I believe that in every country the first motivator is the economic factor since any project including construction won't be launched if it's not economically viable! This is why governments encourage green projects by reducing the fees or providing loans with zero interest .. another important motivator is the public awareness about environmental issues
In my opinion, it is more of a compulsion than motivation. Water crisis; shortage of energy; waste generation and disposal; and in some cases direction of the Government towards less energy & clean environment; are the factors which are making the people to think differently from the conventional way of constructing buildings and go for GREEN buildings .
Could be different things, here in China clearly the pollution will be a driver but the problem I see is that people do not associate themselves with the problem. Personal carbon footprint etc is still a concept people are unfamiliar with or disassociate themself with.
In Germany on the other hand people are very much aware of their impact but driver/prohibitor is cost. "It costs too much" all too often is the excuse while denying the cost of inaction is even higher in the long run.
While there is different drivers the real question we must ask is why people are different towards the same issue.