The Great Green Wall Strengthens the West African Monsoon

The Great Green Wall (GGW) initiative aims to restore 100 million hectares of degraded land across 22 African countries by 2030, as a flagship initiative under the United Nations Convention to Combat Desertification. Despite its ecological significance, the climatic impacts of the GGW, particularly on the West African Monsoon (WAM) system, remain insufficiently understood within a fully coupled Earth system framework. Here, we employ a coupled model with prescribed vegetation restoration over the northern Sahel to assess the GGW's impact on the WAM. We find that the Sahelian rainfall increases by 22%, accompanied by strengthened monsoon westerlies and the tropical easterly jet, and a northward shift of the African easterly jet. Both vegetation‐rainfall feedback and atmosphere‐ocean interaction mechanisms are important for the changes in WAM. Vegetation restoration reduces surface albedo, increasing available surface energy for latent heat flux and enhancing local moisture recycling through evapotranspiration. The resulting convective heating induces a Gill‐type atmospheric response, characterized by cyclonic circulation anomalies over the tropical North and South Atlantic, weakening (strengthening) surface wind speeds and warming (cooling) sea surface temperatures (SSTs) in the tropical North (South) Atlantic. The enhanced meridional SST gradient further strengthens the WAM circulation, increasing moisture transport from ocean to land and dynamically amplifying the Sahelian rainfall. Moreover, the enhanced moisture transport maintains a more humid atmosphere over the Sahel, thermodynamically favoring convection development. These findings reveal a clear physical linkage between large‐scale land restoration and monsoon dynamics, highlighting the GGW's potential to enhance regional hydroclimate resilience and inform long‐term climate adaptation strategies.