ANCHORAGE, ALASKA ? The polar bear is mentioned only obliquely in the latest international survey of global warming science – as a “predator high in the food chain” likely to suffer as sea ice melts in the Arctic.

But Alaska’s 1,200-pound “canary in the coal mine” is looming larger than ever in the debate over the effects of man-made greenhouse gases and what – if anything – should be done about them.

The state House of Representatives passed a resolution last week opposing efforts to list the polar bear as “threatened” under the federal Endangered Species Act. Arguing that the bears are doing fine worldwide, Alaska House Speaker John Harris, R-Valdez, dismissed as an “unfounded, unproven scientific hypothesis” the notion that release of carbon dioxide into the atmosphere is causing climate change.

Resources committee co-chairman Rep. Craig Johnson, R-Anchorage, issued a statement warning that the polar bear is being used by environmental groups to serve a “bigger, darker agenda” to punish business and change American habits.

The House measure, which passed 30-9, called on other states to join Alaska in opposing the designation of polar bears as threatened. House members said that air-pollution rules intended to slow the melting of polar ice could affect distant projects such as new power plants in the Lower 48.

The state Senate passed a similar measure last week. The 12-5 vote was largely along party lines, though some rural Democrats in both houses voted with the majority. Concerns have been raised that an endangered-species listing could affect subsistence.

Meanwhile, the Palin administration is drawing up comments to oppose the federal listing.

The U.S. Fish and Wildlife Service deadline for public comments on listing the polar bear is Monday. A decision on the listing is expected in January 2008.

Polar bears are considered marine mammals. They spend their summers and falls on sea ice while hunting seals, their chief prey.

The latest report of the United Nations Intergovernmental Panel on Climate Change, released Friday in Belgium, assesses the likely effects of warming trends. Part one of the report, issued two months ago, focused on climate-change models. The earlier report predicted sea ice would continue shrinking as global temperatures climbed. That report said it was 90 percent certain that humans were the main cause of warming since 1950.

The latest report summarizes the work of several hundred scientists from around the world and was approved this week by officials from more than 100 countries. A 1,500-page detailed report of this phase, dealing with effects and the likelihood of adaptation, is expected out in May.

Because warming trends have been stronger in northern latitudes, Alaska has documented more effects of a changing climate than most places. But that hasn’t translated into strong political pressure from Alaska for action to reduce carbon emissions.

Though polar bear numbers are fairly stable worldwide, the northern Alaska population is thought to be in decline, according to the federal listing proposal. Advocates of increased protection point to scientific studies showing incidents of polar bear drownings, cannibalism and starvation, and higher cub mortality.

State officials have said protecting the bears under the Endangered Species Act could mean new limits on North Slope oil and gas production, for instance by declaring the Arctic coastline to be critical habitat for the bears. They have raised questions about the varying climate models used to project rates of melting ice, which reach differing conclusions.

Some officials say listing the polar bear would create a broad new reach for the Endangered Species Act, given the global source of the emissions that most scientists say are causing the bear’s problem.