By Deborah Zabarenko, Environment Correspondent

WASHINGTON (Reuters) - The state of Alaska has sued the U.S. government, arguing that listing polar bears as a threatened species will hurt Alaskan oil and gas exploration, fisheries and tourism.

The lawsuit, filed on Monday in federal court in Washington, seeks the withdrawal of a May 14 decision to list the big Arctic bears as threatened under the Endangered Species Act because climate change is melting their sea ice habitat.

"We believe that the ... decision to list the polar bear was not based on the best scientific and commercial data available," Alaska Gov. Sarah Palin said in a statement.

Polar bears live only in the Arctic and depend on sea ice as a platform for hunting seals. The U.S. Geological Survey reported last year that two-thirds of the world's polar bears -- some 16,000 -- could be gone by 2050 if predictions about melting sea ice hold true.

In putting the white bears on the threatened list, Interior Secretary Dirk Kempthorne acknowledged that human-caused greenhouse gas emissions contributed to the planetary warming that has damaged the polar bears' habitat.

However, the decision does nothing to address climate change, and Kempthorne said any real solution to that underlying problem is up to the world's economies.

"BIDDING OF OIL COMPANIES"

The Interior Department does not comment on pending litigation and had no statement on the Alaska suit.