Ninety-seven percent of scientists agree: Climate change is real, man-made and dangerous. President Obama tweeted that, and it has been repeated by countless others. It is tempting for a politician to claim that 97 percent of experts agree with you. But do they? The 97 percent claim was taken from a study paper by Australian John Cook, Climate Communications Fellow for the Global change Institute at the University of Queensland, and his colleagues, published in the journal Environmental Research Letters in May, 2013. The paper says nothing about the would-be dangers of climate change and it counts the number of...