How does globally accumulated tropical cyclone energy vary in response to a changing climate?

How tropical cyclone (TC) activity varies in response to a changing climate is widely debated. The accumulated cyclone energy (ACE) is one of the indicators of TC activity and has attracted considerable attention because of its close relationship with the damages caused by TCs. Previous studies have focused on detecting long-term trends in global ACE; however, the results are inconclusive. Here, it is revealed that the global ACE demonstrates a striking interdecadal variation over the past four decades, with a historical peak occurring in the 1990s. A close relationship between the interdecadal variability of the global ACE and the Interdecadal Pacific Oscillation (IPO) is also identified, with a Pearson correlation coefficient of 0.75 (P < 0.01). When the IPO is in its positive phase, more TCs with a longer lifetime occur owing to greater coverage of weak vertical wind shear (VWS) conditions over the tropics. The coverage of weak VWS conditions can be verified by either prescribing the observed sea surface temperature in atmospheric models or the observed IPO in coupled models, indicating the significant role of the IPO. Our findings show that the IPO affects the interdecadal variability of global TC activity through moderating atmospheric circulations.