claim: ( 2009 ) have demonstrated recently  – the upper troposphere ( the only place where adding CO2 to the  atmosphere could make any difference to temperature ) is considerably  drier than the models are tuned to expect.
evidence: If the upper air is warmer than predicted by the adiabatic lapse rate (  d S  /  d z > 0 { \displaystyle dS / dz>0 }  ), then when a parcel of air rises and expands, it will arrive at the new height at a lower temperature than its surroundings.