Tibetan Plateau uplift increased western North Pacific tropical cyclone frequency

Nearly one-third of global tropical cyclones (TCs) form over the western North Pacific (WNP), with severe hazards impacting Southeast and East Asia. TC genesis over the WNP underwent substantial shifts during the Cenozoic, yet the underlying mechanisms remain unclear. Here we show that Tibetan Plateau uplift was crucial in shaping the present-day WNP TC genesis pattern. With the present-day land-sea configuration and sea surface temperature prescribed, Tibetan Plateau uplift from early Eocene to modern elevations accounts for nearly half of the simulated increase in TC frequency between the early Eocene and present day. Mechanistically, Tibetan Plateau uplift generates an eastward-propagating Rossby wave train, enhancing the WNP subtropical high and thereby intensifying the monsoon trough. The amplified moisture supply and reinforced upward motion within the monsoon trough collectively favor TC genesis and intensification. Our findings underscore the pivotal role of High Mountain Asia in the Cenozoic evolution of TC frequency over the WNP. Tropical cyclogenesis over the western North Pacific was largely absent in the Eocene (~55 million years ago) but has increased over time, with Tibetan Plateau uplift acting as a key driver in this evolutionary process via reshaping large-scale atmospheric circulation.