People on the left are more likely to accept climate change than those on the right in the USA, Australia and much of Western Europe. But it’s a question that starts with little more than a thermometer, a measurement of the temperature at the earth’s surface. Why does a science question divide people along party lines? Was it the oil industry, fuelling doubt about the science? Or something deep in our psychology, that causes us to push the science aside in favour of belonging to a tribe, a feeling that who our friends are and what they believe, matters more? Presenter: Michael Blastland Producer: Phoebe Keane Editor: Richard Vadon