a year of startling data pointing to a warming world, the thin
blue line in the chart below of Greenland's ice melt was
initially dismissed as just too outlandish to be accurate.
is home to the world's second largest ice mass, containing enough
water to lift average sea levels about seven metres if it all melted.
early-season melting of Greenland ice has scientists worried.Photo:
Daniel Beltra, via Catherine Edelman Gallery (Chicago)
in early April, signs that the giant ice sheets were melting at least
a month earlier than typical during the three decades-plus
of reliable records stunned scientists at the Danish
had to check that our models were still working properly" Peter
Langen, a climate scientist at DMI, told Polar
lies on part of the glacial ice sheet that covers about 80 per cent
air sweeping in from the south-west of Greenland had prompted
more than 12 per cent of the ice sheet to register melting.
stations 1840 metres above sea-level reported temperatures
of above 3 degrees, conditions that would be considered a warm day in
July, let alone April.
flows along a glacial river on the Greenland ice sheet last
New York Times
is melting", said Aqqaluk Petersen, a resident of
Nuuk, Greenland's capital.
heatwave, Greenland style, added to other evidence that the top of
the world continues to warm about twice as fast as the rest of the
is really the big show when it comes to ice melt," said
Matt King, Professor of Polar Geodesy and an ARC Future
Fellow at the University of Tasmania. "It's probably
losing as much ice as all the small glaciers around
the world combined, and probably more than Antarctica.
is being eaten away from away from above and from the edges."
air temperatures have risen about two degrees since the
1960s. Ocean temperatures are also warming, thawing
Greenland glaciers in contact with surrounding seas.
records date only from the 1970s, some natural fluctuations may be in
play, he said. Still, Greenland's early April warmth
was consistent with other signals of a warming planet.
a big spike in melting so early is in complete agreement
with what you'd expect when we heat the atmosphere so
much," Professor King said, referring to the impact from
humans burning fossil fuels and releasing other greenhouse gases.
Arctic sea ice, for instance, also set a record low maximum
range this year, setting up a shorter-than-usual melt season in
spring and summer, according to the US
National Snow and Ice Data Center.
Less ice also fosters more warming since there is less reflection of
solar radiation back into space, with more of the warmth absorbed by
the now ice-free waters.
conditions mean there are more days when polar temperatures are
positive, meaning that they is more melting of surface ice.
April's early warm spurt in Greenland eased back, the loss of
ice mass has continued, running at about two months ahead of the
average for the period since 1990, according to the DMI.
loss of a gigatonne of ice per day amounts to about one cubic
kilometre, or one billion tonnes, of water.
the 2003-2011 period, Greenland net annual ice loss was 234
cubic km of water. That's enough to lift global sea levels by an
average of 0.65 mm, the DMI said.
process of mass loss started around 1990 and has accelerated since
the year 2000," the Polar Portal said. "The mass loss in
recent years is approximately four times greater than it was before
King said that one effect of early melting is that the surface snow
turns to water, exposing the darker glacial ice below. That ice has a
lower albedo effect, trapping in more warmth and adding to the
warm start to April, meanwhile, has continued for much of the month,
leaving Greenland on course for a month well-above normal