New research has uncovered unsettling climate-change-induced trends in hurricane intensification.
The research compared hurricane intensification rates between two time periods, the 20 years from 1971 through 1990 vs. 2001 through 2020, and found these observations:
- Hurricanes now intensify in 24 hours to a level which used to require 36 hours.
- The number of hurricanes that intensify from Category 1 (or lower) into a major hurricane (Category 3 or higher) within 36 hours has more than doubled.
- The probability of a system intensifying to ≥ 50 knots within 24 hours is 2.8× more likely now, and within 36 hours is 1.9× more likely now.
- The probability of a system intensifying to ≥ 65 knots within 24 hours is 4.9× more likely now, and within 36 hours is 3.9× more likely now.
One example the paper singles out is hurricane Maria (from 2017) which strengthened from a tropical storm to a Category 5 hurricane in just over 48 hours. Winds increased from a near-gale of 30 knots to an astounding 145 knots in only 60 hours!
Update: Just after writing, hurricane Otis intensified from a tropical storm to a Category 5 hurricane in a mere 24 hours. “Otis was the first Pacific hurricane to make landfall at Category 5 intensity,” according to Wikipedia.
Other recent research suggests that:
- The intensity and the proportion of the most intense storms is increasing.2
- The area of the tropics is increasing at a rate of approximately 0.5 – 1.0° latitude per decade.3 (More warmer water, which fuels cyclones.)
- The average latitude at which tropical cyclones achieve peak intensity is moving pole-ward at rates of 53 km per decade in the Northern hemisphere, and 62 km per decade in the Southern.4 (Cyclones being fueled further toward the poles means larger areas of cyclone activity.)
- The human influence on North Atlantic sea surface temperatures in 2020 was estimated to be in the range of 0.4 – 0.9 °C, with an average of about 0.6 °C.5
What can sailors do in this era of climate change and rapidly evolving weather conditions?
- Garner, A.J. Observed increases in North Atlantic tropical cyclone peak intensification rates. Sci Rep 13, 16299 (2023). https://doi.org/10.1038/s41598-023-42669-y
- Knutson, T., and Coauthors, 2019: Tropical Cyclones and Climate Change Assessment: Part I: Detection and Attribution. Bull. Amer. Meteor. Soc., 100, 1987–2007, https://doi.org/10.1175/BAMS-D-18-0189.1
- Lucas, C., Timbal, B. and Nguyen, H. (2014), The expanding tropics: a critical assessment of the observational and modeling studies. WIREs Clim Change, 5: 89-112. https://doi.org/10.1002/wcc.251
- Kossin, J., Emanuel, K. & Vecchi, G. The poleward migration of the location of tropical cyclone maximum intensity. Nature 509, 349–352 (2014). https://doi.org/10.1038/nature13278
- Reed, K.A., Wehner, M.F. & Zarzycki, C.M. Attribution of 2020 hurricane season extreme rainfall to human-induced climate change. Nat Commun 13, 1905 (2022). https://doi.org/10.1038/s41467-022-29379-1
Image courtesy NASA.