> This happened when ~5C degree warming from millions of years of the Siberian traps eruptions caused methane hydrates to be released into the atmosphere, triggering another ~5C warming and the greatest mass extinction on Earth, the End-Permian Extinction, also known as "the Great Dying" where 96% of marine species went extinct, and 70% of terrestrial species.
That's a theory for what happened, but as I understand it the cause of this extinction has not been conclusively proved.
Yes, it's the leading theory. That doesn't mean is true, just the most likely explanation for the data we have now.
Hardly anything is "conclusively proved", although theories we can design experiments for are much more robust than theories about historical or geological events where we don't have that luxury.
That's a theory for what happened, but as I understand it the cause of this extinction has not been conclusively proved.