As one of the major producers of extreme precipitation, mesoscale convective systems (MCSs) have received much attention. In the summer of 2020, large regions of East Asia suffered extensive flooding and damage. Therefore, understanding the long-term changes of MCSs is crucial to gain insights into how extreme weather may change in the context of global warming. Recently, MCSs over several hotpots, including the Sahel and US Great Plains, have been found to intensify under global warming. However, compared to several other MCS hotpots, the investigation of long-term changes of MCSs is scarce over East Asia. Here, based on a high spatiotemporal resolution satellite precipitation product and a novel MCS tracking method, we find that MCSs have become more frequent and intense in the East Asian rainband and accounted for three quarters of the total rainfall increase during 2000-2021. It is further found that increases in atmospheric total column water vapor, which is mainly due to increased temperature caused by anthropogenic forcing, leads to more frequent large-scale water vapor-rich environments that are responsible for the intensification of MCSs. As water vapor increases with global warming, it is very likely that MCSs will continue to intensify in this region into the future. (This study has been published and selected as GRL Cover Paper, please see more details in: https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/grl.64259)

mesoscale convective systems, East Asian summer monsoon, global warming, extreme precipitation, novel tracking method