G is for Geology (and Giant!)

An astonishing transformation over the last 20,000 years has seen our planet flip from a frigid wasteland into the temperate world upon which our civilisation has grown and thrived. This most dynamic episode in Earth history saw the crust bouncing and bending in response to the melting of the great ice sheets and the filling of the ocean basins; triggering earthquakes, spawning tsunamis and provoking a lively response from the world’s volcanoes. Now there are signs that human-induced climate change is encouraging the sleeping giant beneath our feet to stir once again. Could it be that we are on track to bequeath to our children and their children not only a far hotter world, but also a more geologically dangerous one?

The ground beneath our feet may seem safe and solid, but earthquakes, volcanic blasts and other hazardous natural phenomena leave us in no doubt that this isn’t the case. Earth is a dynamic planet of shifting tectonic plates that is responsive to change, particularly when there is a dramatic climate transition. We know that at the end of the last Ice Age, as the great glaciers disappeared, the release in pressure allowed the crust beneath to bounce back. At the same time, staggering volumes of melt water poured into the ocean basins, warping and bending the crust around their margins. The resulting tossing and turning provoked a huge resurgence in volcanic activity, seismic shocks, and monstrous landslides—the last both above the waves and below.

The frightening truth is that temperature rises expected this century are in line with those at the end of the Ice Age. All the signs, warns geophysical hazard specialist Bill McGuire, are that unmitigated climate change due to human activities could bring about a comparable response. Using evidence accumulated from studies of the recent history of our planet, and gleaned from current observations and modelling, he argues convincingly that we ignore at our peril the threats presented by climate change and the waking giant beneath our feet.

Waking the Giant: How a changing climate triggers earthquakes, tsunamis and volcanoes