Spatially synchronized structures of global hydroclimatic extremes

Abstract Spatially synchronized hydroclimatic extremes—droughts, pluvials and drought–pluvial ‘seesaw’ dipoles—cause impacts far beyond where they occur. Adapting to these concurrent risks requires global-scale assessments that capture both remote and local dependencies, yet current approaches generally assume independence across locations, overlooking critical spatial dependencies that bias risk estimates. Moreover, most research treats droughts and pluvials in isolation, neglecting their antiphase co-occurrences. Here we develop a multilayer event-based complex climate network using a 67-year precipitation reanalysis dataset to analyse global synchronizations of hydroclimatic shocks across 0.66 trillion 0.25° pixel pairs. We find pronounced spatial asymmetries in teleconnected (>2,500 km) synchronizations, dominated by oceanic regions (90% of teleconnection links) and southern mid-latitudes. These spatial asymmetries are both event and hemisphere specific, revealed by our regional bundle analysis of 91 global breadbasket region pairs. Two-thirds of region pairs with significant drought or pluvial synchronization occur within the same hemisphere, while 40% of cross-hemisphere pairs exhibit seesaw synchronizations, affecting at least one-third of their areas. These findings highlight the need for integrated assessments of droughts and pluvials and their interconnections, as traditional agricultural trade practices relying on hemispheric diversification may face growing challenges in a warming, synchronized climate.