Saturday, May 14, 2016

Global warming won’t just change the weather—it could trigger massive earthquakes and volcanoes (?)

There's a grain of truth in what he says.  Drastic warming would cause crustal uplift in circumpolar regions -- but all the rest is speculative, entirely dependent on CO2 causing warming.  That there is no correlation between the two seems not to bother him

Bill McGuire is not optimistic about humanity’s future. In his book, Waking the Giant: How a changing climate triggers earthquakes, tsunamis, and volcanoes, he explains why.

By his estimation, carbon dioxide emissions from human activity since industrialization began have changed the trajectory of earth’s climate for the next 100,000 years. We are already experiencing the mayhem and destruction that these changes can wreak, and, in the long term, things are only going to get worse.

On the face of it, the hypothesis that a few degrees’ rise in the average temperature of the atmosphere can cause the earth’s tectonic plates to move sounds ludicrous. Yet, McGuire, professor of geophysical and climate hazards at University College London, shows through careful analysis of historical records that the relationship between the weather and the “solid” earth is incontrovertible.

We caught up with him recently to talk about his hopes and fears. Here’s an edited and condensed version of our conversation.

Q. How is that human activities in the last two centuries could have an effect on the earth’s climate for the next 100,000 years?

McGuire: The climate system takes so long to respond and return to normal. We had a period about 55 million years ago, called the Paleocene-Eocene Thermal Maximum (PETM). It was a period of about 10,000 years, where global temperatures rose by about 6°C [11°F]. This is extremely rapid in geological terms. We had palm trees in Russia; crocodiles swimming in the Arctic ocean.

It sounds incredible, but the really scary thing is that we could now see our temperatures go up by 6°C in a few hundred years.

What we are doing now, and if we carry on doing it for the next few centuries, is raise temperatures in 1/50th of time it took to do the same in the PETM. The rate at which we are raising the global average temperature is simply unprecedented.

Q. But wasn’t there a time when the global temperatures were even higher, like 15°C higher than pre-industrial times?

What we’ve done now is that we’ve taken all the carbon from hundreds of millions of years, which has been locked up in fossil fuels, and we’ve stuck it in the atmosphere in a time of two hundred years.

Then there are the feedback effects that will kick in. Human-caused warming will trigger natural events, which will increase temperatures further. One of those is the release of methane permafrost, especially that stuck under the Arctic.

We don’t need to wait till 2100 to trigger that. People who are working on this say that we could see the release of this permafrost at any time. There’s potential for tens of billions of tonnes of methane to be released just like that [snaps fingers]. Some of these releases could bring global warming prediction ahead by as much as 30 years.

People don’t understand these events. They think it’s a gradual ramping up of the temperature. The real impacts are extreme events—storms, droughts, floods—but also potentially even more extreme events, like these methane outbursts.

Q. OK, so, say that happens. Temperatures go up. When do we then see the effects on the solid earth?

We could see that very soon. The big worry is Greenland. It has 2-3 km (1.2-1.9 miles) of ice on top of its lithosphere. That weight is pushing down the crust. Taking that ice off could trigger earthquakes.

We’re seeing that in Alaska. A lot of ice has been lost in the last 100 years, and the faults there are lot more active now. Previously, because of the weight, they couldn’t move but they were accumulating strain because of the earth’s movement.


Posted by John J. Ray (M.A.; Ph.D.).

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