The end-Triassic mass extinction, which wiped out half the planet’s marine life about 201 million years ago, was thought to have been caused by an increase of volcanic activity during the break-up of Pangaea. But, researchers now say that a massive release of carbon into the atmosphere, followed by rapid climate change, was more likely the culprit.
Micha Ruhl and colleagues created a record of carbon isotopes from the waxes of land plants and found that at least 12,000 gigatons of methane was injected into the atmosphere over just 10- to 20,000 years of the end-Triassic extinction. Since the volcanic activity that accompanied the dissolution of Pangaea lasted for at least 600,000 years, the researchers suggest that this short-lived burst of methane was more likely responsible for the mass extinctions.
Changes in vegetation at the end of the Triassic Period also provide evidence of strong warming events and an enhanced global water cycle at the time, they say. Ruhl and his colleagues also say that their findings may help scientists plan ahead, since humans could potentially contribute 5,000 gigatons of carbon or more to the atmosphere if we were to burn all of our known fossil fuel reserves.
This research appears in the 22 July 2011 issue of Science also as a segment in Science’s weekly podcast available from Tuesday, 20 July 2011.
