My usual quibble with the scare quotes at the end:
'climate change impacts [will likely] be so severe they go beyond the limits of what nations can adapt to ... the difference between two degrees and four degrees [of global warming] is human civilisation ... In other words, we are potentially talking about the end of human life as we know it'
Dave C says that like it would be a bad thing! Point being that 'human life as we know it' (esp. in the affluent west) is totally different to how our species has lived for +/-99% of our history, and life without nations and this uncritically lauded 'civilisation' could in fact be considerably better for us and the planet as a whole. Not to downplay the immense amount of suffering that likely lies between here & there (and if it leads to extinction then it's a moot point!), but it seems clear to me that collapse is the only way out of this mess, and the sooner it happens the quicker we can all begin to recover from this nightmare...