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Other evidence of a major climatic change after the Permian die-off include sudden shifts in ratios of elements such as carbon and oxygen found worldwide. Researchers have long thought that volcanic gases from the Siberian Traps could have altered Earth's climate. Because the Siberian Traps' magma punched through sedimentary rocks such as coals and carbonates, the eruptions could have cooked the rocks, pouring extra billions of tons of greenhouse gases and toxic metals into Earth's atmosphere, according to modeling studies presented yesterday. Particles similar to fly ash from coal-fired power plants appear in lake sediments on Canada's Ellesmere Island, downwind of Siberia in the Permian, said Stephen Grasby, a geochemist at Canada's Geological Survey.
Gases such as carbon dioxide and methane warmed the Earth, and sulfur dioxide pelted the Northern Hemisphere with acid rain, researchers said. (Siberia was in the high latitudes 252 million years ago, so gases and ashes circled in the north.) "Rain in the Northern Hemisphere could have been really intensely acidic," said Benjamin Black, a postdoctoral researcher at MIT. "The pH was comparable to undiluted lemon juice."
Black created a computer model of Earth's atmosphere during the Siberian Trap eruptions, when most of Earth's landmasses were jammed together in a supercontinent called Pangaea. A giant ocean called Panthalassa covered the rest of the globe.
Just one year's worth of volcanism from the Siberian Traps, or about 57 cubic miles (240 cubic km) of lava, could generate 1.46 billion tons of sulfur dioxide and devastate the Northern Hemisphere, Black's study found. [Big Blasts: History's 10 Most Destructive Volcanoes]
The toxic gases pouring from the Earth also created chemical reactions that destroyed the protective ozone layer, raising DNA-damaging ultraviolet radiation over much of the planet, Black said. "Globally, average ozone levels fall below those observed in the Antarctic ozone hole in the 1990s," he said.
In total, more than 1,200 billion tons of methane and 4,000 billion tons of sulfur dioxide could have emerged from the Siberian Traps eruption, said Henrik Svensen, a geologist at the University of Oslo in Norway.
So there were a whole lot of other toxic gasses being expelled that contributed to the event.
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