Trends in tropical cyclone intensity

A study suggests that tropical cyclones (TC) have been increasing in intensity over the past four decades. Theory and models suggest that tropical cyclone (TC) intensity tends to increase with global mean surface temperatures. However, such a trend is difficult to detect in observations due to spatial and temporal heterogeneities in the instrumental record. To increase the confidence in the trend extracted from observations, James Kossin and colleagues extended an existing globally homogenized record of satellite imagery to encompass the period 1979-2017. The record had previously covered the years 1982-2009 and exhibited increasing trends in global TC intensity, but the trends were not statistically significant. The authors found that the probability of a hurricane having wind speeds of at least 100 knots increased by approximately 15% between the early and latter halves of the 39-year record. This finding corresponded to a statistically significant rate of increase of approximately 8% per decade. A time series of the proportion of all hurricanes exceeding 100 knots exhibited a similar increasing trend of approximately 6% per decade. The results are consistent with the predictions of physical theory and numerical simulations and increase confidence in the view that TCs have become stronger under global warming, according to the authors.

Article #19-20849: “Global increase in major tropical cyclone exceedance probability over the past four decades,” by James P. Kossin, Kenneth R. Knapp, Timothy L. Olander, and Christopher S. Velden.

MEDIA CONTACT: James P. Kossin, National Centers for Environmental Information, National Oceanographic and Atmospheric Administration, Madison, WI; tel: 608-265-5356; e-mail:

[email protected]

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