The theory, largely the work of Kerry Emanuel, a scientist at the Massachusetts Institute of Technology, holds that the temperature difference between ocean and upper atmosphere determines how much a storm intensifies. A bigger temperature difference leads to the release of more energy into the storm.
“The warmer you have the ocean, the bigger the difference,” Dr. Camargo said.
The theory has been reinforced by computer simulations that produce more intense storms with rising ocean temperatures. “We understand the theory behind it, and we have seen it in the models,” Dr. Camargo said.
As for storms producing more precipitation, the Intergovernmental Panel on Climate Change has concluded that human-caused warming has affected the amount of water vapor in the air, and that extreme precipitation events have already increased in many parts of the world. The group’s latest report, issued this week, found that such extreme precipitation will likely further increase if the world cannot limit overall warming to 1.5 degrees Celsius (about 2.7 degrees Fahrenheit).
Dr. Knutson cautioned that while this increase in rain and snow amounts has been seen in extreme events in general, of which hurricanes are a subset, “we haven’t actually seen this in the data for hurricanes yet.” But if a given amount of air flowing into a hurricane carries more water vapor, he said, “that enhances the water supply to the storm so it can create higher rain rates.”
As Hurricane Michael approached land on Wednesday, forecasters warned that the worst damage could come from a storm surge of as much as 13 feet. Florida, both along the Gulf and the Atlantic Ocean, is exceptionally vulnerable to storm surge, with strings of low-lying communities on the coasts and along waterways that are connected to the sea.
Storm surge occurs when winds pile water up as it approaches land, and many factors — including the contours of the seafloor, topography of bays and inlets and the stage of the tide when the surge hits — can affect it. But rising sea levels can have an impact, too.
