And even if all that is wrong, if we act we end up with cleaner sustainable future. 

It is always prudent to take the worst scenario into consideration.  Better safe than sorry.  We all wear our seat belts "just in the case' we have an accident.  I have been driving for many decades, some years clocking as much 100 000 km, all these years I only had 2 accidents, yet I do up my belt every time I get into a car.