12/9/2015 2:22:35 PM
The Best Present for Polar Bears
At the top of every polar bear's wish list is sea ice. Unlike most of us, polar bears strive to pack on major pounds during the winter months, but their ability to do so hinges on the extent of sea ice, and therefore access to seals, throughout their range.
Across the Arctic, the sea ice extent for November was the sixth lowest in the satellite record and 910,000 km2 (351,000 mi2) below the 1981 to 2010 average, but there is currently enough sea ice to allow polar bears access to seals in many regions.
Western Hudson Bay polar bears are now out hunting after three to four months on land. As of December 1st, however, sea ice extent was below average in western regions of the bay and above average in eastern regions. As a result, different strategies have emerged from different bears.
On PBI's Bear Tracker, two bears traveled up the coast of Hudson Bay and got out relatively early onto large stretches of ice forming in the north. Another bear decided to save energy by staying closer to home, but currently has less ice on which to hunt. Only time will tell which strategy was more effective.
Time is very important when considering the future of sea ice. A study by Julienne Stroeve and colleagues indicates that, for the next few decades, sea ice may be more impacted by the current greenhouse gas (GHG) content of the atmosphere and natural variability in Arctic climate, rather than any changes we make to GHG emissions now-in other words, it will take time for the greenhouse gases already in the atmosphere to dissipate.
However, reducing GHG now will matter by the middle and later part of the 21st century. Therefore, if we lower emissions today, September ice extent could begin to stabilize around 2050.
Such studies are important for policy makers at the COP21 talks in Paris to consider: lowering emissions now will help protect polar bears (and people) into the future.