America’s signature anti-air pollution law may be behind an apparent surge in the frequency of hurricanes, according to a new paper published in the journal Nature Geoscience.
The study suggests that the decline of aerosol particles due to the anti-pollution law may have increased the frequency of storms in the North Atlantic region by reducing the amount of cooling of the ocean. Hurricanes tend to strengthen when passing over warmer waters.
“It seems the Clean Air Act in particular has led to an increased number of hurricanes over the last decade or so,” Doug Smith of Met Office Hadley Centre in England told the Washington Post Monday.
The Post story notes that while aerosols are associated with man-made emissions, they are also naturally occurring and can come from things like volcanoes and sea spray. They reflect solar energy away from the earth and are associated with increased cloud cover.
The study suggests the decline in those particles is responsible for the increased storm activity and this can be traced to the Clean Air Act. Prior periods of increased storm activity have correlated with periods that also had significant emission declines, such as the Great Depression, when industrial activity fell off sharply.
A 2009 study by Clemson University researchers found that hurricanes had become more frequent in the Atlantic basin region during last century and a half, though the individual storms were not stronger.
Venkatachalam Ramaswamy of the National Oceanic and Atmospheric Administration and Princeton University was impressed by the study, the Post notes, particularly the data on aerosols’ effects on clouds.
Smith cautions though that the study should not be read as a brief for adding aerosol particles into the atmosphere, since they remain unhealthy to breathe. “We don’t want to give the impression pollution is a good thing,” he told the Post.