temperature and salinity changes in the Southern Ocean found average temperatures warmed by about three-tenths of a degree Celsius.

Satellites also measured a rise of about 2 centimeters (about an inch) in seas in the southern polar region over an area half the size of Australia, Rintoul told Reuters.

"The biggest contribution so far has been from warming of the oceans through expansion," said Steve Rintoul, Australian leader of an Australian-French-U.S. scientific program.

Melting sea ice or Antarctic ice shelves jutting into the ocean do not directly add to sea level rises.

Rintoul was speaking as French ship L'Astrolabe prepared to depart on Monday from Hobart, on Australia's southern island of Tasmania, for its fifth voyage of the current summer season for the Surveillance of the Ocean Astral (Survostral) program.

The research program has been taking temperature and salinity readings for 15 years to a depth of 700 meters along the 2,700 km, six-day route between Hobart and the Antarctic.

This has produced the longest continuous record of temperature and salinity changes in the Southern Ocean for scientists studying how the ocean contributes to global climate.