Exploring the impact of the Great Green Wall on Atlantic Tropical Cyclone activity

Abstract

The Great Green Wall (GGW) initiative aims to restore 100 million hectares of degraded land over the Sahel. However, its potential impacts on the far-afield climate have hitherto not been evaluated. Here, we use a high-resolution regional climate model to evaluate the potential impacts on Atlantic tropical cyclone (ATC) activity in four different GGW scenarios under two emission pathways. The results reveal a shift in ATC genesis from the subtropical and western Atlantic to the eastern Main Development Region under medium to extreme vegetation density scenarios, compared to cases without the GGW. An increase in genesis is also observed off the coasts of eastern Florida and the Carolinas under the high-concentration pathway. However, no significant change in basin-wide TC frequency is found. Instead, the main impact of GGW appears to be a redistribution of tropical cyclogenesis within the basin. Our analysis highlights the primary role of African Easterly Waves in driving changes in TC genesis across the eastern MDR, while large-scale environmental factors – though secondary overall - primarily influence changes off the southeastern U.S. coast. No GGW-induced changes are found in the ATC intensity, translation speed or other TC metrics across the entire basin.