New sea ice is finally starting to form again in the Arctic, scientists reported Wednesday, but not before reaching another record low last Sunday.
"We are now in uncharted territory," Mark Serreze, director of the National Snow and Ice Data Center, said in a statement announcing the record low of 1.32 million square miles -- nearly half the average extent from 1979 to 2010. The extent has been tracked by satellite since 1979.
"While we’ve long known that as the planet warms up, changes would be seen first and be most pronounced in the Arctic," he added, "few of us were prepared for how rapidly the changes would actually occur."
Many experts expect the Arctic to be free of sea ice in summer at some point between 2015 and 2050.
"Recent climate models suggest that ice-free conditions may happen before 2050," noted center scientist Julienne Stroeve. But she added the caveat that the recent sudden rate of decline "remains faster than many of the models are able to capture."
Serreze told NBC News he's figuring on 2030, calling it "a pretty aggressive estimate."
The sea ice extent numbers come after the center reported last month that the summer sea ice on Aug. 26 had broken the previous record low set in 2007 of 1.61 million square miles. On Aug. 26 the sea ice extent was 1.58 million square miles, it said.
"We're smashing a record that smashed a record," center scientist Walt Meier said.
In the 1980s, he said, summer sea ice would cover an area a bit smaller than the Lower 48 states. Now it is about half that.
A report from the National Snow and Ice Data Center shows the Arctic's melting ice is resulting in the lowest sea ice levels since satellites started tracking the measurements in 1979. NBC's Brian Williams reports.
The difference between this year's low and that of 2007 is 293,000 square miles, about the size of Texas, the center noted in its report.
Meanwhile, conditions favorable to new sea ice are taking longer to appear.
"The strong late season decline is indicative of how thin the ice cover is," Meier said. "Ice has to be quite thin to continue melting away as the sun goes down and fall approaches."
The thickness of the ice is also in decline.
"The core of the ice cap is the perennial ice, which normally survived the summer because it was so thick", Joey Comiso, a NASA scientist who uses satellites to study the ice, said in a statement. "But because it's been thinning year after year, it has now become vulnerable to melt."
NASA also noted that a strong August storm that formed off Alaska's coast and moved to the center of the Arctic Ocean had an impact on ice levels.
"The storm definitely seems to have played a role in this year's unusually large retreat of the ice", said NASA scientist Claire Parkinson. "But that exact same storm, had it occurred decades ago when the ice was thicker and more extensive, likely wouldn't have had as prominent an impact, because the ice wasn't as vulnerable then as it is now."
This year follows several of declining summer sea ice.
"The six lowest September ice extents have all been in the past six years," Serreze said. "I think that's quite remarkable."
The experts also noted that what happens in the Arctic doesn't stay there.
The warmer Arctic is adding increased heat and moisture into the climate system, said center scientist Ted Scambos. "This will gradually affect climate in the areas where we live," he said. "We have a less polar pole -- and so there will be more variations and extremes."
The Associated Press contributed to this report.
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