Home Sciences The fall in pollution in Europe since 1980 favors more violent hurricanes

The fall in pollution in Europe since 1980 favors more violent hurricanes

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Surprisingly, cleaner air in Europe and North America is generating more hurricanes in the Atlantic, as shown by a study promoted by the US government, specifically by the National Oceanic and Atmospheric Administration (NOAA). This finding concludes that a 50% decrease in particulate pollution in Europe and the US is associated with a 33% increase in Atlantic storm formation over the past two decades. In contrast, in the Pacific exactly the opposite happens, with more pollution and fewer typhoonsAccording to the study, published in Science Advances Few days ago.

NOAA hurricane scientist Hiroyuki Murakami ran numerous climate computer simulations to explain changes in storm activity in different parts of the world. These changes cannot be explained by natural climate cycles and found a relationship with aerosol pollution from industry and automobiles.. These aerosols are sulfur particles and droplets suspended in the air that make it difficult to breathe and see.

Scientists have long known that aerosol pollution cools the air, sometimes reducing the larger effects of greenhouse gases from burning fossil fuels. Previous studies have already seen this as a reason for the increase in storms in the Atlantic, but Murakami has found a more direct explanation.

Hurricanes need warm water, which is heated by the air, as the ‘fuel’ that drives them and are harmed by wind ‘shear’, which changes into upper-level winds and can ‘decapitate’ storm tops. Cleaner air in the Atlantic and dirtier air in the Pacific, due to pollution in China and India, affect both phenomena, Murakami said.

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In the Atlantic, pollution has decreased since 1980

In the North Atlantic, aerosol pollution peaked around 1980 and has been steadily declining ever since. That means the cooling that was masking some of the warming from greenhouse gases is wearing off, so sea surface temperatures are rising even more, Murakami explained.

Besides that, the lack of cooling aerosols has helped push the jet stream (the air current that moves weather from west to east in a roller-coaster-like route) further northreducing the ‘shear’ that had been dampening hurricane formation.

“That’s why the Atlantic has gotten pretty crazy since the mid-’90s and that’s why it was so quiet in the ’70s and ’80s,” said climatologist and hurricane scientist Jim Kossin of insurance firm The Climate. Service. Aerosol pollution ‘gave a lot of people a break in the ’70s and ’80s, but now we’re all paying for it“, he added.

There are other factors in tropical cyclone activity, related to La Niña and El Niño, natural fluctuations in temperatures in the equatorial Pacific that alter climate around the world. Human-caused climate change due to greenhouse gases, which will grow as reductions in aerosol pollution level off, also influence long-term natural climate oscillations, Murakami said.

Climate change caused by greenhouse gases is expected to slightly reduce the total number of storms, but increase the number and strength of the most intense hurricanes.make them wetter and increase storm surge flooding, Murakami, Kossin and other scientists explained.

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Cyclones will increase in the Atlantic

While the cooling due to aerosols is one-half to one-third smaller than the warming caused by greenhouse gases, it is about twice as effective in reducing the intensity of tropical cyclones as increasing the warming, said Adam Sobel, a climate scientist at Columbia University.

As aerosol pollution remains low in the Atlantic and greenhouse gas emissions rise, the impact of climate change on cyclones will increase in the future and become more prominent, Murakami said.

Meanwhile in the Pacific, aerosol pollution from Asian nations increased 50% between 1980 and 2010 and is now beginning to decline. Tropical cyclone formation between 2001 and 2020 has turned out to be 14% less than between 1980 and 2000, Murakami said.

Murakami also found somewhat different implications when studying what happens further south. A drop in aerosol pollution in Europe and the United States changed global air patterns in such a way that storms in the southern hemisphere, specifically around Australia, decreased.

Pollution kills more than hurricanes

But while more Atlantic hurricanes may be a problem, the deaths caused by these phenomena cannot be compared with the seven million people who die every year worldwide due to air pollutionrecalled Kristie Ebi, a professor of public health at the University of Washington.

“Air pollution is one of the leading causes of death, so reducing emissions is critical, no matter what happens to the number of cyclones,” Ebi said.

Reference study: https://www.science.org/doi/10.1126/sciadv.abn9493

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Environment section contact: crisisclimatica@prensaiberica.es

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