To notice something is going on with the world’s ice sheets, you could measure melting water runoff, glacier retreat or use satellites and GPS to measure ice volume decline.

Just like measuring sea level rise and temperature this all adds to the same picture of a gradually warming world. Now there seems to be yet another route, as research shows there are geological consequences to ice sheet decline as well.

In 2011 we’ve had various Arctic melting records, but for Earth’s climate system as a whole probably the year before that was more dramatic. Not only was 2010 the hottest year on record, it broke many other climate records too, like Caribbean coral bleaching, Amazon drought, and ice melting on the surface of the Greenland ice sheet – which led to an ice loss of 500 gigatonnes.

According to an international research group investigating Greenland melting that last event led to an accelerated bedrock rise – on top of the existing trend, as the ice sheet grows (slightly) lighter year by year and therefore exerts ever less pressure on the Earth’s crust.

Normally GPS measurement stations on southern Greenland show a rise of about 15mm (0.58 inches) on average per year. During the five month melting season of 2010 the tectonic uplift jumped to 20mm (0.79in). Little tectonic movement occurred at stations in the north of Greenland.

The researchers conclude the following from their work: “This result confirms the ability of GPS networks in Greenland, Antarctica and elsewhere to directly sense ice mass changes at sub-annual as well as longer timescales. [Such] networks can therefore mitigate the loss of ice mass measurements following the anticipated termination of the GRACE satellite mission. This result also suggests that ice mass varies over a range of time scales, rather like sea level.”

Lead author Michael Bevis of the School of Earth Sciences of Ohio State University presented the results on Friday at the American Geophysical Union meeting in San Fransisco.

© Rolf Schuttenhelm | www.bitsofscience.org