Is he serious? The same people who say we (the USA) don't need environmental regulations because voluntary  actions within the "free market" system will take care of everything, turn around and deride the Paris Accords because they voluntary. Science hasn't ever provided absolute certainty but we rely on its best assessment to make policy decisions all the time. The main driver behind climate deniers is greed. They don't want to give up status quo profits and are more than willing to pass the costs of inaction onto future generations. Our grand children are going to be really pissed at our stupidity and greed.