Picture: Hurricane Irma passing the eastern end of Cuba. Credit: NASA/CIRA.

Climate change is expected to worsen tropical cyclone hazards, such as extreme rainfall, but there is less certainty in the projections of the overall frequency of tropical cyclones as the climate continues to warm.

CLEX researchers and colleagues used high-resolution climate models, with a 4km resolution, focused on the tropics to explore how the formation and intensification of tropical cyclones responded to a warmer climate.  The computer simulations were designed to capture the full evolution of a tropical cyclone, from a simple cluster of tropical clouds they called a “seed disturbance” right up to a Category 5 hurricane.

To do this they ran a series of 5-member ensemble experiments (25 total) at different sea surface temperatures to test how the formation and intensification rate of cyclones responded to climate warming.

The time to the formation of a tropical cyclone “seed” disturbance, the precursor to a tropical cyclone, revealed a mixed response to surface warming that cannot be explained by simple trend. This highlighted the current uncertainty around the impact of climate change on global and regional tropical cyclone frequency. However, the maximum intensification rate of tropical cyclones increased strongly with warming. This suggests that rapidly intensifying storms may become more frequent in a future warmer climate and the speed of this increase in intensity will continue to accelerate as the world’s oceans continue to warm.

  • Paper: Ramsay, H. A., Singh, M. S., & Chavas, D. R. (2020). Response of tropical cyclone formation and intensification rates to climate warming in idealized simulations. Journal of Advances in Modeling Earth Systems, 12, e2020MS002086. https://doi.org/10.1029/2020MS002086