by Guest Blogger
July 21, 2005
You ever commute to work, and find your office building missing when you
get there? That’s probably what it felt like this Monday morning for
University of Maine glaciologist Dr. Gordon Hamilton.
He was commuting
to his place of work (a glacier of course) with Hughie, flying the
helicopter, and Melanie, one of our campaigners in the back seat.
Gordon, along with his PhD student Leigh Stearns, had already plotted
exactly where they wanted to place their precision GPS receivers, a
kilometer from the front of the glacier. But arriving at the research
coordinates, Gordon discovered something was missing. “Yeah, it was
quite a surprise when we came up here this morning,” he explained later,
“and found that as we flew over the way points marked for the survey
grid, we were still over water and the calving front of the glacier was
quite a bit further up the fjord.”
Here’s a satellite image of the Kangerdlugssuaq glacier. The older
colored lines represent where the glacier ended based on aerial and
satellite surveys. The dotted orange line is an estimate of where the
glacier ends today, based what we’ve seen. As you can see the change is
pretty dramatic. (Image courtesy of ASTER Science Team / University of Maine)
The Kangerdlugssuaq glacier has been surveyed using aerial and satellite
images since 1962. In all that time (and very likely for quite some
time before) its front has remained remarkably stable.
Now, over just a
few years, it’s retreated roughly three miles (5km). Previous research,
done by NASA, had shown the glacier thinning at a rapid rate – about 33
feet (10m) per year. It had been a little puzzling to Gordon how the
glacier could thin so fast without retreating. As he says, “Of course,
when we flew over Monday morning, once we saw the quite large retreat,
it started to make sense.”
A fast flowing ice river
Plotting a new research grid, Gordon and Leigh went about the work of
measuring how fast the ice that makes up this glacier is flowing
Work that was complicated by 20 knot winds, and a more
chaotic glacial surface than any they’d ever been on before.
Towering pinnacles ready to collapse, tiny landing zones, and crevasses
hidden under the weathered surface by ice debris all hampered their
efforts. Nonetheless, the science team spent far longer out on this
glacier than any other on this trip – taking additional measurements to
try and figure out what’s going on here.
Their extra work paid off, though, and brought them another surprise.
When this glacier was last measured, in 1995, it was flowing at a fairly
speedy (for a glacier) 3.72 miles (6km) per year. Yet, preliminary
results from Gordon and Leigh’s survey suggest that since then it’s
speed has more than doubled, to almost nine miles (14km) per year –
making it one of the word’s fastest. As Gordon put it, “that’s pretty
All this ice has to come from somewhere. In this case, as with many
other Greenland glaciers, it’s flowing from the Greenland ice sheet.
Not that the ice sheet itself will disappear completely anytime soon.
That would take hundreds and hundreds of years.
But if the
Kangerdlugssuaq glacier is an example of what’s to come, then it could
go much faster than current models predict. In fact, we could be
looking at several feet of sea level rise over the next hundred years –
enough to wreck massive damage. More than 70 percent of the world’s
population lives on coastal plains, and 11 of the world’s 15 largest
cities are on the coast or estuaries. Weather patterns would also
change as the ice sheet shrinks. And the millions of gallons of melted
ice water would alter regional seawater salinity and global ocean
currents. In short, if the Greenland ice sheet is in fact draining
rapidly it will be a disaster of global proportions.
We’ll keep doing our part by bringing you news from the frontlines of
climate change, but we need you to join us in action. Everyone needs to
pitch in, but if you’re in the U.S. (the world’s biggest global warming
polluter per capita) your help is especially needed.