>>12128296I want to know, what is the evidence that a warming of 1.5C-4C will be catastrophic? Most studies say that if we double CO2 concentration from preindustrial levels of 280ppm to 560ppm in 2060 at current emission rates (currently 408ppm), earth will warm by 1.5-4 degrees celsius.Some studies have the lower bound at just 1 degree celsius. What is the evidence that this will be catastrophic? Earth has been warmer in the past (see Paleocene-Eocene thermal maximum) and life, in particular mammals, flourished. To be precise, it was as much as 12 degrees celsius hotter during that time and it did not lead to a collapse of the biosphere. So that sort of rhetoric strikes me as nothing but hysteria.
