Yesterday I saw a brief speech by Leonardo di Caprio imploring people to vote – not for the candidate who ignores science. He was talking about the scientific consensus on global warming and mentioned that 97% of all scientists agree that global warming climate change is a man-made phenomenon. This 97% consensus figure is so compelling, it is only fair to explore where it came from.

Where “97% consensus” comes from

One Margaret Zimmerman conducted an opinion survey in 2008. The “survey” consisted of a two-question online questionnaire sent to 10,257 “earth scientists” (?), of whom 3,146 responded. Continue reading →