I don’t think we have conclusive proof that humans are at the center of [global warming]
![I don’t think we have conclusive proof that humans are at the center of [global warming]](http://cdn.quoteddaily.com/images/newt-gingrich/i-dont-think-we-have-conclusive-proof-that-humans-are-at-the-center-of-global-warming.jpg)
I don’t think we have conclusive proof that humans are at the center of [global warming]