Whether you think they thinned it a little, or thinned it a lot it is undeniable that the the massive undersea volcanoes deep under the Ice Cap had some effect. The story itself is just coming out here and here, since it was just published in Nature although the data was collected last year.
It’s highly unusual to have pyroclastic volcanoes at the depths found due to the massive hydrostatic pressure that deep. Regardless of the depth, the event would have created some warming trapped in the arctic basin, and the underwater magma explosions and earthquakes would have created massive pressures under the ice cap along with some warming. It’s undeniable that the volcanoes would have some effect on the ice cap, the remaining question is how much?
But the new findings, published in Nature, showed that “large-scale pyroclastic activity is possible along even the deepest portions of the global mid-ocean ridge volcanic system.”
Sohn and his colleagues gathered their data in July last year aboard the ice breaker Oden, using state-of-the-art instruments including a mutlibeam echo sounder, two autonomous underwater vehicles and a sub-ice camera designed for the mission.
Both sonar and visual images showed an ocean valley filled with flat-topped volcanos up to two kilometres (1.2 miles) wide and several hundred metres high.
If you remember we also had a previous poster child for global warming, the Larsen B ice shelf in Antarctica. As reported here that could have been due to undersea vulcanism as well since the only area of the antarctic shelf experiencing warming is the segment along the volcanic ridge.
UPDATE 2010: This article isn’t written to deny Global warming – at this point I was worried that some might be jumping to conclusions rather than looking at all factors – which ultimately weakens the argument if it is the case. The fact that volcanoes are also melting ice quicker than we would like should add impetus to the need to do something about AGW rather than delay it.