Abstract The upper‐level Hadley circulation is critical to the energy transport from tropical toward mid‐to‐high latitude regions. In this study, an index denoting the intensity of upper‐level Hadley circulation in Northern Hemisphere (Southern Hemisphere) is defined as the areal mean zonal mean meridional mass stream function in the upper‐level Hadley circulation, which is referred to as UP‐NH‐HCI (UP‐SH‐HCI). An increasing (decreasing) trend of UP‐NH‐HCI (UP‐SH‐HCI) is observed during 1979‐present using five reanalysis data sets, which denotes increased intensity of upper‐level Hadley circulation in Northern Hemisphere (Southern Hemisphere). Furthermore, Nine (13) CMIP6 models are selected to perform the detection and attribution analysis for the trends in UP‐NH‐HCI (UP‐SH‐HCI). Using the optimal fingerprinting method, the results indicate that the greenhouse gas forcing accounts for 57%–114% and 61%–89% of the observed changes in UP‐NH‐HCI and UP‐SH‐HCI, respectively, at an uncertainty range of 10%–90%.

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