A report in New Scientist describes new research from the University of Alberta, Canada, showing more polar bears are starving. Scientists tranquilized bears and took blood samples in 1985 and 1986, then again in 2005 an 2006. Based on the ratio of two chemicals in the blood, they could tell which bears were fasting (at a time of year when most bears are feasting to store up fat for summer). That number increased three-fold over those 20 years.

Their explanation? Loss of sea ice, on which the bears hunt for seals, and possibly a loss of seals, which build dens for their young on the ice.

The bears’ problems are far from over. Arctic sea ice has been melting for decades, but scientists say that melting has been accelerating over the past few years. Some even say we’ve reached the point of no return, meaning that we’re losing so much ice every year that it won’t be able to recover. There was slightly more ice (4.6 million sq. km) left at the end of fall 2008. But that’s just slightly more than all of 2007 (4.3 million sq. km), the second lowest coverage on record.