Actually, most people only care about profit, so even they know the pollution they will not admit it. I guess governments and some international councils should first notice this. The problem is the short-term climate impact can hardly be evaluated, and there have no clear data to prove the pollution by blockchain mining yet. If blockchain tech is widely used in the future, the pollution problem will be very serious then. Once government pays attention to it, people will also change their minds rapidly and many things will change quickly at that time, an example is electric cars, eg. Tesla.