[breakyerself]

Even zero and one dimensional ultra simplified energy balance models come pretty close to approximating how much warming we've had based on the amount of co2 we've released.

Global average temperatures are governed simply by the need for incoming energy to be balanced by outgoing energy.

You're confusing the complexity of weather with the complexity of climate. A lot of the value of increasingly large scale, complex, supercomputer based climate models is the spacial resolution to be able to tell people of particular regions how their local climate might be affected. For instance a lot of work is going into understanding how the monsoon season will be affected.