2 degrees is bad enough, 4 would be horrendous

Mark Lynas: Why we must heed Bob Watson's climate change warning | Comment is free | guardian.co.uk: "the latest science shows that even two degrees is not good enough, never mind four. And since four degrees would be a catastrophe that many of us, or our children, would not survive, it is surely our absolute duty to do everything in our power to avoid it."