Actual Carbon Emissions vs. IPCC Scenarios - how far away is safety?

[cprise]

8. To what extent do you think we could trigger another Permian extinction?

Dr. Peter Ward has written about how the greatest extinction of all time was triggered by global warming roughly 200m years ago. His description of the devastation seems to hinge on the encroachment of anoxic bacteria in the oceans and how it eventually produced so much H2S gas that the sky turned green (his book on the subject is titled "Under A Green Sky"). The gas is supposed to have killed off a very large proportion of the plants and animals that were otherwise coping with the hotter conditions.

I can't imagine humanity surviving such an event.

Since that past episode of global warming was itself triggered by a surge in volcanism (creating the Siberian traps) I wonder if one significant difference between then and now would be presence of sulfur that the volcanoes/calderas probably added to the biosphere.