What issues are there with that paper?

But I would say that it's worth noting there is criticism of the original paper http://iopscience.iop.org/article/10.1088/1748-9326/11/4/048....

But as I said you've changed my mind, the 97% figure seems to be accurate.

The “97 percent” statistic first appeared prominently in a 2009 study by University of Illinois master’s student Kendall Zimmerman and her adviser, Peter Doran. Based on a two-question online survey, Zimmerman and Doran concluded that “the debate on the authenticity of global warming and the role played by human activity is largely nonexistent among those who understand the nuances and scientific bases of long-term climate processes” — even though only 5 percent of respondents, or about 160 scientists, were climate scientists. In fact, the “97 percent” statistic was drawn from an even smaller subset: the 79 respondents who were both self-reported climate scientists and had “published more than 50% of their recent peer-reviewed papers on the subject of climate change.” These 77 scientists agreed that global temperatures had generally risen since 1800, and that human activity is a “significant contributing factor.”