I bought a book a few years ago and I think it is called Climatopolis. The first chapter talks about how major cities in certain parts of the world (focused mostly on the U.S.) are fast becoming super heated islands because of all of the steel and glass and concrete in densely packed over urbanized areas and furthermore, that there will be no escape for the poor and disenfranchised because the asphalt absorbs the heat so night gives no reprieve.