Saturday, September 8, 2007

Glacial Earthquakes? Uh-oh

Risk assessment for the impacts of climate change must be an active, ongoing, constantly-updated process. We're learning all the time, especially about feedback systems that affect the speed of change.

Here's an example of where the risk assessment for sea level rise is suddenly requiring a significant adjustment. The quickening pace of ice breaking off from the Greenland icecap means that our current estimates of sea level rise are both too low and too slow.

Thanks to Dave Roberts at Gristmill for pointing to this article in the Guardian (UK):

Melting ice cap triggering earthquakes

· Estimates of sea-level rise out of date, say scientists
· Religious leaders pray for planet at Greenland glacier

And from The Independent (UK) via Climate Ark, this ominous quote:
The accelerating thaw and the earthquakes are intimately connected, according to [Finnish scientist Veli Albert Kallio], as immense slabs of ice are sheared from the bed rock by melt water. Those blocks of ice, often more than 800m deep and 1500m long, contain immense rocks as well and move against geological faults with seismic consequences. The study of these ice quakes is still in its infancy, according to [American polar expert Robert Correll], but their occurence is in itself disturbing. "It is becoming a lot more volatile," said Mr Vallio. Predictions made by the Arctic Council, a working group of regional scientists, have been hopelessly overrun by the extent of the thaw. "Five years ago we made models predicting how much ice would melt and when," said Mr Kallio. "Five years later we are already at the levels predicted for 2040, in a year's time we'll be at 2050."

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