The Island of Doubt

The idea that deglaciation could affect vulcanism is not new. For anyone who thinks that linking climate change to volcanic eruptions is a prime example of over-the-top alarmism, consider this look at the subject in New Scientist in 2006:

Although these forces on the Earth’s crust are subtly changing all the time, their effects are most obvious at times of major or sudden climate change, such as at the beginning and end of an ice age or during the period of climate change we are expected to experience over the coming centuries. As the balance changes between the stresses acting on the crust and the strains held within it, the result can be an increase in volcanic eruptions and earthquakes.

The Earth has seen this pattern many times before. In the past 650,000 years alone, the polar ice caps have expanded far beyond their current limits on seven occasions, locking up huge volumes of water in frozen oceans and vast continental ice sheets before retreating again to higher latitudes. These huge reorganisations of the Earth’s water resulted in dramatic and repeated swings in sea level, with falls as far as 130 metres below today’s level followed by equally spectacular rises. They also led to shifting loads on volcanoes and geological faults. As ice sheets that had pinned down volcanoes and active faults melted away, the Earth’s crust bounced back in a process known as isostatic rebound. As it did so, faults were reactivated and seismic activity increased sharply.

And so on. Melting ice brought on by a warmer climate means reduced pressure on tectonically sensitive sections of the Earth, which changes the forces that determine seismic and volcanic activity. Simple. Nothing particulary remarkable. None of this is to say that the recent Icelandic eruption is a direct result of global warming. No one is saying that. The recent Scientific American article that hints at a general link pointed out that the Eyjafjallajokull “glacier is too small and light to affect local geology.” It also make liberal use of qualifying terms like “may” and “suggest.” For more on the speculative nature of this discussion, see my colleague Erik Klemetti at Eruptions.

Compare the tenor of the scientific musing on the link between volcanoes and the climate change with the pronouncements of a senior Iranian cleric, one Hojatoleslam Kazem Sedighi:

“Many women who do not dress modestly … lead young men astray, corrupt their chastity and spread adultery in society, which (consequently) increases earthquakes.”

Funny, I thought the Earth was supposed to move after the fact, not before. Guess that’s why I’m blog about science instead of theology.