ANCHORAGE, Alaska Sea-ice coverage across the Arctic Ocean has dwindled to its second-lowest level since satellite records started in 1979, the National Snow and Ice Data Center reported on Tuesday.
Areas of the Arctic with at least 15 percent sea-ice as of Saturday totaled 1.68 million square miles, slightly above the record-low of 1.61 million square miles recorded in 2007, the center said.
Yet to be determined is whether Tuesday's reported sea-ice cover will be the lowest for the year. Annual minimums are usually reached around mid-September.
"We're getting close, but there's still the potential for further loss of ice," said Walt Meier, a research scientist at the Boulder, Colorado-based National Snow and Ice Data Center.
Ice coverage could diminish either through more melt or from winds or both, Meier said. However, some areas, including those near the North Pole, were showing signs of ice growth, he said.
"Probably there's a little bit of both going on - there's melting and refreezing," he said.
At least one other institution has reported that this year's Arctic ice coverage was the lowest on record. A report issued last week by the University of Bremen in Germany said sea-ice coverage on September 8 fell below the 2007 minimum.
The University of Bremen researchers use finer-resolution measurements that can better distinguish smaller areas of ice and open water, Meier said. But that university's methodology also has some drawbacks, he said.
ICE COVER DIMINISHED OVER RECENT DECADES
Under either measurement, however, Arctic ice cover has diminished dramatically over recent decades. Saturday's coverage, as measured by the National Snow and Ice Data Center, was only about two-thirds the average coverage measured from 1979 to 2000.
Reduced sea ice is believed to have cascading impacts on climate in the circumpolar north and even lower latitudes.
According to an academic study released on Tuesday by the U.S. Geological Survey, Yupik Eskimo residents in southwestern Alaska are living with some of those affects.
The study, published in the current edition of the journal Human Organization, examined observations of elders and longtime hunters in two Lower Yukon River villages.
The residents detailed dramatic changes over the years in river-ice thickness, a public-safety risk because no roads connect villages in that part of Alaska, and residents in winter travel over river ice.
The residents also testified to changing ranges for several animals, particularly moose and beavers, changes in vegetation and concerns about reduced availability of driftwood that used to be pushed downstream by powerful currents of spring meltwater.
With river ice reduced, spring thaws are less powerful or dramatic than they were in the past, according to the Yupik residents interviewed for the study.
"Many climate change studies are conducted on a large scale, and there is a great deal of uncertainty regarding how climate change will impact specific regions," Nicole Herman-Mercer, a USGS social scientist and one of the study's authors, said in a statement.
"This study helps address that uncertainty and really understand climate change as a socioeconomic issue by talking directly to those with traditional and personal environmental knowledge."
(Editing by Dan Whitcomb and Cynthia Johnston)