Hurricane Dorian thrashed the Bahamas for three days, whipping structures with winds as strong as 120 mph and dumping nonstop rain on the low-lying islands. James Kossin, a hurricane and climate expert with the National Oceanic and Atmospheric Administration, said climate change is fueling more of these slow-moving storms. “If we look back over the continental United States, which is where our hurricane data is best, and we look all the way back to the year 1900 to the present, so about 120 year, we see a clear slowdown of 17 percent,” Kossin said. “That’s a long enough period to say that this does not appear to be natural variability.”