2010 tied for warmest year; walruses flee ice melt

* Arctic sea ice drops to third-lowest level

* Vanishing Arctic ice forces walruses onto land

By Deborah Zabarenko, Environment Correspondent

WASHINGTON, Sept 15 (Reuters) - So far, 2010 is tied for the warmest year on record, and Arctic sea ice reached its third-lowest level, prompting thousands of walruses to haul themselves out of ice-starved waters, U.S. scientists said on Wednesday.

The first eight months of the year match the record set for the same period in 1998 for the highest combined land and ocean surface temperatures worldwide, at 58.5 degrees F (14.7 C), 1.21 degrees F (0.67 degrees C) above the 20th century average, the U.S. National Climatic Data Center said in a statement.

Temperatures for the northern hemisphere summer -- June through August -- were the second-warmest globally, after 1998, the center said.

Most parts of the globe were hotter than average, with the most prominent warmth in eastern Europe, eastern Canada and parts of eastern Asia. Australia, central Russia and southern South America were cooler than average.

Britain had its coolest August since 1993, according to the U.K. Met Office, while China was 2 degrees F (1.1 degree C) above the 1971-2000 average, the warmest August since 1961, the Beijing Climate Center reported.

In the Arctic, sea ice cover appeared to hit its lowest point for the year on September 10, according to the U.S. National Snow and Ice Data Center.