I believe that if you can't stop one of the causes of global warming, you can indeed try to stop the other.

Stupid question: does mankind have the kiloton capacity and engineering skills to shift the Earth's orbit by a tad bit, to cool it off? (without sending us all to hell prematurely). Wait, I know the answer to that one: we fail to land most probes on Mars, why on Earth would we think we're capable of pulling off a stunt like that?