Air pollution is certainly bad for our health and the environment’s health, but it has one unexpected benefit: reducing the frequency of hurricanes. A new study published in Nature Geoscience suggests that heavy particle matter, such as smog from coal-burning plants and oil refineries, may have had a mitigating effect on hurricane activity around the northern Atlantic throughout most of the twentieth century.
The study, authored by researchers in the Met Office, the United Kingdom’s public climate and weather research agency, analyzed simulations of Atlantic weather patterns covering the time period of 1860 to 2050. It concluded that when air pollution increased, there were fewer hurricanes.
The study authors attribute this dampening effect on hurricanes to the pollutants blocking some sunlight from reaching the ocean’s surface, and consequently the water temperature not rising as quickly. Warming water is one of the key components to hurricane formation.
According to Nick Dunstone, a Met Office climate prediction scientist the study’s lead author, industrial pollution coming from Europe and North America cooled the northern Atlantic relative to the ocean’s other regions. And this had the effect of making that northern zone less conducive to hurricanes.
But when global efforts to clean up air pollution got under way in the 1980s, they may have had an unfortunate side effect: more hurricanes. The researchers saw an active hurricane period pick up in 1995 and continue to the present day. The time periods of 1900-1920 and 1970-1980 were also active periods for hurricanes.
Don’t take this study to be an endorsement of air pollution, however. The researchers credited anti-air-pollution measures with improving human health overall and with restoring stable rainfall in Africa’s Sahel region, which had been suffering from devastating droughts in the 1980s.
The key takeaway from these findings, according to the researchers, is the role that knowledge of air pollution can play in forecasting hurricane activity in the future. It suggests that the frequency of Atlantic hurricanes over the next few decades will depend to some degree on future air pollutants and their interactions with the natural cycles of the Atlantic Ocean region’s wind and weather.
It’s also worth noting that, as other studies have indicated, fewer hurricanes doesn’t necessarily mean less hurricane damage. According to analyses of the last few decades of hurricane activity by the U.S. National Oceanic and Atmospheric Administration, the percent of hurricanes that exhibit Category 4 or Category 5 winds—the highest rating for wind speed—has been increasing, a possible effect of the planet’s long-term climate warming.