A warmer world makes hurricanes more intense

WASHINGTON — A warmer world makes for nastier hurricanes. Scientists say they are wetter, possess more energy and intensify faster.

Their storm surges are more destructive because climate change already has made the seas rise. And lately, the storms seem to be stalling more often and thus dumping more rain.

Study after study shows climate change in general makes hurricanes worse. But determining the role of global warming in a specific storm such as Hurricane Florence or Typhoon Mangkhut is not so simple — at least not without detailed statistical and computer analyses.

The Associated Press consulted with 17 meteorologists and scientists who study climate change, hurricanes or both. A few experts remain cautious about attributing global warming to a single event, but most of the scientists clearly see the hand of humans in Florence.

Global warming didn’t cause Florence, they say. But it makes the system a bigger danger.

“Florence is yet another poster child for the human-supercharged storms that are becoming more common and destructive as the planet warms,” said Jonathan Overpeck, dean of the environment school at University of Michigan. He said the risk extends beyond the Atlantic Ocean, such as Typhoon Mangkhut, which hit the Philippines on Friday.

For years, when asked about climate change and specific weather events, scientists would refrain from drawing clear connections. But over the past few years, the new field of attribution studies has allowed researchers to use statistics and computer models to try to calculate how events would be different in a world without human-caused climate change.

A couple of months after Hurricane Harvey, studies found that global warming significantly increased the odds for Harvey’s record heavy rains.

“It’s a bit like a plot line out of ‘Back to the Future,’ where you travel back in time to some alternate reality” that is plausible but without humans changing the climate, said University of Exeter climate scientist Peter Stott, one of the pioneers of the field.

A National Academy of Sciences report finds these studies generally credible. One team of scientists tried to do a similar analysis for Florence, but outside experts were wary because it was based on forecasts, not observations, and did not use enough computer simulations.

As the world warms and science advances, scientists get more specific, even without attribution studies. They cite basic physics, the most recent research about storms and past studies and put them together for something such as Florence.

“I think we can say that the storm is stronger, wetter and more impactful from a coastal flooding standpoint than it would have been BECAUSE of human-caused warming,” Pennsylvania State University climate scientist Michael Mann wrote in an email. “And we don’t need an attribution study to tell us that in my view. We just need the laws of thermodynamics.”

Georgia Tech climate scientist Kim Cobb looks not just at basic physics but all the peer-reviewed studies that especially link climate change to wetter storms.

“We have solid data across decades of rainfall records to nail the attribution — climate change is increasing the frequency of extreme rainfall events,” Cobb said.