It is by now a familiar story: The storm hits, the cities flood, dramatic rescues ensue to save people from the rising waters, followed by the arduous and expensive cleanup. But chances are you’ve thought less about the deadly and economically destructive consequences of a slower-moving culprit: drought. Repeated droughts around the world are destroying enough farm produce to feed 81 million people for a year and are four times more costly for economies than floods, the World Bank found in a new study.