This video is a critique of catastrophic man-made global warming theory, based on presentation slides used in a series of public presentations and debates in late 2009 and early 2010. While the world has almost certainly warmed since the end of the Little Ice Age in the early 19th century, and while it is fairly clear that CO2 and other greenhouse gasses may be responsible for some of this warming, climate alarmists are grossly overestimating the sensitivity of climate to CO2, and thus overestimating future man-made warming. While the theory of greenhouse gas warming is fairly well understood, most of the warming, and all of the catastrophe, in future forecasts actually comes from a second theory that the Earth's climate system is dominated by strong positive feedbacks. This second theory is not at all settled and is at the heart of why climate models are greatly over-estimating future warming. Duration 90:37.