Geological disasters might influence climate, for instance when volcanic debris blots out the sun. But climate cannot disrupt geology. Right? Well, actually no, says a British geologist Bill McGuire, in a troubling new book, Waking The Giant: How a Changing Climate Triggers Earthquakes, Tsunamis and Volcanoes.
There is, McGuire argues, growing evidence to incriminate changing climate in the planet’s most destructive geological events. Melting ice sheets and changes in sea level can, he maintains, set off the largest earthquakes and volcanic eruptions. Indeed, thanks to climate change, a human hand may already be at work. Potentially, McGuire’s argument adds a whole new dimension to why we should be worried about climate change.
The most solid evidence for climatic influence on geology comes from the end of the last ice age, around 12,000 years ago, says McGuire, who is a volcanologist and professor of geophysical and climate hazards at University College London. Analysis of volcanic deposits, published in the past decade by several authors, has found that this period of rapid climate change, when ice sheets retreated from much of the planet, coincided with a sudden outburst of geological activity. The incidence of volcanic eruptions in Iceland increased around 50-fold for about 1,500 years, before settling back to previous levels.