Africa's Great Green Wall project began as an ambitious plan to build a 15-kilometer-wide band of trees across the north of Africa. The African Union launched the project in 2007 with plans for the trees to extend for 6,000 kilometers through 11 countries in the Sahel, restoring 100 million hectares of land from Senegal to Djibouti and Ethiopia. Its main aim was to prevent the Sahara Desert from advancing. But the Great Green Wall's also been billed as a solution to climate change, poverty, and even extremism.

Senegal has been one of the most active countries implementing the Great Green Wall initiative, despite being among the smallest. It has targeted 817,500 hectares of land for restoration. Environmental researchers Annah Lake Zhu and Amadou Ndiaye were part of a team who looked at satellite images of some of Senegal's section of the wall and found that only one out of 36 planted areas analyzed was more green than it would have been naturally. The project is not an actual wall of trees but rather a mosaic of rehabilitated land. But increased greenery should still be visible from satellite imagery. They also found that financial pledges were often left unmet, money for the wall didn't make it to ground level and new trees had low survival rates.