Geophys. Res. Lett. 35, L09304 (2008)


The melting of Iceland's largest ice cap, Vatnajökull, over the last century has relieved pressure on the Earth's crust below, leading to the production of magma beneath the surface, shows a new study. The research lends weight to the idea that more frequent volcanic eruptions could be among the consequences of climate change.

Carolina Pagli, then at the University of Luxembourg, and Freysteinn Sigmundsson of the University of Iceland estimated the rate of pressure decrease in the mantle beneath Vatnajökull, which lost ten per cent of its mass during the twentieth century, and then modelled the associated changes in the rock and magma. The recent ice melt increased production of magma by 1.4 cubic kilometres per century, their model showed — adding about ten per cent to the estimated 17 cubic kilometres of magma per century that forms under Iceland from plate-tectonic processes independent of climate.

The authors speculate that the effects of ice loss may also have deflected the magma from its usual path, explaining why a large eruption in 1996 occurred at a site between two existing volcanoes. The calculated volume of extra magma, if it all erupted, could recreate the 1996 eruption every 30 years.