Reuters: The old adage, "it's not the heat, it's the humidity," will come into play more often and in more places because of climate change, with life-altering results in southern U.S. cities from Miami to Atlanta to Washington and even northern ones such as New York, Chicago and Seattle. "As temperatures rise, toward the end of the century, less than an hour of activity outdoors in the shade could cause a moderately fit individual to suffer heat stroke," said climatologist Robert Kopp of Rutgers University,...