>even then we have to deal with China and India joining the developed world and what that means for CO2 emissions.
Evidence disagrees. Chinese coal consumption is declining ever so gradually (~1% annually) despite their economy growing as normal. In fact their overall co2 emissions are slowly falling as well. Its an open question whether this is going to continue or if this is just a false peak, but if their commitment to renewable and green energy is a predictor then they may fall below the us emission level relatively soon.