Hugh Pickens DOT Com (2995471)
writes "About 252 million years ago, cracks in the Earth's crust in Siberia caused vast amounts of lava to spill out and blanket the region with about 6,000,000 cubic kilometers of molten material—enough to cover the continental US at one mile depth — and triggering a huge change in climate that caused a mass extinction event that killed roughly 90 percent of life on earth. Now Helen Thompson writes in the Smithsonian that a team at MIT have focused their efforts on this major extinction event, which marks the end of the Permian period and the beginning of the Triassic period and their results suggest that the die-out happened a lot faster than previously thought. Their initial results suggest that the extinction event spanned 60,000 years, a mere blink of an eye in geological time. The shorter time scale means that organisms would have had less and less time to react and adapt to changes in climate, atmospheric CO2 and ocean acidity. Failing the ability to adapt, they died. Other mass extinction events have also been narrowed down to short timeframes. The asteroid impact that killed the dinosaurs at the end of the Cretaceous period only took about 32,000 years. A similar study of another mass extinction triggered by volcanic eruptions at the end of the Triassic period suggests it lasted less than 5,000 years (PDF). Despite the fact that all of these extinction events were caused by different things, the ecosystem collapse happened very quickly. "Whatever the causes of the extinctions may be, and it looks like there are very different causes for some of them, the biosphere may collapse in very similar ways once it gets beyond a tipping point," says Doug Erwin. Some scientists see the end Permian as a lesson for the 21st century (PDF) and say that understanding the conditions leading up to, within, and after a mass extinction event may help us to avoid human-induced ecosystem collapses in the future. As Erwin puts it, "you don't want to start a mass extinction, because once a mass extinction begins, the prognosis is pretty grim.”"