Stephan: By 2050 cities like Phoenix, Austin, and San Antonio will be having 150 days a year with temperatures over 104°F -- some projections say daily temperatures of 120° will make up much of the summer months. That plus a growing lack of water doom these cities at least in their present size and configuration.
Heat and humidity are climbing in many of the most populous U.S. cities, and the perilous trend will continue through 2050 (see graphic to left). Heat is the top weather killer. Interactive graphics about increasing “danger days” can be found in a sweeping new report by Climate Central.
