On your question 1, I would rephrase it to say that human activities tend to cause global temperatures to rise. Or that human activities have caused global temperatures to rise. Otherwise, you get stuck in the whole issue about the "pause," which might show that temperatures are not currently rising for reasons that are not fully understood and are subject to much debate. The paper you cite was from early 2010, and was based on research before that, so the pause had not become much-discussed by then.

One thing that I think will be interesting if you run the quiz is to identify a group who resist polarization and are between the extremes. For example, I think there are plenty of people that agree that carbon dioxide causes temperatures to rise (all else being equal) but believe that the feedback loop is not significantly positive. People from each extreme tend to lump them middle-grounders in with the people at the other extreme: "You're an alarmist!" "You're a denier!" etc.