(UPDATE: Since this was posted, more than 21,000 Earthjustice supporters sent comments to the Minerals Management Service opposing expansion of oil and gas exploration in the "Polar Bear Seas.")

The Beaufort and Chukchi seas are home to one in five of the world’s remaining polar bears. That’s why these icy waters north and west of Alaska are often called the Polar Bear Seas.

They’re also crucial feeding and migration zones for bowhead, beluga and other whales, as well as seals, walruses and migratory birds.

This is America’s Arctic, already under assault from global warming—and now, threatened by a massive expansion of the oil and gas drilling that fuel climate change.

In its final days, the Bush administration moved to open up almost 75 million acres of the Beaufort and Chukchi Seas to drilling. In the last eight years, 4 million acres of the Arctic Ocean had already been leased for drilling—an eightfold increase over what had been leased previously.

Last year, the polar bear became the first creature listed under the Endangered Species Act specifically because of the effects of global warming. The Arctic is warming at twice the rate of the rest of the planet, causing sea ice to melt at an accelerated pace—and leaving polar bears and other creatures with shrinking options for survival.

The Minerals Management Service estimates the proposed leases could bring up to 400 new wells and 600 miles of new offshore and onshore pipelines. In the Chukchi alone, MMS says the increase in drilling carries up to a 50 percent chance of a major oil spill—even though 20 years after the Exxon Valdez catastrophe no technology exists to clean up a spill in the Arctic’s icy conditions. Today as much as 16,000 gallons of oil still foul Prince William Sound, and biologists recently reported that a fragile population of killer whales that hunts in the Sound have never recovered from the spill and are doomed to die off.

More leasing and drilling in America’s Arctic would be disastrous for the polar bear, for global warming and for our hopes to build a clean energy future. What we need is a ‘time out’ for the Arctic, to assess the damage we’ve already done and determine how to protect what’s left.

The Obama administration’s response to the Bush proposal will be an important early test of its resolve to fight global warming and its promise to restore scientific integrity in environmental and energy policy. The Minerals Management Service is also taking public comments on the proposal through March 30.