[LUM#21] Anatomy of a Fall
Has the Great Green Wall of Africa project, launched in 2008, already failed? Many people think so, given its apparent inertia. Political instability in many of the countries concerned and the blocking of promised funding are now hindering soil rehabilitation through the planting of forests that may never have existed except on paper.
Some would say that the idea has run its course, but he prefers to warn: "Abandoning a project that has received so much media attention would be a disappointment and an admission of extraordinary weakness." Robin Duponnois, research director atIRD, was also the project leader for the Great Green Wall (GGW) project in Dakar. He states bluntly that the GMV's objectives "are far from being achieved and will not be any closer to being achieved in 2050. However, the analysis on which the project is based is sound. We are not introducing anything new, we are not destroying anything, we are listening to the local populations. The only risk is that there will be no effects."
In 2008, 11 countries participated in the launch of the operation: Senegal, Mauritania, Mali, Burkina Faso, Niger, Nigeria, Chad, Sudan, Eritrea, Ethiopia, and Djibouti. The goal: to plant trees on a 15-km-wide strip of land along a 7,000-km belt stretching from Dakar to Djibouti, to prevent the desertification of land degraded by human activities (see: Research sol majeur, 10/11/2021, LUM Magazine 15). "Hence the somewhat misleading term 'wall against the desert', but the Sahara is not advancing, it is just recovering surface area," the researcher subtly clarifies .
Under the trees
The idea is not new. The 1970s saw the emergence of the "Green Dam" in southern Algeria (Algeria relaunches its Green Dam megaproject, 8/11/2023, Jeune Afrique), the "Great Wall" in China (see box), and the "green belts" of Ouagadougou and Cairo. Almost all of them failed, but these early failures taught a valuable lesson: "All these projects were designed with exotic tree species, most often in single-species plantations. In the end, these forests did not regenerate or were ravaged by pathogens," notes the forest biology specialist.
The stakeholders involved in the Great Green Wall project have therefore decided to plant only local trees. Two species are favored: Acacia senegal, which produces gum arabic, highly prized in pharmaceuticals, and Balanites, whose bark and thorns are also valuable. "The GGB is primarily presented as an environmental rehabilitation project," notes Robin Duponnois. "But beneath the trees lie social and economic issues such as the combination of crop farming and livestock breeding, which are still antagonistic in these regions, entrepreneurship, the promotion of local produce, etc. " (La Grande Muraille Verte. Capitalisation des recherches et valorisation des savoirs locaux, A. Dia, R. Duponnois, 2012, IRD Editions).
Locomotive without a car
In Senegal, for example, multi-purpose gardens have been co-developed in many villages. "Women have been trained so that they can sell their produce and no longer have to travel 30 kilometers every week to get to the market." The gardens found their audience before they too were affected by the decline of the GMV project. "In the village of Tessekere, the funds needed to repair a pipe never arrived, so the garden was gradually abandoned. There is no continuity in project development, even though we have the technology and processes in place, " he notes with a hint of bitterness .
Robin Duponnois immediately tempers this sentiment: "In northern Senegal, you have acacia plantations that are doing very well. There are still nurseries and gum arabic production is picking up. Senegal remains the driving force behind the project. " (read: The Great Wall is slowly making its way in Senegal, 04/15/2016, Le Monde). A driving force, certainly, but one without a train, since the GMV seems to be stalled in most other countries and the Great Green Wall accelerator, launched with great fanfare in 2021, is still waiting to get off the ground.
Trees of Peace
How can we explain that Senegal, with a GNP roughly equivalent to that of its other partners, is one of the few countries continuing the effort? "Because it currently enjoys a political stability that many others do not have," replies the scientist. Burkina Faso, Mali, Nigeria, Eritrea... are in unstable situations, and the Great Green Wall is no longer a priority for these states. And while international partners have promised colossal sums of money, you don't put money into a country at war. It remains to be seen whether the wall will recover (see Accelerating the mobilization of African and international scientific expertise to boost interdisciplinary research for the success of the Sahelian Great Green Wall by 2030, 10/2022 , Land).
Green dragon versus yellow dragon
It is the largest man-made forest in the world, covering more than 500,000 square kilometers (2009) of poplars, pines, and willows planted since the late 1970s in China to combat the Yellow Dragon. These storms from the Gobi Desert, which, in the absence of obstacles, have for years dumped hundreds of thousands of tons of sand as far as Beijing, located 350 km further south. " The idea was to reforest the area to stabilize the dunes and prevent these sandstorms, " explains Robin Duponnois. They also tested cyanobacteria to create crusts on the ground and set up large nurseries using highly sophisticated in vitro cultivation techniques. They built a whole system of canals to deliver water drop by drop...".
Fifty years later, despite the human and social cost of the numerous expropriations and population displacements it required, China's Great Green Wall is considered a success. Vegetable-growing areas have been established, monospecific forests have given way to a diversification of species, and ecotourism has developed. "There's even a chairlift in the middle of the dunes, " jokes the researcher. But China is not stopping there. In 2018, it mobilized 60,000 soldiers (Le Figaro, February 8, 2018) to achieve its goals by 2050: planting 35 million hectares of forest 550 kilometers wide and 4,500 kilometers long. Not enough to green its stone twin, which is 20,000 kilometers long.
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