UN IPCC Lead Author Dr. Hans Von Storch: CO2-caused warming only an ‘assumption’ — other factors could be ‘underestimated’
'For outsiders it always looks a bit like us climate scientists jump to any explanation that doesn’t go against our basic assumption – that CO2 is behind global warming. I do believe that this basic assumption is right, but it could also be that there are other factors we’ve underestimated so far.'