UCL News


Comment: Never mind the weather, climate change could tear apart the very fabric of the Earth

26 May 2006

The idea that climate change is linked to extreme geological events is not as far-fetched as it might sound.

All over the world evidence is stacking up that changes in global climate can and do affect the frequencies of earthquakes, volcanic eruptions and catastrophic sea-floor landslides.

Not only has this happened several times throughout Earth's history, the evidence suggests that it is starting to happen again. While no serious scientist is suggesting that the Sumatran earthquake was triggered by global warming, there is a growing consensus that if climate change continues unchecked, we can expect not only a warmer future, but a more geologically turbulent one too. …

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. …

Not every volcanic eruption and earthquake in the years to come will have a climate-change link, whatever you might read on the web. Yet as the century progresses we should not be surprised by more geological disasters as a direct and indirect result of dramatic changes to our environment. The only saving grace is that a significant increase in volcanic activity would pump large volumes of sulphate gases into the stratosphere, which would cool the Earth's surface and slow global warming, at least for a time. It's a hell of a price to pay, though, for ignoring a phenomenon that could be far more easily sorted if we lived more considered and sustainable lives. …

Professor Bill McGuire, Director of the UCL Benfield Hazard Research Centre, 'New Scientist'