Quote from THE-BEAKER:
251 million years ago a mammoth undersea methane bubble caused massive explosions, poisoned the atmosphere and destroyed more than 96 percent of all life on Earth. [1] Experts agree that what is known as the Permian extinction event was the greatest mass extinction event in the history of the world.
And besides, only "70 percent of terrestrial vertebrate species becoming extinct" during that event and that was before we had iPads so I'm sure as a species we will have a much higher survival rate than creatures 250 million years ago.Quote from jprad:
Regarding the methane burp theory:
"However, the pattern of isotope shifts expected to result from a massive release of methane do not match the patterns seen throughout the early Triassic. Not only would a methane cause require the release of five times as much methane as postulated for the PETM,[11] but it would also have to be re-buried at an unrealistically high rate to account for the rapid increases in the 13C/12C ratio (episodes of high positive δ13C) throughout the early Triassic, before being released again several times.[11]"
http://en.wikipedia.org/wiki/Permian–Triassic_extinction_event