Honestly, I don't care if humans have effect on global warming or not.
Instead, I rather treat the earth as if we do have an impact, and attempt to do as little damage as I can. I'm not going to waste my time with lobbyists and scientists.
I don't go out of my way to buy organic, but I do buy local. There are enough small farms nearby where I can get my dairy, eggs, and meats direct from the farm.
I try to use as few harsh chemicals as I can, and reduce waste. I recycle when I can (we don't have a very good program here) and generally just try to not over-consume.
I don't buy into things that say "green" on the label, and I'm not going to waste my money on a hybrid car (that uses an INSANE amount of energy to manufacture -- moreso than my Bronco), but I do try to do my part.
Spastic Dove hit the nail on the head with this post.
I do buy a decent amount of organic products - mainly because I work in a natural grocer (and get a discount, lol) however, I do not say "No" to a product just because it is not organic. Buying locally and/or fair trade is more important in the long run, for everyone.
The biggest thing when it comes to products that claim to be "natural" or "green" is to do research on the company if it's something you truly care about, so that you are not buying hogwash. There are a decent amount of great companies out there that are really making an honest effort to be responsible on all fronts (humanity, environmental, etc) that are worth supporting. You just have to weed out the bad ones.
One thing that I do try to stay natural with is things like cosmetics, soaps, etc. Personally, I have found that these products work way better for skin, hair, etc. when compared to drug store varieties - but again, that may not be the same for everyone.