Beluga Shipping / AP
In this 2009 photo, a pair of German merchant ships traverse the fabled Northeast Passage through the Arctic.
By John Roach, Contributing Writer, NBC News
Most of the sea ice that forms each fall and winter in the Arctic now melts each spring and summer, a recent change that is impacting global patterns of weather and trade as well as the U.S. military's strategic planning, experts told reporters during a briefing Tuesday.
"There are tremendous two-way and multiple interactions between the Arctic and the rest of the world," retired Rear Adm. David Titley said during the teleconference organized by Climate Nexus, a group trying to raise awareness about climate change.
Experts tied the melting ice in the Arctic to the recent spate of stormy winter weather in parts of the U.S. and Europe. They also noted that the prospect of ice-free summers in the Arctic as soon as 2030 is already impacting international trade and U.S. Navy plans to protect Arctic resources.
Maximum extent reached
The briefing was held the day after the National Snow and Ice Data Center (NSIDC) announced that the Arctic sea ice reached its maximum reach for the year on March 15, covering 5.84 million square miles. This is the sixth lowest maximum sea ice coverage in the 35-year satellite record.
"The last 10 years have been the lowest 10 years," said Walt Meier, a research scientist at the NSIDC. He added that while this year was low, "we actually have the largest growth of ice in our record from the minimum to the maximum" primarily because the ice was recovering from the record low in 2012.?
In addition to the shrinking extent of sea ice, the remaining ice is thinning perhaps twice as fast as the observed ice extent, noted Wieslaw Maslowski, an oceanographer at the U.S. Naval Postgraduate School.
Changing weather patterns
The changing sea ice dynamics are perhaps most felt outside of the Arctic via changes in weather patterns, noted Stephen Vavrus, a senior scientist with the National Institute Center for Climatic Research at the University of Wisconsin-Madison.
Jim Vaiknoras / AP
A storm system stretching from the Dakotas to the Florida Panhandle is predicted to bring snow to the mid-Atlantic states.
The melting ice, he explained, allows heat stored in the ocean to escape to the atmosphere where it changes the pressure patterns, including "the jetstream level winds that affect our weather in the middle latitudes."
In particular, he and colleagues hypothesize that the warming Arctic causes the jetsteam to slow down and meander like a river flowing through the plains. This, in turn, transports less warm air over the lands from the oceans.
"That essentially helps to refrigerate the land during the wintertime and we get more cold and more snow and more extreme cold as well," Vavrus said. "And we've seen examples of that in this past winter with the slowed westerly wind."
The same meandering jetstream, he noted, could also explain the unusually warm spring in 2012. If a meandering jetstream is like a river, some bends are favorable to cold outbreaks, others are favorable to extreme warmth.
"Just depending on how those jetstream waves happen to set up in a particular week or month or season, that could help to explain why you could get weather extremes of both types," he said.
More commerce, new conflicts?
Less ice in the Arctic and the potential for ice-free summers is ratcheting up commercial interest in the region for oil and mineral extraction as well as use as a shipping route, developments that have the U.S. Navy studying how to establish an increased presence there.
"We see the potential for direct armed conflict in the Arctic to be very, very low," Titley said, but the military nevertheless is preparing its ships to be Arctic worthy, to establish infrastructure such as ports, and to strengthen communications and weather forecasting.
"The Arctic it is a very austere and harsh place," he said. "Even as it warms, it's a really hard place to operate."?
John Roach is a contributing writer for NBC News. To learn more about him, visit his website.?
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