a. Not a climate denier
b. I never said anything like you are referring to. I never inferred that since its cooling, climate change shouldn't be believed.
c. What I AM saying is the earth's temperature has swung in both directions in a fairly cyclical manner for thousands of years before heavy industry. The earth's temperature warmed when there weren't ANY humans on the planet.
Even going back some 1.2 milion years, scientists still are not sure what caused the change:
"The Mid Pleistocene Transition is a most important and enigmatic time interval in the more recent climate history of our planet," says Fischer. Earth's climate naturally varies between times of warming and periods of extreme cooling (ice ages) over thousands of years. Before the transition, the period of variation was about 41 thousand years while afterwards it became 100 thousand years. "The reason for this change is not known."
https://www.sciencedaily.com/releases/2013/11/131105081228.h...
I would also add the Clean Air Act has done a ton to improve the US and the amount of pollution they contribute.
https://www.epa.gov/clean-air-act-overview/progress-cleaning...
We as a country can do a lot, but what about other developing countries? What are they doing to help reduce pollution and greehouse gases? If we're doing all we can, and other countries aren't following suit, then our gains become minimal and the march towards this catastrophe will continue, unabated.