Shortened intensification duration offsets the increase of tropical cyclone lifetime maximum intensity

The bimodal distribution of tropical cyclone (TC) lifetime maximum intensity (LMI) has strengthened in recent decades, yet the mechanisms underlying this distribution and its recent changes remain debated. Here, we introduce a rate-duration framework that decomposes LMI into two fundamental components: mean intensification rate and intensification duration. Using global observations, we show that intensification duration is closely tied to genesis locations, and has decreased by 1.4 h per decade (3.4%) during 1982–2023, primarily due to poleward and landward shifts in genesis. This shortening suppresses TC intensification, offsetting nearly half (48.7%) of the rate-induced increase in strong TCs. High-resolution climate models corroborate these findings, revealing that future warming further shortens intensification duration, partially counteracting the increase of LMI. Our results highlight the importance of timescale constraint on TC intensity, providing a quantitative attribution of the competing roles of rate versus duration in shaping LMI and its response to warming.