Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment

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Science  16 Sep 2005:
Vol. 309, Issue 5742, pp. 1844-1846
DOI: 10.1126/science.1116448
Fig. 4.

Intensity of hurricanes according to the Saffir-Simpson scale (categories 1 to 5). (A) The total number of category 1 storms (blue curve), the sum of categories 2 and 3 (green), and the sum of categories 4 and 5 (red) in 5-year periods. The bold curve is the maximum hurricane wind speed observed globally (measured in meters per second). The horizontal dashed lines show the 1970–2004 average numbers in each category. (B) Same as (A), except for the percent of the total number of hurricanes in each category class. Dashed lines show average percentages in each category over the 1970–2004 period.