Global warming triggers quakes

Scientists today reveal another reason to tackle global warming – it triggers earthquakes.
They say there is clear evidence that climate change affects the frequency of quakes, volcanic eruptions and catastrophic landslides on the ocean floor.
Turbulent geological changes have already happened several times through the Earth’s history – and they warn that they appear to be starting to happen again.
The climate interacts with the Earth’s crust through the weight of water and ice being shifted around the planet’s surface, New Scientist reports today.
Pressure caused by this weight can trigger seismic and volcanic activity and even landslides.
Professor Bill McGuire, of University College London, says: “Dumping the weight of a kilometre-thick ice sheet onto a continent or removing a deep column of water from the ocean floor will inevitably affect the stresses and strains on the underlying rock.”
When temperatures rose after the last ice age, around 10,000 years ago, it caused a burst of volcanic activity in Iceland.
Scientists are particularly concerned about catastrophic melting of the ice sheet around Greenland which could trigger quakes and underwater landslides.
This could generate tsunamis more than 60ft high hitting the Shetlands and north coast of Scotland.
The Greenland ice sheet and that in the West Antarctic have already been recognised to be melting more rapidly than before and could cause sea levels to rise by several yards over thenext few centuries.
McGuire says his own research team studied sediment from beneath the Mediterranean and found that the intensity of volcanic activity has been directly linked to the rate of sea-level change over the past 80,000 years.
McGuire, professor of geological hazards, says that 57 per cent of the world’s 600 or so active volcanoes are on islands or the coast and 38 per cent lie within 250km (155 miles) of the coast.
Many or all of those volcanoes could be susceptible to the stress changes caused by a rise in sea levels.
McGuire says another worry is that quakes and landslides could release large amounts of methane gas from the seabed.
These “burps” could cause global temperatures to rise even further.
The satellite image above, dated 2000, is from Nasa and demonstrates the thinning ice sheets around Greenland.

Paul Sutherland

Paul Sutherland

I have been a professional journalist for nearly 40 years. I write regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy. I have also authored three books on astronomy and contributed to others.
Paul Sutherland

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Paul Sutherland

I have been a professional journalist for nearly 40 years. I write regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy. I have also authored three books on astronomy and contributed to others.

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