This satellite image provided by NOAA shows Hurricane Florence on the eastern coast of the United States on Friday, Sept. 14, 2018. (NOAA via AP)
WASHINGTON – A warmer world makes for nastier hurricanes. Scientists say they are wetter, have more energy and intensify faster.
Their floods are more destructive, because the climate change has already made the seas rise. And the last time, the storms seem to be stalling more often and thus dumping more rain.
Study after study shows that climate change in general makes hurricanes worse. But the determination of the role of the warming of the earth in a specific storm, such as Hurricane Florence or Typhoon Mangkhut is not as easy — at least not without detailed statistical and computer analyses.
The Associated Press consulted 17 meteorologists and scientists who study climate change, hurricanes, or both. A few experts remain cautious about the attribution of global warming to a single event, but the majority of scientists clearly see the hand of the man in Florence.
Global warming is not caused by Florence, they say. But it makes the system a greater danger.
“Florence is yet another poster child for human-supercharged storms that are becoming more common and destructive as the planet warms up,” said Jonathan Overpeck, dean of the school environment at the University of Michigan. He said that 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 conditions, scientists would refrain from the establishment of 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 the events would be different in a world without human-induced climate change.
A few months after the Hurricane, Harvey, studies found that the warming of the earth can significantly increase the opportunities for Harvey’s record of heavy rainfall.
“It’s a bit like a plot line out “Back to the Future’, where you travel back in time to some alternate reality” that is plausible, but without that man is changing the climate, said University of Exeter climate scientist Peter Stott, one of the pioneers of the field.
A National Academy of Sciences report found these studies generally credible. A team of scientists tried to make a similar analysis for Florence, but outside experts were on their guard, because it was based on projections, not observations, and not enough use of computer simulations.
As the world heats up and science advances, scientists get more specific, even without attribution studies. They cite basic physics, the most recent research about storms and previous studies and put them together for something like Florence.
“I think we can say that the storm is stronger, wetter and more impact of a flooding point of view than it would have been, BECAUSE the man-made global warming,” Pennsylvania State University climate scientist Michael Mann wrote in an e-mail. “And we don’t need an attribution study to tell us that, in my opinion. We just need the laws of thermodynamics.”
Georgia Tech climate scientist Kim Cobb looks not only on the basis of the physics, but all peer-reviewed studies that link climate change to wetter storms.
“We have a solid data about decades of rainfall records nail the attribution — climate change is increasing the frequency of extreme precipitation events,” Cobb said.
Several factors make scientists more confidence in the directing of the climate-change finger in Florence.
For each degree that the air heats up, it can be almost 4 percent more water (7 percent per degree Celsius) and offer significantly more energy throughout the storm, scientists said.
“The amount of water that comes from the hurricanes is definitely one of the most robust connection that we have,” National Oceanic and Atmospheric Administration climate scientist Jim Kossin said.
And to look at Florence in particular, “it is very likely that climate change has warmed the ocean in such a way that the hurricane’s heavy rainfall is more destructive than without the warming of the earth,” said Weather Underground Meteorology Director Jeff Masters, a former hurricane hunter.
The warmer air and water makes storms more intense or stronger, Stott said.
A Kossin study this year found that tropical cyclones — a category with hurricanes and typhoons — are moving more slowly and even stalling. Kossin said: “it happens a lot more than I used to.” Several studies agree that climate change is to blame, but differ slightly in their conclusions.
With the emergence of Florence, in some places in the US is saturated by a stalled hurricane for the fourth year in a row, storm surge expert Hal Needham said.
Kossin and Overpeck also pointed to studies that show that storms are intensifying faster than they are accustomed to.
Just as in Superstorm Sandy, scientists said it is clear that the hurricane storm surge is exacerbated by the rise of the sea level, because the power of 6 to 10 feet of water comes on the top of the seas, which is a lot lower decades ago. An extra 8 inches or so can mean the difference between staying dry or damaged, Masters said.
In the Carolina’s, natural and temporary climate factors added to the “march to the top” of global warning. Because of that, the seas have risen by almost 5 inches in five years, said Andrea Dutton of the University of Florida.
Meteorologist Ryan Maue of weathermodels.com warned that observers “to stick to general trends around the world and not to individual cases.”
University of Miami-hurricane expert Brian McNoldy said there are also a variety of ever-changing factors that make it difficult to the fault of the climate change in particular.
“If you are trying to make climate policy,” Maue said Friday, “you don’t want to make it on a storm by storm basis.”
Follow Seth Borenstein on Twitter: @borenbears . His work can be found here .
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For the latest news on Hurricane Florence, visit https://www.apnews.com/tag/Hurricanes .