Influence of global warming on the rapid intensification of western North Pacific tropical cyclones

The rapid intensification (RI) of tropical cyclones (TCs) associated with global warming is a matter of concern worldwide. This study examines how the RI across the western North Pacific is related to the so-called 'efficiency of intensity' (EINT) environment induced by global warming. The EINT condition has been characterized by a strong anomalous high over an unstable tropical atmosphere, which supports efficient intensification. Here, we show that global warming significantly increases the proportion of RI-experiencing TCs through EINT environment. Global warming explains up to 51.3% of the variation in the proportion of RI-experiencing TCs with 93.0% of that related to EINT. Even the influence of El Niño and Southern Oscillation on the proportion of RI events, though small (16.1%), is mostly through an EINT environment (73.9%). Despite the increasing proportion of RI events among TCs, the number shows no trend over time as the EINT condition inhibits the number of overall TC occurrences. The findings are confirmed by the observational consensus between US Joint Typhoon Warning Center and Japan Meteorological Agency.