"But global warming isn't the only factor. Phoenix, the hottest city in the United States, is a classic illustration of another reason experts expect more killer heat waves". "It's called the "urban heat island" effect." "As cities grow, more of the landscape gets covered by pavement and buildings. They soak up the sun's heat all day long and radiate it during the night. Not only do people get no respite from the heat, it means the next day gets off to a hotter start. So temperatures are even higher in the afternoon." How Extreme Heat Affects the Human Body "Amazingly, humans can adapt to this kind of blast-furnace heat – within limits. If you live in heat like this for just a few weeks, your body undergoes some remarkable changes." http://www.npr.org/templates/story/story.p...toryId=12744487
