Question: If I add heat to something, how much does the temperature rise? Answer: It depends.
If you add heat to ice water, you melt ice, but the temperature remains constant until all the ice is gone. The same amount of heat that would raise the temperature of a kilogram of water by 1ºC would, if delivered rapidly, easily be enough to set a tree leaf on fire. If heat were added to a rocky surface, the surface temperature would depend on how much heat would be re-radiated and how much heat would be conducted through the rock to the cooler ground beneath it. Heat added to a square meter of a puddle would have an entirely different effect than the same amount of heat added to a square meter of ocean water.
Therein lies the problem with climate models that attempt to estimate temperature rise due to increases in CO2 and H2O, or more specifically to increases in heat retention due to those greenhouse gases. You can get anything you want.
There are, however, some unambiguous simplifications that arise from simply asking answerable questions.