More hurricanes popping up in the Atlantic — because of cleaner air, study finds. Why?
Hurricanes have been ramping up in the Atlantic Ocean — and cleaner air is a factor, a new study finds.
The “surprise result” comes after researcher Hiroyuki Murakami studied hurricane trends in the northern hemisphere over the past four decades. Using models, he examined data from two periods: 1980 to 2000 and 2001 to 2020.
During that span of time, the United States and Europe limited their output of anthropogenic aerosols, which are produced by coal combustion and cement manufacturing, among other sources.
But cutting down on emissions of the potentially harmful substances led to another consequence — more hurricanes.
“Without significant amounts of particulate pollution to reflect sunlight, the ocean absorbs more heat and warms faster,” the National Oceanic and Atmospheric Administration (NOAA) said in a May 11 news release. “A warming Atlantic Ocean has been a key ingredient to a 33-percent increase in the number of tropical cyclones during this 40-year period.”
The warmer conditions also have the potential to move the jet stream. That then impacts wind shears, which the Federal Aviation Administration defines as “change in wind speed and/or direction over a short distance.”
“Weaker winds, in turn, mean that there is less difference between the speed of winds in the lower and upper troposphere or less wind shear,” NOAA said. “With little wind shear, tropical cyclones are able to develop and grow in strength over the Atlantic Ocean.”
The study — published in the journal “Science Advances” — acknowledges that other factors such as greenhouse gases could have contributed to the tropical cyclone changes. It also contends that one of the models used has the potential to underestimate the most intense category 3 to 5 hurricanes.
What could happen in the future?
Despite the study limitations, Murakami predicts we could see stronger hurricanes in the future, too, that the decades ahead could see more impacts from greenhouse gases and that the frequency of such storms could be limited in the Atlantic.
“The projection for the next decades is that human-caused particulate air pollution will remain stable in the North Atlantic and that increased greenhouse gases will become a more significant influence on tropical cyclones,” NOAA wrote. “The projection is for fewer numbers of tropical cyclones, but those that occur are likely to be more intense.”
More immediately, experts predict 2022 will be a busy hurricane season when it kicks off next month. Colorado State University forecasters say the Atlantic could see “19 named storms and nine hurricanes,” The Miami Herald reported in April.
What’s happening in other parts of the world?
While the cutbacks in the United States and Europe are impacting waters in the northern hemisphere, they have had the opposite impact for tropical cyclones in the southern part of the globe.
The limitations were found to contribute to a “decrease in the number of these storms in the Southern Hemisphere.”
Meanwhile, the study also found that growing countries in East and South Asia increased their output of aerosols over the past 40 years. That uptick has led to fewer tropical cyclones in the western part of the northern Pacific Ocean, results show.
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