Harsh Summer for Sea Ice

September 7, 2011

Polar bears on sea ice Summer is coming to a close in the Northern Hemisphere, and to say it was not a good year for Arctic sea ice would be something of an understatement. In fact, the National Snow and Ice Data Center reports that this August was the second lowest month ever for sea ice since satellite record-keeping began in 1979 (higher only than an all-time low in 2007). But the melt season isn’t over yet–and with one more week to go, sea ice already covers less than two-thirds of the area it covered in the early 1970s. Both the Northwest Passage and the Northern Sea route appear to be open, and several large areas of open water (polynyas) have opened within the ice pack.

What does this mean for the marine mammals who call the sea ice home? This August, as many as 8,000 walruses gathering sought refuge on the northwest coast of Alaska. But an early haul-out on the beach is no safe alternative to their customary sea ice. Not only do the walruses lose access to the shallow waters of the continental shelf where they dive for clams, snails and other food, but large groups of the animals on land also face the danger of stampedes. In September 2009, more than 130 mostly young walruses were crushed after a disturbance spooked a walrus herd at Alaska’s Icy Cape.

Pacific walrus, courtesy FWS Ice-loss trends are having serious impacts on polar bears. As sea ice melts, reports of bears swimming miles from shore, drowning and even resorting to cannibalism have become alarmingly frequent. Without sea ice providing them access to seals, they must search farther inland for food, risking interaction with people and communities.

Scientists are at work to figure out why the ice is disappearing so fast, trying to collect better data through new satellite, plane and submarine observations–even drilling holes and poking a tape measure down to measure ice thickness. They say the thinning of ice over recent decades may hasten an ice-free summer as soon as 2020.

Until then, there are things we can do to help marine mammals like walruses and polar bears adapt to a changing landscape. From protecting these animals under the Endangered Species Act to preserving what shrinking habitat they have, we can help increase the chances of their survival in an uncertain future.