We certainly hope that students will form an opinion, based on the way we have taught them to analyze evidence for themselves, about whether it was more likely natural fluctuation or industrial gas that caused the one degree rise in temperature from 1860 to 2000, and whether that one degree rise has led to havoc in hurricanes, droughts and sea level rise. But the data are weak on all of these questions, and it is not our job to make those judgments for them.