It’s not “chemistry”, it’s just plain chemistry. Yes the earth has gone through cycles, every planet does. Usually the cycles aren’t abrupt and occur over tens of thousands if not hundreds of thousands of years. That is all fact… and has nothing to do with the current artificial increase in greenhouse gasses. It’s all measurable, the ppm of various particles in the atmosphere, the ocean temps and levels, glacial melt, change in bird migration patterns, extreme algae blooms, and on and on.
I understand it’s healthy to be skeptical, especially in the science field. The problem is that if you start with disqualifying standards (like accurate temperature recordings over the lifespan of the earth, like who would ever believe that’s achievable?) then you’ve already made up your mind.
Also, the line I keep hearing about the “grift” sounds an awful lot like calling out an actual budding American industry (something we are in short supply of right about now) for using practices that every other dirty American industry does (and then some). There is no conspiracy here, it’s just a lot of fossil fuel money being thrown into propaganda to create talking points against renewables.
In the end, we all know we have to reach totally renewable energy sources anyway, why not push toward that end? I’ll tell you why, because Americans are procrastinators. We do it in healthcare, in finance (personal and business), in politics, in just about every aspect of life. A “put it off till later” attitude. “Why do I have to worry about it, I’ll be dead?” I hear that crap all the time. What happened to planting the seed of a tree whose shade you’ll never sit under?