Tropical SST modes provide a unified explanation for global tropical cyclogenesis changes

Abstract Over the past four decades, global tropical cyclogenesis (TCG) frequency has exhibited no trend related to strong interannual variability and uneven regional TCG trends, despite pronounced global sea surface temperature (SST) increases. This study offers new evidence explaining the disparity between the global TCG trend and global warming. Here we show that just three global tropics-wide SST patterns can account for TCG interannual variability in most global ocean areas where TCG is climatologically active. We further find that the warming mode of tropical SSTs explains 77% of global ocean areas observed with significant TCG trends, with the strongest influence in the tropics with robust observed TCG trends. These warming-related TCG trends are associated with a reorganization of the Pacific and Atlantic Walker circulations, which modulates environmental conditions governing regional TCG. These findings reveal how global warming influences regional TCG in an uneven manner, consistent with the mechanisms underpinning interannual variability.