Katharine Hayhoe, a climate scientist at Texas T

Katharine Hayhoe, a climate scientist at Texas Tech University and an author of the report, said even if global warming does not change the number of storms — and, she noted, there could even be fewer hurricanes over all — tropical storms and hurricanes do gain energy from warm water, so the unusually warm water that has accompanied climate change “can have a role in intensifying a storm that already exists.”