Image courtesy of guano via flickr
More volcanic activity could become the norm in future centuries as global warming-induced ice melting gathers apace. As reported in both the Times and New Scientist, a new study by the University of Leeds' Carolina Pagli has demonstrated that the increased melting of ice caps has accelerated the melting of magma as well. Vatnajökull, Iceland's largest ice cap, has been melting at a rate of 5 cubic km a year; as a result, the pressure on the underlying land has lessened, leading to more of the deep rock formations melting - by up to 10% over the past century.Pagli and her colleagues calculated that the ice cap has around 10% of its mass since 1890, which has caused the underlying land mass to rise by close to 25 m a year; this has led to the formation of an extra 1.4 cu km of magma under Vatnajökull.
So when will the next big eruption come? According to Pagli, that is not yet quite clear: given the magma's depth of formation, about 15 to 112 km, she believes it could take another century or two before it finally comes to the surface and is ejected by volcanoes. When it finally does, however, she estimates that eruptions will then regularly occur every 30 years or so on average.
It's important to note that the potentially "explosive" effects of ice melting in Iceland may not be replicated elsewhere. No, but, for the rest of the world, rising sea levels may do the trick: Bill McGuire of University College London thinks that global warming-induced sea level rises, another unfortunately consequence of melting ice caps, could yield "a massive increase in volcanic activity globally." It's really a lose-lose proposition.