No, its all a gimmick. Nature always changes regardless of our involvement.... But I do think we are using way to many resources which creates unsustainability.
I think it requires extreme arrogance to assume that we as people have that much control over something as big as the earth. The earth will go through it's warm and cool cycles regardless of what we do to the planet. If we abuse the planet too much, it will create an environment that will reject our ability to live on it; but the earth will continue to go on doing it's thing. Aside from the theories of global warming being extremely arrogant by humankind, I don't see any legit science to support the theory.
Just like you said, we can abuse the planet too much that can create an unsustainable planet which is what global warming is about. Everything on earth is connected and us human beings can have significant impact to the earth's environment. Yes we may not have that much control over the earth but we can have that much impact, big enough to cause such a thing as global warming.
Metaphor to explain my meaning: It's like there's a runaway semi truck rolling down a hill, and we try and step in front of it to stop it. Fact is, the truck is gonna run right over us without slowing down. The only thing that happens when we step in front of it is that we get run over. No matter what we do to the earth, it will not be affected by us by any substantial degree, but we can still get ourselves run over depending on how we treat it.
Aside from the theories of global warming being extremely arrogant by humankind, I don't see any legit science to support the theory.