November 1st, 2024
Key Findings
- Reductions in anthropogenic aerosols from Europe since 1980 likely contributed to fewer tropical cyclones in the South Indian Ocean, while reductions from the U.S. led to fewer tropical cyclones in the South Pacific.
- Elevated aerosols from India since 1980 might notably decrease western North Pacific tropical cyclones.
- Increases in greenhouse gases will primarily drive the decrease in tropical cyclone frequency across the tropics toward the end of this century, with minimal effects from aerosol changes, according to the SPEAR future projections.
Hiroyuki Murakami. Geophysical Research Letters. DOI: 10.1029/2024GL110443
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.
