Yale University is the host for this lecture by Christopher Schar from the Institute of Atmospheric and Climate Science. He discusses the relationship of heat waves and changes in climate. Beginning by discussing three historical heat waves, the North American Drought of 1988, the Chicago Heat Wave of 1995 and the Great European Heat Wave of 2003, and how these have impacted scientific perspectives on heat waves. He then discusses the variability hypothesis and provides related climate change scenarios. He concludes his talk by discussing the soil moisture threshold effect and some of the complexities of soil-moisture precipitation feedback.