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Whether it's glowing lava snaking into the sea or lightning blooming in billowing ash clouds, the sight of an erupting volcano inspires awe and wonder. Now imagine 1,500 of these suckers all shooting off at once. That's how many active volcanoes dot the Earth, plus an unknown number hidden under the ocean. Every day, between 10 and 20 volcanoes are erupting somewhere on Earth, but scientists say the chance of every volcano on the planet erupting at once is so small that it's impossible. But what if it did happen? Would Earth as it we know it survive?
Not likely, said Parv Sethi, a geologist at Radford University in Virginia. Even if only the volcanoes on land blasted in sync, the effects would trigger an environmental domino chain many, many times more powerful than a nuclear winter, Sethi said. "Things will become so bad that I wouldn't want to survive on an Earth like this," he told Live Science.
Sethi predicts that a thick layer of ash would blanket the Earth, completely blocking incoming sunlight. "The planet would be pitched into complete dark, and that is going to devastate photosynthesis, destroy crop yields and cause temperatures to plunge," Sethi said. The ash would linger in the atmosphere for up to 10 years, he added.
Acid rain would wipe out any crops that survived burial by ash, Sethi said. Volcanic gases include nasties such as hydrochloric acid, hydrogen fluoride, hydrogen sulfide and sulfur dioxide, which can become acid rain when they condense high in the atmosphere. That acid rain would contaminate groundwater and the ocean's surface. Ocean acidification would kill off corals and marine creatures with hard shells. The extinctions would travel up the ocean food chain, wiping out fish and other marine life.
Volcanic eruptions do release the greenhouse gas carbon dioxide, which could help offset global cooling from ash and stratospheric particles. But Sethi wondered whether 1,500 simultaneous volcanic eruptions would overwhelm Earth's systems. "It's going to be like turning the knob on a gas stove to the broil setting," he said. "The only question is whether it is actually going to change the [atmosphere's] composition so much that we have carbon dioxide poisoning in the atmosphere. Either way, we're going to be cooked, so to speak," Sethi said.
So what life could survive this deadly volcanic outburst? "It will be the time of the extremophiles," Sethi predicts. The sci-fi strategy is also possible: A few humans live on in orbit or in deep underground bunkers built by well-financed governments or rich moguls, waiting for the atmosphere to clear. "The lucky ones would be the dead ones in this scenario," Sethi said.
