Online Athens: The world is steadily heating up as the levels of carbon dioxide and other greenhouse gases accumulate in the atmosphere. But cities are heating up even faster, which could have serious consequences for city dwellers in upcoming years. As heat waves become more common and more intense, the suffering will likely fall hardest on the most vulnerable groups, such as the poor, the elderly and people who work out of doors, University of Georgia climate scientist Marshall Shepherd said this week as a...