Scientists Predict More Intense Hurricanes

MIAMI, FL — While weather researchers are calling for a "near average" or "near or above normal" Atlantic hurricane season this year, there is growing consensus among climate scientists that we should be prepared for more intense storms in the coming years, according to a scientific article written by four climate experts. One of top climate scientists in the United States who authored the article also told Patch that he is calling for the creation of a new Category 6 designation to better reflect nature's most deadly threats.

"In the long term, whether we will see fewer or more tropical cyclones in the Atlantic or in other basins as a consequence of anthropogenic climate change is still much-debated," the four authors penned in an article published in Real Climate. "There is a mounting consensus, however, that we will see more intense hurricanes."

Michael Mann of Penn State Univeristy told Patch Tuesday that he believes the Saffir-Simpson Hurricane Wind Scale should be expanded to include a new Category 6. He noted that a 10 mph increase in sustained wind speeds has the potential to cause 20 percent more damage.

"The scale is supposed to connote risk, and there is no question that the risk from a 190 mph monster storm
is far greater than that for a 157 mph marginal Category 5 storm," said Mann, who serves as director of Penn State University's Earth System Science Center and was selected by TheBestSchools.org as one of the 15 top climate-change scientists in the United States.

"We are seeing a general increase in intensities of these storms, and the risk is increasing," Mann explained. "That needs to be more effectively communicated to the public, and this is one way to help do that."

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Weather researchers at Colorado State University last week downgraded their prediction for a slightly above-average Atlantic Hurricane season in 2018. The university's Tropical Meteorology Project team is now calling for a "near-average" season. In the wake of Subtropical Storm Alberto, the researchers are predicting 13 additional named storms during the upcoming hurricane season that started on Friday. The Atlantic hurricane season runs from June 1 through Nov. 30.

Meanwhile, the National Oceanic and Atmospheric Administration predicted a "near or above normal" hurricane outlook for the upcoming 2018 season. In releasing its annual Atlantic outlook in recent weeks, officials said they anticipate 10 to 16 named storms with winds of 39 mph or higher. Of those, five to nine storms could become hurricanes, including one to four major hurricanes with winds of 111 mph or higher.

Mann and the three other authors of the Real Climate article — Kerry Emanuel of MIT, NOAA climate scientist Jim Kossin and Stefan Rahmstorf of Potsdam University — noted there are other factors that might counter stronger hurricanes. They pointed to possible increases in wind shear that tears hurricanes apart, changes in atmospheric humidity and increases in natural or anthropogenic aerosols.

"Due to global warming, we do not necessarily expect more tropical storms overall, but an increasing number of particularly strong storms in Categories 4 and 5, especially storms of previously unobserved strength," according to the article.

Using data since 1979 — the period when geostationary satellites made it unlikely to overlook any cyclones —researchers said there has been an increase in the strongest tropical storms in most oceanic basins, with the strongest increase observed in North America.

The researchers noted that 2012's Sandy was the largest hurricane ever observed in the Atlantic while Harvey dumped more rain on the U.S. than any other hurricane and Hurricane Irma broke the record for cumulative hurricane energy in the Atlantic with sustained wind speeds of more than 186 mph for 37 straight hours.

Mann added that the existing hurricane categories were created at a time when buildings were not constructed to withstand the same powerful winds as today.

"The argument against introducing another category at that point in the past was that a Category 5 storm causes total destruction so there is no need for a higher category," he told Patch. "Given the improvements in the robustness or construction and infrastructure, that is no longer necessarily true."

Based on the existing classification system, Mann said the new category should start around 185 mph. There is now a 130 mph boundary between Category 3 and 4, a 156 mph boundary between Category 4 and 5, which is based roughly on how intensity varies with wind speed, Mann noted.

Photo by Paul Scicchitano.