Global warming is a complex problem with many causative factors. Certainly human activity contributes greatly to this problem. However, I think it is safe to say that it is not the only contributing factor. Forest fires, volcano eruptions, methane gas emissions, etc. contribute as well. While I think Perry is not the brightest bulb in the political area, I think he may be correct in saying that “To stand up and say that 100 percent of global warming is because of human activity, I think on its face, is just indefensible.”
I think all that mankind can do is limit or eliminate what man has created regarding a causative factor. We can’t do much about factors of which we have little or no control. At least with our present technology. In addition, we must not forget about the pollution/decimation of all of our other natural resources such as water, land, etc.