Clean air is necessary for health, but it contributes to an increase in the number of Atlantic hurricanes

(ORDO NEWS) — Cleaner air in the United States and Europe is spawning more Atlantic hurricanes, according to a new US government study.

A study by the National Oceanic and Atmospheric Administration links changes in regional levels of air pollution around the world to increases and decreases in storm activity.

A 50 percent drop in pollutant particles and droplets in Europe and the US is linked to a 33 percent increase in Atlantic hurricane formation over the past couple of decades, while the reverse is happening in the Pacific Ocean with more pollution and fewer typhoons, according to a study published Wednesday in Science Advances.

NOAA hurricane specialist Hiroyuki Murakami has performed numerous climate computer simulations to explain changes in storm activity in different parts of the globe that cannot be explained by natural climate cycles, and has found a link to aerosol pollution from industry and automobiles – particles and droplets of sulfur in the air, which make it difficult to breathe and see.

Scientists have long known that aerosol pollution cools the air, sometimes reducing the larger impact of greenhouse gases produced by burning fossil fuels, and has been cited in earlier studies as a possibility for increased Atlantic storms, but Murakami has found this factor around the world and a more direct link. .

Hurricanes need warm water – which is heated by air – for fuel, and are harmed by wind shear – changes in upper-level winds that can decapitate the tops of storms. Cleaner air in the Atlantic and dirtier air in the Pacific caused by pollution in China and India disrupt both, Murakami says.

In the Atlantic, aerosol pollution peaked around 1980 and has steadily declined since then. That means the cooling that masked some of the warming from greenhouse gases is fading away, so sea surface temperatures are rising even more, Murakami says.

In addition, the absence of cooling aerosols has propelled the jet stream a river of air that moves weather from west to east in a rollercoaster-like trajectory further north, reducing the shear that has prevented hurricanes from forming.

“That’s why the Atlantic Ocean went almost crazy since the mid-90s and why it was so calm in the 70s and 80s,” said climatologist and hurricane scientist Jim Cossin of risk-taking firm The Climate Service. He did not participate in the study, but said it made sense. Aerosol pollution “gave a lot of people a break in the 70s and 80s, but now we’re all paying the price.”

There are other factors in the activity of tropical cyclones: La Nina and El Nino – natural temperature fluctuations in the equatorial Pacific Ocean, which change the climate around the world – play a huge role.

Another factor is anthropogenic climate change due to greenhouse gases, which will increase as airborne pollution declines, as well as other natural long-term climate fluctuations, Murakami said.

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

While aerosol cooling may be half or a third less than greenhouse gas warming, it is about twice as effective at reducing tropical cyclone intensity as warming is at increasing it, said Columbia University climatologist Adam Sobel, who was not involved in the study. research.

As long as airborne pollution remains low in the Atlantic and greenhouse gas emissions rise, the impact of climate change on storms in the future will increase and become more visible, Murakami said.

In the Pacific, aerosol pollution from Asian countries increased by 50 percent from 1980 to 2010 and is now starting to decline. Tropical cyclone formation from 2001 to 2020 is 14 percent lower than from 1980 to 2000, Murakami said.

Murakami also found a correlation that is slightly different southward. Decreasing levels of airborne pollution in Europe and the Americas have changed the global air pattern in such a way that it has meant fewer storms in the Southern Hemisphere around Australia.

But as big as the number of Atlantic hurricanes is, the deaths from additional storms are nothing compared to the seven million people a year who die from air pollution worldwide, says University of Washington public health professor Christie Eby, who studies health. climate and extreme weather conditions.

“Air pollution is one of the biggest killers, so reducing emissions is critical no matter what happens to the number of cyclones,” Eby said.

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