Less Pollution, More Atlantic Hurricanes

An interesting and surprising research result.

Increased concentrations of carbon dioxide and greenhouse gases in the atmosphere are expected to lead to increased tropical cyclone rainfall and hurricane intensity. What is less well understood is how more traditional types of air pollution, such as aerosols, may affect hurricane activity.

A new study published in Science Advances, "Substantial global influence of anthropogenic aerosols on tropical cyclones over the past 40 years," finds that reductions in air pollution in the United States and Europe have reduced tropical cyclone activity in the Southern Hemisphere, but may have actually increased such activity in the North Atlantic.

Here is the abstract:

Over the past 40 years, anthropogenic aerosols have been substantially decreasing over Europe and the United States owing to pollution control measures, whereas they have increased in South and East Asia because of the economic and industrial growth in these regions. However, it is not yet clear how the changes in anthropogenic aerosols have altered global tropical cyclone (TC) activity. In this study, we reveal that the decreases in aerosols over Europe and the United States have contributed to significant decreases in TCs over the Southern Hemisphere as well as increases in TCs over the North Atlantic, whereas the increases in aerosols in South and East Asia have exerted substantial decreases in TCs over the western North Pacific. These results suggest that how society controls future emissions of anthropogenic aerosols will exert a substantial impact on the world's TC activity.

For whatever reason, this study reminded of prior research finding that air pollution levels (and their timing and distribution) has an effect on weekday vs. weekend weather.