  Rapid intensification (RI) is likely the most crucial contributor to the
development of strong tropical cyclones and the largest source of prediction
error resulting in great threats to life and property, which can become more
threatening with proximity to landfall. While enormous efforts have been
devoted to studying the basin-wide fluctuation, temporal-spatial variations of
global RI events remain uncertain. Here, we show that, compared with open
oceans where the annual RI counts do not show any significant change, the
coastal offshore regions within 400 km from the coastline host significantly
more RI events, with the RI count tripled from 1980 to 2020. Reasons
responsible for the coastal RI occurrence are analysed, with the dominant
large-scale environmental factors identified. This work yields an important new
finding that an increasing threat of RI in coastal regions has occurred in the
preceding decades, which may continue in a future warming climate.
