Disaggregating the Increase in Tropical Cyclone Intensity in Kossin et al. (PNAS 2020)

TL;DR

This paper analyzes the increase in tropical cyclone intensity over four decades, highlighting that the relative rise is most notable in category 3 cyclones and that measurement limitations may influence these findings.

Contribution

It disaggregates the observed increase in tropical cyclone intensity, emphasizing the role of measurement power and providing detailed insights into category-specific trends.

Findings

Category 3 cyclones show the highest proportional increase.

Category 5 cyclones exhibit the greatest proportional decrease.

Measurement error and rarity influence observed intensity trends.

Abstract

Kossin et al. (2020) successfully test (over the last four decades) the prediction of climate-change models that conditional tropical cyclone intensity (the frequency of major [category 3-5] cyclones divided by the frequency of all cyclones) should increase. Yet, the highest relative proportional increase in incidence occurred in category 3 cyclones. The highest relative proportional decrease occurred in category 5 cyclones. This inference is not due to different treatment of measurement error. It is plausibly due to lower power for relatively rarer category 5 cyclones.