Third, the temperature several decades from now is to a large extent already determined by the current energy imbalance, thanks to extra CO2 already in the atmosphere. (grist.org)
The current energy imbalance (just a little less than 1 W / m2) implies that the planet would need to warm by ~ 1 x S / 3.7 ºC to restore an equilibrium, and using the standard climate sensitivity of 3ºC for a doubling of CO2, implies a committed warming of 0.8 ºC or so. (realclimate.org)