Satellite measurements of the Kangerdlugssuaq glacier show that, as well as moving
more rapidly, the glacier's boundary is shrinking dramatically - probably because
of melting brought about by climate change.
The Kangerdlugssuaq glacier on Greenland's east coast is one of several that
drains the huge Greenland ice sheet. The glacier's movements are considered
critical in understanding the rate at which the ice sheet is melting.
Kangerdlugssuaq is about 1,000 metres (3,280ft) thick, about 4.5 miles wide,
extends for more than 20 miles into the ice sheet and drains about 4 per cent
of the ice from the Greenland ice sheet.
Experts believe any change in the rate at which the glacier transports ice
from the ice sheet into the ocean has important implications for increases in
sea levels around the world.
If the entire Greenland ice sheet were to melt into the ocean it would raise
sea levels by up to seven metres (23ft), inundating vast areas of low-lying
land, including London and much of eastern England.
Computer models suggest that this would take at least 1,000 years but even
a sea-level rise of a metre would have a catastrophic impact on coastal plains
where more than two-thirds of the world's population live.
Measurements taken in 1988 and in 1996 show the glacier was moving at a rate
of between 3.1 and 3.7 miles per year. The latest measurements taken this summer
show it is now moving at 8.7 miles a year.
Gordon Hamilton, professor of earth sciences at Maine University, who made
the measurements using global positioning system (GPS) satellites, said the
velocity measurements were accurate to within about 45 metres of movement per
year and that Kangerdlugssuaq is probably the fastest-moving glacier in the
"This is a dramatic discovery. There is concern that the acceleration
of this and similar glaciers and the associated discharge of ice is not described
in current ice-sheet models of the effects of climate change," Professor
"These new results suggest the loss of ice from the Greenland ice sheet,
unless balanced by an equivalent increase in snowfall, could be larger and faster
than previously estimated."
Kangerdlugssuaq is a relatively southern glacier and the scientists are concerned
that more northerly glaciers, which have not shown such an increase in speed
of movement, may follow suit if the warming of the Arctic region continues.
Professor Hamilton said: "As the warming trend migrates north, glaciers
at higher latitudes in Greenland might also respond in the same way as Kangerdlugssuaq
"In turn, that could have serious implications for the rate of sea-level
The independently funded scientists from Maine made the measurements from the
Greenpeace ship Arctic Sunrise which is sailing off the Greenland coast documenting
the signs and impacts of climate change in the Arctic.
Martina Krüger, Greenpeace's expedition leader, said there were signs
that the glacier was both retreating and moving faster at the same time.
"The speed up of the glacier is due to increased surface melting, which
generates meltwater that trickles down to the glacier bed and lubricates the
bedrock," Ms Krüger said.
"This decreases the friction and the glacier slides more easily. This
is accompanied by a thinning of the glacier, because the glacier stretches more.
"The front or terminus of the glacier is usually pinned or anchored to
a higher feature on the ocean floor, such as a ridge from where it calves icebergs.
"As the glacier thins, it will float off that pinning point. Once the
glacier has lost that anchoring, it retreats into deeper water behind that pinning