ANCHORAGE, Alaska (AP) — About a third of the world's polar bears could be in imminent danger from greenhouse gas emissions in as soon as a decade, a U.S. government report shows. Greenhouse gases are blamed for the climate warming that's reducing the polar bear's summer sea ice habitat. The scientific models attempted to predict the effects on polar bear populations under two scenarios: one in which greenhouse gas emissions stabilized, and the other in which they continued unabated. Under either scenario, the bears in the Alaska, Russia and Norway group — with an estimated population of about 8,500 — would start to be affected in either 2025 or 2030, said lead author Todd Atwood, an Alaska-based USGS research wildlife biologist. There are other steps we can take to slow the decline of polar bears, but in the long run, the only way to save polar bears in the Arctic is to reduce greenhouse gas emissions.