Sustainability: Benefits of the African Great Green Wall assessed

Investing in land restoration as part of the African Great Green Wall programme yields, on average, US$1.2 in return for every dollar invested, according to a cost–benefit analysis of recent projects published in Nature Sustainability. These findings reveal that restoring degraded land in this context might not just be good for the environment, but also make economic sense.

Commencing in 2007, the African Great Green Wall is an ambitious programme that aims to restore 100 million hectares of degraded ecosystems across 11 countries in the Sahel region in sub-Saharan Africa. The programme includes growing trees and other plants, as well as further initiatives across countries south of the Sahara Desert — a region where land degradation threatens livelihoods and food security.

Alisher Mirzabaev and colleagues evaluate the costs and benefits of land restoration activities that constitute the African Great Green Wall programme. Under a range of assumptions and scenarios, the authors find that projects take ten years at most to break even, although there are differences across countries and biomes — large regions characterized by their climate and the communities of organisms that live there. The authors find that every US dollar invested in these projects under the base scenario — one assuming flexible and maintained restoration of biomes and a preference for achieving project returns quickly — yields, on average, US$1.2. To fund all of the proposed land restoration activities, US$44 billion is needed under the base scenario (US$18–70 billion across scenarios). Mirzabaev and co-authors also estimate that violent conflicts notably reduce access to proposed restoration sites — with the area decreasing from 27.9 million hectares to 14.1 million hectares.

The authors conclude that this study provides guidance on activities and locations where land restoration may be more cost-effective and ecologically sustainable. This knowledge could help with the targeting of future projects, they conclude.