"A Greater Survival Threat Than Asteroids" --NASA Proposes a Solution for Earth's 20 Supervolcanoes That Erupt Once Every 100,000 Years

There are around 20 known supervolcanoes on Earth, with major eruptions occurring on average once every 100,000 years, according to the BBC resulting in mass starvation, with a prolonged volcanic winter potentially prohibiting civilization from having enough food for the current population. In 2012, adds the BBC, the United Nations estimated that food reserves worldwide would last 74 days.

NASA Jet Propulsion Laboratory scientist Brian Cox said that "I came to the conclusion that the supervolcano threat is substantially greater than the asteroid or comet threat." He proposes that the logical solution could simply be to cool a supervolcano down by extracting its heat. NASA estimates that if a 35% increase in heat transfer from the Yellowstone supervolcano --essentially a gigantic heat generator, equivalent to six industrial power plants--could be achieved from its magma chamber, it would no longer pose a threat.

Six hundred thousand years ago there was a colossal explosion from a cauldron of magma, the most massive known supervolcano, the 2.2 million acre Yellowstone caldera that forms the world's highest plateau capping a seething magma chamber forty-five miles across-the size of Rhode Island- and eight miles thick of hot molten rock that rises up from 125 miles from the Earth's core. When Yellowstone explodes, and it will again, someday, Hiroshima will look like child's play. What no knows for sure is, when.

The ancient Yellowstone caldera exploded with such violence that it left an ash layer almost ten feet deep a thousand miles away in eastern Nebraska killing all plant life and covering almost all of the United States west of the Mississippi. 

Modern geological surveys have shown that this supervolcano erupts approximately every 600,000 years. The Blackfoot Indians called it the land of evil spirits -what we know today as Yellowstone National Park.

A volcano the size of Yellowstone, says Wilcox, currently leaks about 60-70% of the heat coming up from below into the atmosphere, via water which seeps through cracks into the magma chamber. The remainder builds up inside the magma, enabling it to dissolve more and more volatile gases and surrounding rocks. Once this heat reaches a certain threshold, then an explosive eruption is inevitable.

Building a massive water aqueduct uphill into a mountainous region like tyhe Yellowstone Plateau "would be both costly and difficult," says Wilcox. "and people don’t want their water spent that way. People are desperate for water all over the world and so a major infrastructure project, where the only way the water is used is to cool down a supervolcano, would be very controversial.”

NASA has come up with different plan to drill up to 10km down into the supervolcano, and pump down water at high pressure. The circulating water would return at a temperature of around 350C (662F), thus slowly day by day extracting heat from the volcano. 

And while such a project would come at an estimated cost of around $3.46 billion, it comes with an enticing catch which could convince politicians to make the investment.

“Yellowstone currently leaks around 6 giga watts in heat,” Wilcox says. “Through drilling in this way, it could be used to create a geothermal plant, which generates electric power at extremely competitive prices of around $0.10/kWh. You would have to give the geothermal companies incentives to drill somewhat deeper and use hotter water than they usually would, but you would pay back your initial investment, and get electricity which can power the surrounding area for a period of potentially tens of thousands of years. And the long-term benefit is that you prevent a future supervolcano eruption which would devastate humanity.”

“The most important thing with this is to do no harm,” Wilcox says. “If you drill into the top of the magma chamber and try and cool it from there, this would be very risky. This could make the cap over the magma chamber more brittle and prone to fracture. And you might trigger the release of harmful volatile gases in the magma at the top of the chamber which would otherwise not be released.”

Instead, the idea is to drill in from the supervolcano from the lower sides, starting outside the boundaries of Yellowstone National Park, and extracting the heat from the underside of the magma chamber. “This way you’re preventing the heat coming up from below from ever reaching the top of the chamber which is where the real threat arises,” Wilcox says.

“With a project like this, you’d start the process and the main ongoing benefit you’d see in everyday terms is this new supply of electrical power,” Wilcox says.

“When people first considered the idea of defending the Earth from an asteroid impact, they reacted in a similar way to the supervolcano threat,” Wilcox says. “People thought, ‘As puny as we are, how can humans possibly prevent an asteroid from hitting the Earth.’ Well, it turns out if you engineer something which pushes very slightly for a very long time, you can make the asteroid miss the Earth. So the problem turns out to be easier than people think. In both cases it requires the scientific community to invest brain power and you have to start early. But Yellowstone explodes roughly every 600,000 years, and it is about 600,000 years since it last exploded, which should cause us to sit up and take notice.”

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