Pollution during the 20th century appears to have suppressed North Atlantic hurricanes
The Clean Air Act, which has benefited breathing in many American cities over the last few decades, may have worsened the weather in some places.
New climate simulations suggest that reducing the level of atmospheric aerosol particles produced by human activity might have been the main cause of a recent increase in tropical storm frequency in the North Atlantic.
Aerosol levels have increased since the industrial revolution began, but there have been periods when emissions stalled or fell, such as the Great Depression, World War II and after clean air legislation was enacted in Europe and the United States in the 1970s and 1980s.
The climate simulations suggest that these periods of low emissions eventually increased tropical storm frequency. “It seems the Clean Air Act in particular has led to an increased number of hurricanes over the last decade or so,” says Doug Smith of Met Office Hadley Centre in England, a coauthor of the research published