Washington, Oct 7 (IANS) The extent of the Arctic Sea ice this year or the area covered by floating ice was the third lowest since satellite measurements were first made in 1979.

The ice area at minimum was an increase from the past two years, but still well below the average for the past 30 years.

Arctic Sea ice reached its minimum extent around Sep 12. According to scientists affiliated with the National Snow and Ice Data Centre (NSIDC), sea ice coverage dropped to 5.10 million square km at its minimum.

The ice cover was 970,000 square km greater than the record low of 2007 and 580,000 square km greater than 2008.

NSIDC is sponsored by several US agencies, including NASA. Ice data are derived from measurements made by the US Department of Defence and NASA satellites, with key work in interpreting the data and developing the 30-year history done by scientists at NASA's Goddard Space Flight Centre.

"The changes from year to year are interesting since there has been large variability," said Josefino Comiso, a sea ice expert at NASA Goddard. "But we need to look at several years of data to examine the long-term trends."

"Our three decades of continuous satellite measurements show a rapid decline of about 11.6 percent per decade," Comiso said. Arctic Sea ice has declined about 34 percent since measurements were first made in the late 1970s.

"The oceans are crucial to earth's climate system, since they store huge amounts of heat," said Comiso. "Changes in sea ice cover can lead to circulation changes not just in the Arctic Ocean, but also in the Atlantic and Pacific Oceans. If you change ocean circulation, you change the world's climate."

IANS