Greenland Ice Sheet Faces 'Tipping Point in 10 Years'

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The Guardian/UK

Greenland Ice Sheet Faces 'Tipping Point in 10 Years'

Scientists warn that temperature rise of between 2C and 7C would cause ice to melt, resulting in 23ft rise in sea level

by
Suzanne Goldenberg

An enormous chunk of ice, roughly 97 square miles in size, has broken off the Petermann Glacier along the northwest coast of Greenland. (Photograph: Aqua/Modis/Nasa)

WASHINGTON - The entire ice mass of Greenland
will disappear from the world map if temperatures rise by as little as
2C, with severe consequences for the rest of the world, a panel of
scientists told Congress Tuesday.

Greenland shed its largest chunk
of ice in nearly half a century last week, and faces an even grimmer
future, according to Richard Alley, a geosciences professor at
Pennsylvania State University

"Sometime in the next decade we may
pass that tipping point which would put us warmer than temperatures that
Greenland can survive," Alley told a briefing in Congress, adding that a
rise in the range of 2C to 7C would mean the obliteration of
Greenland's ice sheet.

The fall-out would be felt thousands of
miles away from the Arctic, unleashing a global sea level rise of 23ft
(7 metres), Alley warned. Low-lying cities such as New Orleans would
vanish.

"What is going on in the Arctic now is the biggest and fastest thing that nature has ever done," he said.

Speaking
by phone, Alley was addressing a briefing held by the House of
Representatives committee on energy independence and global warming.

Greenland
is losing ice mass at an increasing rate, dumping more icebergs into
the ocean because of warming temperatures, he said.

The stark warning was underlined by the momentous break-up of one of Greenland's largest glaciers last week, which set a 100 sq mile chunk of ice drifting into the North Strait between Greenland and Canada.

The briefing also noted that the last six months had set new temperature records.

Robert
Bindschadler, a research scientist at the University of Maryland, told
the briefing: "While we don't believe it is possible to lose an ice
sheet within a decade, we do believe it is possible to reach a tipping
point in a few decades in which we would lose the ice sheet in a
century."

The ice loss from the Petermann Glacier was the largest
such event in nearly 50 years, although there have been regular and
smaller "calvings".

Petermann spawned two smaller breakaways: one of 34 sq miles in 2001 and another of 10 sq miles in 2008.

Andreas
Muenchow, professor of ocean science at the University of Delaware, who
has been studying the Petermann glacier for several years, said he had
been expecting such a break, although he did not anticipate its size.

He also argued that much remains unknown about the interaction between Arctic sea ice, sea level, and temperature rise.

Muenchow
told the briefing that over the last seven years he had only received
funding to measure ocean temperatures near the Petermann Glacier for a
total of three days.

He was also reduced, because of a lack of
funding, to paying his own airfare and that of his students to they
could join up with a Canadian icebreaker on a joint research project in
the Arctic.

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