Arguments about climate change are rife with conspiracy theories. There are those who think the whole thing is a giant hoax: a scam cooked up by environmentalists and left-wing scientists to empower governments and rip off consumers. But there are equivalent suspicions on the other side: a belief that the sceptics and denialists are just the front for an oil industry-funded plot to bamboozle voters and keep the fossil fuels flowing. The prevalence of these kinds of conspiracy theories is one reason why the debate has become so fractious and polarised. This talk will explore why the climate debate seems so susceptible to conspiracy theories and what that tells us about the current state of mistrust in democracy: mistrust of experts, mistrusts of corporations, mistrust of government itself. Why on an issue like this – of such enormous importance – do we find it so hard to believe what we are told?