Tom Levenson talks with author and science historian Naomi Oreskes, about extreme weather: the 5/20 Oklahoma tornado and the social costs of climate change, carbon policy and inaction. Naomi co-authored - with Erik M. Conway - "Merchants of Doubt, How a Handful of Scientists Obscured the Truth on Issues from Tobacco to Global Warming," about Big Tobacco, climate science, the establishment of scientific consensus and the role and character of scientific dissent. Follow @TomLevenson More at http://virtuallyspeaking.us/virtually-speaking-science/