One of the possible causes of the great dying - (4) A gigantic oceanic methane release, which may have caused a spectacular 1,000+ degree F transient-spike worldwide
atmospheric combustion event (conceptually similar to a massive sewer gas explosion). Even if the atmosphere did not ignite worldwide, a huge oceanic methane greenhouse-gas release could raise Earth's temperature a deadly ten degrees over a matter of years, which would be added to the global warming effect of huge volcanic CO2 greenhouse gas emissions.