Effect of regional anthropogenic aerosols on tropical cyclone frequency of occurrence

Smog can have consequences far beyond the place where it originates. Credit: NOAA

Assessing the impact of anthropogenic climate changes on tropical cyclone activity is of notable scientific and public interest. Since 1980, human-made aerosol emissions have decreased in Europe and the U.S. but increased in China and India. This study used SPEAR, a climate model developed at GFDL, to explore how regional aerosol changes affect global tropical cyclones.

The author’s findings reveal that while aerosol changes have varied across regions since 1980, these regional differences have influenced global tropical cyclone activity in distinct ways over recent decades. For example, reduced aerosols from Europe possibly decreased cyclones in the South Indian Ocean, while the reduced aerosols from the U.S. decreased cyclones in the South Pacific Ocean. Reduced aerosols from Europe and the U.S. increased tropical cyclones in the North Atlantic to a similar extent. In contrast, increased aerosols from India decreased tropical cyclones in the western North Pacific more significantly compared to increased aerosols from China.

The SPEAR model projects fewer global tropical cyclones by the end of this century due to rising greenhouse gases, with aerosols from Europe and the  U.S. remaining low, and India’s increasing. In essence, while regional aerosol changes shape cyclone patterns in the near term, greenhouse gases will dominate tropical cyclone frequency in the long term.