We do know that if you have a south facing window and an otherwise sealed room, that increasing the insulation value of the room's walls will result in a warmer room. All other things being equal.
Since water vapor is the primary greenhouse gas and water vapor in the earth's atmosphere increases with temperature, any increase in temperature will be multiplied by water vapor.
So if the sun is in a part of its cycle where it is getting hotter, and C02 is increasing, one would expect water vapor to increase also, multiplying the effect.
Considering the politics of China and India, I would say our best bet is to plan for warmer temperatures. I rather doubt that anything we can realistically do will stop whatever is going to happen.