Greenland and climate


in Daily updates

Tristan Laing playing his guitar

A recent Nature article highlights the vulnerability of Greenland, in the face of climate change, as well as the realities of asymmetric situations in the climate:

But there’s a disturbing sense in which Greenland shouldn’t be here in the first place. It is a holdover of the most recent ice age, a creature of conditions that no longer apply. No ice sheet would grow in Greenland if the current one were to vanish — even without human-induced warming, the climate would not allow it. The ice is a relic, stranded out of time. And relics are fragile.

The view that the Earth is uniquely and permanently well suited to human life is a dangerous fallacy. Indeed, the most recent geological epoch (The Holocene) has been a period of unusual stability. We have no reason to count on the Earth remaining so accommodating, even in the absence of climatic forcings caused by human activities.

The complexity of this whole issue makes it a subject of confusion for many, and an opportunity for some to be maliciously disingenuous. It is absolutely right to say that the climate has natural cycles. It is also vital to recognize that human greenhouse gas emissions are producing major climatic changes, that those changes endanger us, and that action must be taken to stabilize emissions. That will not guarantee us a stable climate over the course of tens or hundreds of thousands of years, but it would keep us from inducing massive climatic changes through our own doings, over the span of decades or centuries.

The article also highlights the importance of The Gravity Recovery and Climate Experiment (GRACE): a two-satellite instrument that tracks gravitational changes. The two satellites fly 220 kilometres apart and closely track their exact distance from one another. Along with data from accelerometers and celestial navigation, this lets them track gravitational anomalies. Data from GRACE corroborates other forms of measurement to suggest that Greenland is losing something in the vicinity of 154 to 211 billion tonnes of ice per year. Last year’s exceptional summer may have involved a loss of 500 billion tonnes.

The article itself has lots more interesting detail that I will not replicate here. Instead, I encourage those who are interested to have a look for themselves.

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. April 18, 2008 at 4:28 pm

Moulins, Calving Fronts and Greenland Outlet Glacier Acceleration

Guest Commentary by Mauri Pelto

The net loss in volume and hence sea level contribution of the Greenland Ice Sheet (GIS) has doubled in recent years from 90 to 220 cubic kilometers/year has been noted recently (Rignot and Kanagaratnam, 2007). The main cause of this increase is the acceleration of several large outlet glaciers. There has also been an alarming increase in the number of photographs of meltwater draining into a moulin somewhere on the GIS, often near Swiss Camp (35 km inland from the calving front). The story goes—warmer temperatures, more surface melting, more meltwater draining through moulins to glacier base, lubricating glacier bed, reducing friction, increasing velocity, and finally raising sea level. Examining this issue two years RealClimate suggested this was likely the correct story. A number of recent results suggest that we need to take another look at this story.

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