It seems that you are one of the very few who did not know this. And this is only one link, there are others. You would need to read how the study was conducted to understand fully. Not to hard to find. Google "97% debunked" for a good place to start.

http://climatechangedispatch.com/97-articles-refuting-the-97-consensus/
The 97% “consensus” study, Cook et al. (2013) has been thoroughly refuted in scholarly peer-reviewed journals, by major news media, public policy organizations and think tanks, highly credentialed scientists and extensively in the climate blogosphere. The shoddy methodology of Cook’s study has been shown to be so fatally flawed that well known climate scientists have publicly spoken out against it,

And in all honesty, it's not that I necessarily disagree that man is a contributing factor. It's just that I am suspicious of people telling me things that are known lies and calling me stupid for not believing them.