Climate change: Remote control of tropical cyclones


Natural climate variations, which tend to involve localized changes in sea surface temperature, may have a larger effect - per degree local warming - on tropical cyclone activity than the more uniform patterns of greenhouse-gas-induced warming.

The effect of global warming on tropical cyclone activity is widely debated. It is often assumed that warmer sea surface temperatures encourage more frequent and intense tropical cyclones, but several other factors, such as atmospheric temperature and humidity, also come into play.

Gabriel Vecchi and Brian Soden analysed climate model projections and observational reconstructions to explore the relationship between changes in sea surface temperature and tropical cyclone ‘potential intensity’ - a measure that provides an upper limit on cyclone intensity. They found that long-term changes in potential intensity are more closely related to the regional structure of warming than to local sea surface temperature change. Regions that warm more than the tropical average are characterized by increased potential intensity, and vice versa. This indicates that localized changes in sea surface temperature, such as those caused by natural climate variations, are more effective at altering potential intensity (per degree local warming) than more uniform patterns of warming, such as those expected in response to increasing greenhouse-gas concentrations.

CONTACT
Gabriel Vecchi (NOAA, Princeton, NJ, USA)
Tel: +1 609 452 6583; E-mail: Gabriel.A.Vecchi@noaa.gov