Research Suggests Cleaner Air Brings More Storms

August 23, 2013- Could it be that pollution suppressed North Atlantic hurricanes during the 20th century?

ScienceNews reports on research that suggests The Clean Air Act, which has improved breathing in American cities over the last few decades by reducing the level of atmospheric aerosol particles, may have been the primary cause of a recent increase in the number of tropical storms in the North Atlantic.

They write, "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 June 23 in Nature Geoscience."

Whether derived from burned fuels or from volcanoes and dust, aerosols reflect some of the sun's energy and seed brighter, more long-lived clouds, thereby cooling the Earth's surface. Hence, in the past higher levels of aerosols may have cooled the surface of the North Atlantic and shifted the air currents responsible for hurricane formation.

ScienceNews quotes Smith, "In the 20th century, aerosols probably had more effect on storm frequency than did greenhouse gases like carbon dioxide" and points out that, once created, greenhouse gasses persist for many decades while aerosol particles stay in the atmosphere for only the short timespan of a few weeks.

They write, "The simulations suggest that by the end of the 21st century, greenhouse gases will reduce tropical storm frequency once more. 'But in the near future, further improvements in air quality may lead to even more storms,' Smith suggests.

He cautions, though, that atmospheric aerosols’ effects on storms are not a good reason to let them increase again because they are hazardous to human health. 

“We don’t want to give the impression pollution is a good thing,” he says. Other researchers have suggested that decreased aerosols helped end the drought that devastated the Sahel region of Africa in the 1980s."

Read the full post here. The published research is available for purchase online here.

Carnow Conibear and Associates is a demonstrated leader in the occupational and environmental health professions since 1975. To find out more, click here or call us at (800) 860-4486.