Vertical and Regional Dependence of the Hadley Cell's Upwelling Response to Increased CO2

In recent years, attention has been given to the Intertropical Convergence Zone's (ITCZ) response to a changing climate. Several studies predict a narrowing and enhancement of the ITCZ, but the lack of robustness across coupled climate models has obfuscated that result. Here, we present a comprehensive view of the Hadley Cell's upwelling response to increased CO2. Analysis of CMIP6 models shows a consistent vertical dependence such that the upwelling narrows and strengthens in the upper troposphere while widening and weakening in the lower troposphere. Further, we consider the upwelling's response as a function of longitude to illuminate the physical mechanisms responsible for the vertical pattern.