It just makes sense to me that everything that we put in the air and in the water has an impact. Higher concentrations are noticable. Ever been to LA and seen the air quality out there?
Yes, I am one of the worst offenders because I own a foundry and we make investment castings. Our emissions are miniscule compared to what most people associate with the word "foundry" but we use lots of energy. Energy = C02
I am wondering about your question however, you don't want to give dad a heart attack by disagreeing with him but you seem to be looking for supporting opinions to do so.
Just let him think what he wants. It's easier and wiser than thinking that you have to be right. Learned this from my wife of 33 years.