(Corrects name of agency to U.S. National Snow and Ice Data
Center, instead of U.S. National Climate Data Center, in first
paragraph)
* Unprecedented lows would beat 2007 mark
* Early melting set the stage, August saw quick thaw
By Deborah Zabarenko
WASHINGTON, Aug 20 (Reuters) – Sea ice in the Arctic Ocean
is likely to shrink to a record small size sometime next week,
and then keep on melting, a scientist at the U.S. National Snow
and Ice Data Center said on Monday.
“A new daily record … would be likely by the end of
August,” said Ted Scambos, lead scientist at the data center,
which monitors ice in the Arctic and elsewhere. “Chances are it
will cross the previous record while we’re still in sea ice
retreat.”
The amount of sea ice in the Arctic is important because
this region is a potent global weather-maker, sometimes
characterized as the world’s air conditioner. This year, the
loss of sea ice in the Arctic has suggested a possible opening
of the Northwest Passage north of Canada and Alaska and the
Northern Sea Route by Europe and Siberia.
As parts of the Arctic melted, 2012 also set records for
heat and drought in much of the Northern Hemisphere temperate
zone, especially the continental United States.
This summer could see the ice retreat to less than 1.5
million square miles (4 million square km), an unprecedented
low, Scambos said.
The previous record was set in 2007, when Arctic ice cover
shrank to 1.66 million square miles (4.28 million square km), 23
percent below the earlier record set in 2005 and 39 percent
below the long-term average from 1979 to 2000.
However, 2007 was a jaw-dropping “perfect storm” of
conditions that primed the area for thawing sea ice: warmer and
sunnier than usual, with extremely warm ocean water and winds
all working together to melt the Arctic.
Last year, Arctic sea ice extended over the second-smallest
area on record, but that was considered to be closer to a “new
normal” rather than the extreme conditions of 2007, NSIDC said
then.
This year is similar to 2011, Scambos said by telephone from
Colorado. The melt season started between 10 days to two weeks
earlier than usual in some critical areas including northern
Europe and Siberia.
SIGNS OF CLIMATE CHANGE
If the sea ice record is broken this month, that would be
unusually early in the season; last year’s low point came on
Sept. 9, 2011.
Typically, the melting of Arctic sea ice slows down in
August as the Northern Hemisphere moves toward fall, but this
year, it has speeded up, Scambos said. “I doubt there’s been
another year that had as rapid an early August retreat,” he
said.
Overall, the decline of Arctic sea ice has happened faster
than projected by the United Nations Intergovernmental Panel on
Climate Change five years ago, according to NSIDC data ( http://nsidc.org/news/images/20070430Figure1.png
).
To Scambos, these are clear signs of climate change spurred
by human activities, notably the emission of heat-trapping
greenhouse gases including carbon dioxide.
“Everything about this points in the same direction: we’ve
made the Earth warmer,” he said.
This summer has also seen unusual melting of the ice sheet
covering Greenland, with NASA images showing that for a few days
in July, 97 percent of the northern island’s surface was
thawing. The same month also saw an iceberg twice the size of
Manhattan break free from Greenland’s Petermann Glacier.
The change is apparent from an NSIDC graphic showing current
Arctic ice cover compared with the 1979-2000 average, Scambos
said. The graphic is online at http://nsidc.org/arcticseaicenews/
.
“What you’re seeing is more open ocean than you’re seeing
ice,” he said. “It just simply doesn’t look like what a polar
scientist expects the arctic to look like. It’s wide open and
the (ice) cap is very small. It’s a visceral thing. You look at
it and that just doesn’t look like the Arctic Ocean any more.”
(Editing by Doina Chiacu)
