re: #509 abu_garcia
“There can be”, but the fact that the earth has not already gone through the proposed catastrophes when CO2 was far higher than can be achieved by burning all known fossil fuels is a powerful argument that the feedbacks are negative, not positive and the “tipping points” are not out there.
Catastrophes are relative. They have occurred to many, now extinct, life forms. I don’t know how you want to define them, but I’ll just take a few degrees change within one or two human generations.
Tipping points are just whatever happened, negative feedback or not, at the main “points” on the graph that was linked to.