U.S. climate envoy John F. Kerry delivered a dire warning Wednesday on “the mounting costs ... of global warming and of a more volatile climate.” Last year’s tally of “22 hurricanes, floods, droughts and wildfires shattered the previous annual record of 16 such events, and that was set only four years ago,” Kerry told a congressional hearing. “You don’t have to be a scientist to begin to feel that we’re looking at a trend line.”