Enigheten är stor när det gäller CO2 egen direkta inverkan på temperaturen. Men det finns nyanser. Här är ett exempel:
"It has been calculated theoretically that, if there are no other changes in the climate system, a doubling of the atmospheric CO2 concentration would cause less than 1 deg C of surface warming (about 1 deg. F). This is NOT a controversial statement…it is well understood by climate scientists. (As of 2008, we were about 40% to 45% of the way toward a doubling of atmospheric CO2.)"
Dr Roy Spencer, GW 101