Yes, Stone Age practices were too weak to have much effect. My objection is only to the notion that primitive societies were somehow more enlightened than modern societies. They weren’t; they were just too weak to do any damage. Of course, we know better, and that only makes our stupid actions all the more reprehensible.
Do you know anything about the outcome of those three environmental research projects funded by the climate science deniers? There have been a number of cases in which climate science deniers funded projects that ended up contradicting the claims of the deniers. The most striking of these was a project some years back at the University of California, Berkeley. The researcher was skeptical about the claims of climate science, and sought funding to carry out a rigorous study of one aspect of the science. He got a ton of money, carried out the research, discovered that in fact the climate science was right on the nose, and that the deniers were wrong. He declared himself convinced, and published his results in the scientific literature.
Or perhaps the funded research as a public relations project. Perhaps something about saving puppies or bunnies. It would definitely be interesting to learn how all that came out. 😛