ANCHORAGE, Alaska (MCT) – According to scientists, 20,000 to 25,000 polar bears plod around Alaska today.

In 50 years there may be none.

Government scientists predicted Friday that the entire population may be extinct from this area, with loss of habitat as the number one reason.

Shrinking sea ice will leave only a remnant surviving population of the world’s polar bears in the islands of the Canadian Arctic by mid-century, according to a breathtaking new study by the U.S. Geological Survey. Two-thirds of the world’s polar bears, including those along the coasts of Alaska and Russia, will have disappeared.

The loss of sea-ice habitat is so high that regional efforts to protect them, such as restricting subsistence hunting or arctic oil and gas development, will not be able to prevent their disappearance, the government scientists said.

Unfortunately, it is irreversible, too, the study said.

Even a dramatic effort to reduce greenhouse gas emissions would not be enough to halt the near-term warming trend and save the coastal bears. The species might manage to survive in its remnant outposts if long-term warming trends are reversed, scientists said.

“Things could be turned around so that they don’t disappear completely,” said Steve Amstrup, the biological study team leader for the USGS. On the other hand, Amstrup said, climate-warming models chosen for the study tended to be conservative, so the bears might disappear faster than predicted.

“As the sea ice goes, so goes the polar bear,” Amstrup said, adding that 84 percent of the population have been affected by this change.

The new set of USGS studies, provided to Congress Friday, were undertaken to aid Interior Secretary Dirk Kempthorne’s decision whether to designate polar bears a “threatened” species under the Endangered Species Act. A decision is due by next January.

The state of Alaska has strenuously opposed a federal threatened-species listing, arguing, among other things, that bear populations have been stable and that too much uncertainty surrounds projections of global warming trends.

The picture of doom is even more dire than the one painted by environmentalists when they sued the federal government over polar bears in 2005, prompting the endangered-species review by Kempthorne.

“This is not a reason to despair or give up,” said Deborah Williams, president of Alaska Conservation Solutions, an Anchorage-based organization focused on global warming. “Our generation has the ability to write a death sentence for the polar bear, or to take action to assure that the species survives.”

POLAR BEARS • Polar bears are the largest land predator alive today. • Adult male polar bears weight between 770 to 1,500 pounds. • Polar bears range in color from silvery-white to light yellow to straw yellow. • When a polar bear dives underwater, its ear canals close. – www.bear.org