Fracking Greenland

That’s not fracking as in hydraulic fracturing to extract natural gas, but simply fracturing, as in really big pieces of Greenland breaking off and floating away.

I’m guessing everyone who reads this site has heard the news and knows that NASA snapped a couple of before and after photos of a 2.7 square mile chunk of ice breaking off Greenland from the Jakobshavn Isbrae glacier. Of course we should refrain from reading too much into this, as ice calves from glaciers and ice sheets all the time in the Arctic and Antarctic regions, even if this was a particularly big example of the phenomenon.

What I found interesting about the event was the ice dynamics, as described by Larry O’Hanlon in Discovery News (emphasis added):

Jakonbshavn is already well known for being a major exit route for 10 percent of the ice that leaves Greenland for the sea. The river of ice fills a vast valley which, if emptied, would rival the Grand Canyon in scale.

It appears that the record retreat of Jakonbshavn may have been helped by an exceptionally warm winter, which prevented sea ice from forming in front of the glacier, said Ian Joughin of the Polar Science Center Applied Physics Lab at the University of Washington.

There’s usually about four miles of sea ice floating in front of the glacier, keeping the water nice and chilly near the calving front of the glacier — and less prone to calving off icebergs.

Normally the glacier retreats in the summer, then regains ground in winter as it surges towards the sea with the help of sea ice. The lack of sea ice appears to have changed that, say researchers.

“This year it started (calving) where it left off last summer,” said Ian Howat of the Byrd Polar Research Center at Ohio State University.

I don’t think you have to read too far between the lines to see a fundamental change how Greenland’s ice responds to Spring and Summer weather, a change that looks a lot like yet another tipping point. The sea area around the glaciers has less ice and more open water, which provide less (or even no) back pressure to slow down the flow and calving of glaciers. As others have pointed out about similar situations (possibly in Antarctica?), it’s like pulling the cork out of a bottle.

This is also another good example of why I think a lot of what climate scientists do in general is much tougher than it looks. Not only are we recording events that humans have never seen before, but in a large and complex system, and one that we don’t understand as well as we wish, these events can trigger other changes in the Earth System. This isn’t just a theoretical issue, but one that probably explains part of what we see in two of the scariest graphs about Greenland one could imagine:

(These are both from the excellent piece by John Cook on Skeptical Science, Watts Up With That concludes Greenland is not melting without looking at any actual ice mass data, which you simply must go read.)

The caption for the second graph above says, “The black line is a straight-line (constant acceleration) fit through the mass balance data for the period 1996-2008 with a slope of 21 gigatonnes/yr2“. So not only is Greenland losing 286 billion tons of ice per year, but the rate of loss is itself increasing by 21 billion tons/year. I’ll leave it as an exercise for the reader to figure out which of those numbers is more unsettling. I vote for the 21, but that could be my economics background talking, as we’re trained to focus on change, as in marginal cost and marginal revenue.

And while I’m on the topic of icy vistas, let me add that the book I’m currently reading, Henry Pollack’s A World Without Ice, is excellent, at least through the 92 pages I’ve read so far. I will likely post a full review when I’m done.

In case you’re wondering what’s going on way up north, here’s the current view from one web cam very close to the North Pole:

See the home page for the North Pole Environmental Observatory here.