Dear EarthTalk: Is there any link between increased volcanic activity—such as the recent eruptions in Iceland, Alaska and elsewhere—and global warming? -- Ellen McAndrew, via e-mail
It’s impossible to pin isolated natural phenomena—like an individual volcanic eruption—on global warming, but some researchers insist that there is a correlation between the two in some instances.
“Global warming melts ice and this can influence magmatic systems,” reports Freysteinn Sigmundsson of the Nordic Volcanological Centre at the University of Iceland. Her research with Carolina Pagli of the University of Leeds in England suggests that rocks cannot expand to turn into magma—the primary “feedstock” for volcanic eruptions—when they are under the pressure of a big ice cap pushing down on them. As the theory goes, melting ice caps relieve that pressure and allow the rocks to become magma. This in turn increases the chances of larger and/or more frequent eruptions in affected regions, from Iceland to Alaska to Patagonia to Antarctica.