[thedoc (OP)]

Lee Yott asked the Naked Scientists:
   I am trying to better understand current man made climate change by understanding the Permian Mass Extinction.  I've read that it perhaps took tens of thousands of years for CO2 levels to build up from the Siberian trap eruptions in high enough concentrations to raise global temperatures 4-5 degrees. On NPR the other day a specialist was on talking about the recent Paris climate negotiations and he stated that if we were to stop emissions tomorrow that we will still raise global temp 4-5 degrees by.. I can't remember, the next 50 years? If I'm understanding this right it took humans just over a hundred years to do what took the Siberian trap eruptions tens of thousands of years or more to do? I don't understand this equivalency.. Anyhow, the significance to me is that in regards to the Permian extinction wasn't it that 4-5 degree mark that warmed the oceans enough to release huge stores of methane into the atmosphere, which in turn warmed the planet an!
  additional 5 degrees making a total of a 10 degree global temp rise, at which point almost every living thing parished? What does that 4-5 degree rise even mean? What was that baseline temp of the Permian prior to temp rise compared to now- how would we know it was the same as today's baseline temp? My impression is that the world is talking on and on about CO2 but no one is talking about the methane mark where if we warm the climate just enough nature will automatically bump global temp to a mass extinction level- why do you think this fact is missing from the conversation? 4 out of 5 of the Earth's worst mass extinctions involve the build up of CO2, but do they all also involve methane release? In closing, if we are heading towards a 4-5 degree global temp increase regardless of what we do won't that actially mean a 10 degree temp rise? Are we doomed because of methane release? Why when looking into every extinction event does it state that it takes thousands to millions!
  of years to build up CO2 concentrations to get this 4-5 degre!
 e mark but currently we are talking about decades to hundreds of years? What am I getting wrong/ what am I not understanding? Thank you ~ Lee Yott/Flint, Michigan, United States.
What do you think?

[chris]

We made a programme about mass extinctions last year, which also looked at some of these points.

Give that a look and let me know if that helps.