A team of independent scientists on board the Arctic
Sunrise is investigating whether warming subtropical ocean
currents are causing Greenland glaciers to melt faster than
While the melt from warming temperatures is a known phenomenon,
the influence of currents is less understood, and new research
conducted by Dr. Fiamma Straneo of the Woods Hole Oceanographic
institution is groundbreaking. (Or, perhaps, "icebreaking"?)
"Over the last decade we've seen dramatic changes in the
Greenland ice sheet; in particular there's been a large loss of
mass of ice from Greenland's outlet glaciers. One of the mechanisms
we think may have triggered these changes is the inflow of warm
subtropical water inside of Greenland's glacial fjords," Dr.
A (frozen) river runs through it
These currents could be causing the dramatic melt of Greenlandic
glaciers. Dr. Gordon Hamilton, of the University of Maine, has been
studying the speed of flow of the Greenland glaciers, and in
particular Helheim glacier.
Glaciers are like frozen rivers, with ice slowly moving
downstream at an average of 50 meters per year. Helheim glacier is
moving at the speed of 25 meters per DAY. Located further North,
the Kangerdlugssuaq glacier moves at an average of 38 meters per
day. This is opening the way for the Greenland ice sheet to
flow out, melt in the Atlantic Ocean, and contribute to sea level
"Kangerdlugssuaq Glacier is probably the world's fastest moving
glacier. It tripled its speed between 2004 and 2005, which tells us
the glacier is moving mass out of the middle of Greenland's ice
sheet, in the form of icebergs, at a rate three times faster than
just a few years ago. This has important implications for both the
mass balance of the Greenland ice sheet, and for the rate of global
sea level rise," said Dr. Hamilton.
Accelerating feedback effects
Other feedback effects in the Arctic are highlighted in a new
WWF report, pointing out that their influence on the global
climate also may have been underestimated.
Arctic multi-year sea ice is increasingly replaced by younger
sea ice, making the ice-cap more vulnerable to melting in the
summer. This allows the surface water to absorb more heat. The
permafrost (permanently frozen ground) is heating up as well,
releasing underground methane, a potent greenhouse gas. This
methane then further contributes to global warming.
This report also points out that the International Panel on
Climate Change's (IPCC) 2007 estimates on sea-level rise were too
optimistic, and offers new estimates of up to 1.2 meters by the end
of the century.
Beyond the tipping point
In 2007, the IPCC reported an
estimated sea-level rise of 20 to 50 cm. As worrying as these
figures were, evidence now suggest things are worse than they'd
thought. The effect that the melting Greenland ice-sheet could have
on sea-level rise was not fully included in the IPCC reports, since
these findings are too recent.
Once we go beyond the tipping point where global warming feeds
itself, there will be no going back. The time for action is now. In
95 days, the Copenhagen climate Conference will start. World
leaders have to show their commitment to the climate by attending
and adopting strong emissions targets.
We can wait no longer.
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