WASHINGTON (AP) — Critical ice in the Arctic Ocean melted to record low
levels this sweltering summer and that can make weather more extreme far
away from the poles, scientists say.
The National Snow and Ice Data Center reported Monday that the extent of
Arctic sea ice shrank to 1.58 million square miles and is likely to melt
more in the coming weeks. That breaks the old record of 1.61 million square
miles set in 2007.
The North Pole region is an ocean that mostly is crusted at the top with
ice. In the winter, the frozen saltwater surface usually extends about 6
million square miles, shrinking in summer and growing back in the fall.
That’s different from Antarctica, which is land covered by ice and snow and
then surrounded by sea ice.
Normally sea ice in the Arctic reaches its minimum in mid-September and then
starts refreezing. But levels on Sunday shrank 27,000 square miles — about
the size of West Virginia — beyond the old record.
Figures are based on satellite records dating back to 1979. The ice center
bases its figures on averages calculated over five days.
Data center scientist Ted Scambos said the melt can be blamed mostly on
global warming from man-made emissions of greenhouse gases.
There are natural factors involved too, including a storm that chewed up a
significant amount ice earlier this month. But, he said, dramatic summer sea
ice losses in all but one year since 2007, continuous thin ice, and warm air
temperatures show a pattern that can only be explained by climate change.
“It really does imply that the Arctic is moving to a new state,” said NASA
ice systems program scientist Tom Wagner. “The Arctic is changing.”
Wagner and Scambos said in 2007 some people thought it was just an odd year
that caused the dramatic melt, but years like this one show something bigger
This milestone is a “substantial step” to the day when there will be no
significant sea ice in the Arctic in the summer, said NASA chief scientist
"Why do we care?,” Abdalati, an ice scientist, asked. “This ice has been an
important factor in determining the climate and weather conditions under
which modern civilization has evolved.”
Scientists sometimes call the Arctic the world’s refrigerator and this is
like leaving the fridge door open, Scambos said.
“This is kind of a knob on global weather,” Wagner said. “We don’t know the
impact yet” of fiddling with it.
Scientists say Arctic sea ice helps moderate temperatures further south in
the winter and summer. A study earlier this year in the peer-reviewed
journal Geophysical Research Letters linked some of the factors behind
Arctic sea ice loss to higher probabilities of extreme weather “such as
drought, flooding, cold spells and heat waves.”
Scientists also say sea ice is crucial for polar bears and other animals.
Wagner said the changes in Arctic sea ice fits with glacier loss in Alaska
and Canada and ice loss in Greenland. Earlier this summer, NASA satellites
reported a dramatic melt in Greenland, where nearly every part of its
massive ice sheet started melting, something that last happened in 1889.
Ohio State University ice scientist Jason Box has been monitoring Greenland,
where he said temperatures have sometimes been 9 to 18 degrees warmer than
normal this summer and the ice is reflecting far less heat — and thus
absorbing more energy — than ever before.
Global warming physics for years has been saying if greenhouse gases are
causing climate change, the Arctic will feel it first with loss of sea ice
and melt in snow and ice on land, Box said.
“We’re in a declining trend because the Earth is getting warmer,” Scambos
said. “It’s going to continue to be a series of shrinking ice extents year
by year... We’re not going back.”
National Snow and Ice Data Center: