What Climate Change Has to Do with Earthquakes, Volcanoes and Tsunamis

Climate change will cause more earthquakes. It’s as simple as that.

Deniers, start your engines.

If that isn’t enough to enflame the smoldering embers of discourse within those ready to pounce on any and all climate change notions they deem absurd, here’s another assertion: climate change will also lead to more volcanic activity and tsunamis.

The link between a warming climate and geological events isn’t so far-fetched in the eyes of a number of scientists, and the idea isn’t brand new. It was, however, recently cast into the spotlight with the 6.1 magnitude earthquake that struck the Italian village of Amatrice in August and killed 297 people.

The event prompted several click-hungry “news” websites to dig up existing research on the relationship between climate change and geology and then draw their own parallels between the two.

Among those whose work that seems to have been most often cited in these stories was that of Bill McGuire, a professor of geophysical and climate hazards at the University College London.

McGuire has been interviewed often on this topic, on which he has published numerous research papers and books, including his latest, “Waking The Giant: How A Changing Climate Triggers Earthquakes, Tsunamis And Volcanoes.”

The premise of the book, which I have not read, is best explained in a preview of the content:

“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 science behind all of this goes beyond a simple equation – less ice equals less weight on the Earth’s crust – so if you want to read more on that I’d suggest a 2010 paper in the Royal Society.

In an interview conducted by email with the professor – done that way to deal with an eight-hour time difference and scheduling conflicts – he emphasized that these are not his theories alone and that “climate change is already promoting a response from the solid Earth, with increased earthquake activity in southern Alaska in response to the removal of more than 1 km of ice from underlying faults.”

“We are also now seeing a significant increase in large landslides in mountainous regions – Alps, Rockies, Caucasus, Alaska, New Zealand Alps, etc. – in response to more intense heatwaves, which melt and thaw the ice and permafrost that holds mountain faces together,” he added.

Despite his strong belief that climate change is causing and will cause dangerous geological events, McGuire doesn’t see a tie-in between climate change and the Italian earthquake, as so many news sites implied at the time.

“I don’t see any way in which climate change can have contributed towards this event,” he wrote. “It is a pretty normal event for the region.”

What, I asked him, is the greatest geological threat from climate change?

“A difficult one,” he replied. “It might well be the onset of seismic activity in areas that have so far not experienced it in modern times. Greenland is the place to watch. As the ice sheet melts at an increasingly rapid rate, and the ice load is reduced on the crust underneath, faults that have been dormant and accumulating strain for hundreds of thousands of years may rupture, triggering significant earthquakes.”

Greenland’s population may be scant enough to temper any outright urge to panic, but such large seismic events have the potential to trigger submarine landslides that may, in turn, trigger North Atlantic tsunamis, according to McGuire.

“This happened around 8,000 years ago due to big quakes triggered by the post-glacial melting of the Scandinavian Ice Sheet, sending 20-meters high tsunamis across the region,” he wrote.

Living in Southern California, where the San Andreas Fault is an oft-talked about peril, I wanted to know whether climate change will affect the chances of the long-awaited Big One in the Golden State.

The San Andreas was recently cast into news headlines with a story in the San Francisco Chronicle that covered a report from geologists stating there’s a 72 percent probability that one or more quakes of magnitude 6.7 or greater will occur along one of the Northern California faults that are part of the San Andreas Fault system before 2043.

“There are significant earthquakes statistically ‘due’ in the next few decades for both northern and southern California,” McGuire wrote. “Some interesting research has shown that in the past, the San Andreas Fault ruptures more frequently when sea levels are high, and the added ocean load on one side of the fault, promotes unclamping, which allows the fault to move more easily. This could again be a factor as sea level rise accelerates.”

There are plenty of skeptics to counter these theories for sure. And it seems that the more outlandish a climate change theory sounds – climate change equals more earthquakes is inarguably low-hanging fruit – the more fuel there is for deniers.

Don’t you think so professor?

“It is hard, evidence-based science, but when has that ever stopped the deniers spouting utter garbage!!” he replied.