In 1986 at the Silva Conference for the Protection of the Trees and Forests in Paris, Burkinabé president Thomas Sankara delivered a speech remarkable for its foresight into the most pressing issues for Sahelians and global citizens that remain true even today. In his speech, “Imperialism is the Arsonist of Our Forests,” he summarized his administration’s efforts to regrow Burkina Faso forests and replenish the country’s soils after the ecological devastation wrought upon his people’s land by colonization and modern-day ignorance. Keenly aware of the locale and nationality of the attendees of the conference, he pointed out that his country bore the burdens of the Global North’s indifference to climate change, which exacerbated many problems for Burkina Faso.
Sankara proposed to the conference of first-world leaders (and previous colonizers of Upper Volta) that they spend 1% as much on environmental efforts as they do on space travel as a form of reparations: “[…] Burkina has proposed and continues to propose that at least 1% of the colossal sums of money sacrificed to the search for cohabitation with other stars and planets be used, by way of compensation, to finance projects to save trees and lives. We have not abandoned hope that a dialogue with the Martians might lead to the reconquest of Eden. But in the meantime, earthlings that we are, we also have the right to reject a choice limited simply to the alternatives of hell or purgatory” (Sankara 1988, 259). As a rejection of purgatory and hell, Sankara opted for eden, and his presidency is often associated with the legacy of planting ten million trees.
Thomas Sankara was assassinated the following year. However, his regreening efforts were revitalized in 2005 by Nigerian president Olusegun Obasanjo at the 7th Summit of CEN-SAD, a partnership organization for Sahelian countries wishing to collaborate on international agreements. I was unable to find documentation of President Obsanjo’s particular contribution; however, he is most commonly credited with the revival of Sankara’s dream to regreen the Sahel. This dream has taken the form of a large scale collective tree-planting effort known as the Great Green Wall (GGW). Communities involved aim to regreen arid lands and secure their natural resources. In doing so they continue a legacy of adaptation and resilience which has ensured their survival for generations.
The GGW is an international, yet locally adaptive, response to desertification with a chance of influencing global aerosol levels: a living example of the new tone for the environmental movement “think globally, act locally.” The Great Green Wall received approval from the African Union (AU) in December 2006. Following this, funding poured in from organizations and member states gained co-financing and partnerships with large institutions using the World Bank as an implementing agency. Just this year, on January 11, 2021, pledges totaling 14.3 billion euros were made at the One Planet Summit to fund the GGW. In June 2010, eleven African countries in the Sahel signed a convention in Chad to further develop the project. The same year, the GGW gained recognition from the AU as a Pan African Agency, officially known as the Pan-African Agency of the Great Green Wall. The Pan-African Agency of the Great Green Wall provides a platform for member states to consult one another. The wall is governed by the Heads of State and Government of the Sahelo-Saharan countries, passing through Djibouti, Eritrea, Ethiopia, Sudan, Chad, Niger, Nigeria, Mali, Burkina Faso, Mauritania, and Senegal (IPPC 2019). Twenty-one northern African countries now participate in the GGW. The project has evolved to include an array of stakeholders, including national governments across the world, international organizations, private corporations, and civil society (Pan-African Agency of the Great Green Wall 2018).
The GGW has been underway for over a decade. The project is so large that it requires tens of thousands of Sahelian community members to participate in the planting efforts. Community members cultivate planted sections along a 7,775-kilometer stretch from Senegal to Eritrea on the Red Sea coast, approximately 15 kilometers wide. The Great Green Wall was so named because many envisioned it as a wall to stop the southern growth of the Sahara, though current research shows that the Sahara is not growing southward as was previously believed and published in IPCC reports (Pierson 2019). The GGW is more of a mosaic of parcels maintained at the discretion of individual countries and communities.
The sheer size of the project cannot be overstated. The GGW is a massive overhaul of an entire ecological region of the world, and therefore assessing costs and benefits is messy. From the perspective of an outside observer, certain solutions may seem ideal; however, these solutions often lack consideration of many vital elements contributing to the project’s success. What is clear is that community stakeholder buy-in is indispensable; sometimes this means listening to communities’ wants and needs above avant-garde research coming from outside observers.
Sahelian communities have adapted to the extremes of the Sahel for thousands of years. Ecologically, the Sahel is transitional land at the base of the Sahara, composed of arid and semi-arid rangeland ecosystems with low-growing grasses, tall herbaceous perennials, thorny shrubs, and trees. The climate is tropical and semi-arid, with constant intense heat in the interior region. Countries can expect to see somewhere between 200 mm and 700 mm of rain annually based on proximity to the West African monsoons. The Sahel is often described as one of the most vulnerable regions to climate change in the world. As temperatures rise globally, they are rising faster in Africa affecting the most vulnerable regions the most severely (WMO, 2020). Furthermore, from 1951 to 2010, precipitation decreased severely throughout the Sahel. Some recovery during the last 20 years could be within the range of natural climatic variability and human actions (IPCC, 2014).
Communities of this region are particularly vulnerable to climate change due to heavy reliance on natural resources, “as 70-92% have agriculture and/or livestock production as their main livelihood activity” (Goffner, Sinare, and Gordon 2019). Sahelians practice agro-pastoralism, a practice balancing livestock and crop cultivation to take advantage of the Sahel’s dry and wet periods. This practice has survived droughts, the slave trade, and colonization. Now, after thousands of years of adapting to the Sahel, Sahelians are attempting to adapt the Sahel to them. This includes ecological knowledge about the building of rain water reservoirs, seed fertilization for fast-tracking seed growth, knowledge about the types of crops that are capable of withstanding the high temperatures of the Sahelian climate, as well as reintroducing agroforestry which utilizes the microclimates created by species variation within a given parcel generating healthier plants and doing it all on a massive scale.
As an example of how the GGW functions on a local scale and how it integrates traditional ecological knowledge, botanical and forestry experts out of the Royal Botanic Gardens, Kew, UK, and FAO’s Forestry Department have been working with communities from Burkina Faso, Niger, and Mali to develop and implement agreeable tree-planting schemas. According to one study led by Moctar Sacande, Research Leader in the Natural Capital Department of the RBG, Kew, forest seed physiologist, and dryland restoration expert leading the GGW restoration project in West Africa, planting a combination of slow-growing native woody plants and fast-growing edible herbaceous and fodder species has been successful (Sacande 2015). Community knowledge is integrated into the schema through data derived from village workshops and questionnaires. The species selected represent the communities’ interest in cultivation for medicinal use, food for livestock and community members, and for fuel. Traditional knowledge informs the process of cultivation, planting, and maintaining the GGW. Such processes, such as transplantation of seedlings, can actually strengthen the crops’ root systems and create efficiencies during later parts of cultivation (Carney 2009).
Other examples of traditional ecological knowledge at work include methods of maximizing the retention of precipitation, thus maintaining moist soils which allow planted seeds and preexisting seed to grow. Farmers in Burkina Faso build traditional Zais: pits dug into the ground in formations that enhance rainwater retention. These techniques have been credited with the rising water tables in places like Burkina Faso, though climate variability and increased rainfall from the 1980s may also be contributing factors. These methods of increasing water retention in soils have aided in the resurgence of traditional agroforestry which has been on the rise since the 1980s. Farmers steward already existing tree seeds that sprout alongside crops of millet, maize, sorghum, and other crops (Carey 2020). Farmers have found that a symbiotic relationship exists between tree growth and crops, knowledge which was oppressed during years of colonization when monoculture was predominant among European farmers. Much knowledge is passed down by women who play a major role in the GGW throughout many of the hosting countries. This follows traditions of women’s leading roles in crop cultivation pre-European colonization (Carney 2009). Women also often run the community gardens established alongside parcels of the GGW.
There is much more to be said about modern and traditional techniques in agroforestry and agro-pastoralism in the Sahel. Overall, Sahelian community members seek to change regional climates and create new opportunities and avenues for resources, making their work beneficial to their present and future. Community members are offered various incentives such as food security, water, access to resources, and payment to participate. The ecological success of the GGW means greater biomass production throughout the Sahel, which can mitigate regional climate changes. Communities maintaining parcels of the GGW also benefit from community gardens and some food sources from the parcels themselves, which serve as either immediate food sources or additional revenue due to the crop’s economic potential. The GGW’s success in attracting funding nationally and worldwide means that Sahelians benefit from the money and resources funneling into the region from international sources. Their work transforms their immediate environment, climate, and, ultimately, their livelihoods.
Trees’ ability to sequester atmospheric carbon makes the GGW a feat of geo-engineering: the collective mass of trees acts as a significant carbon sink. However, it’s not just trees contributing to a decrease in greenhouse gasses. The project mitigates climate in several ways. For example, soil also sequesters carbon. Planting forested areas results in an accumulation of detritus and the build-up of soil rich in biological activity. Also, as land is reclaimed for the GGW, land albedo decreases. Lastly, the Sahara is the most significant contributor of mineral dust, an atmospheric aerosol that makes up half of the total aerosol load in the atmosphere. Reclaiming desert lands has the potential to affect a globally relevant decrease in aerosol load (Pausata et al. 2020).
The sheer spatial scale of the GGW allows it to be influential on both local climates and global scales, but it is also the reason it requires so much community engagement, and it’s only growing. The UN outlines that, by 2030, the initiative will enter a new phase. A UN report states, “[the GGW initiative aims to] restore 50 million hectares of land; sequester 250 million tons of carbon; support 300 million people in communities across the Sahel; and provide access for 10 million smallholder farmers to climate-resilient agricultural technologies” (UN Environment 2019). In addition, this project has spurred the Action Against Desertification initiative by the FAO, EU, and the ACP—organizations with the aim to restore arid and degraded lands in Africa, the Caribbean, and the Pacific (FAO 2020).
From its history, we can see the Great Green Wall as a response to local economic necessity, an act of land reclamation, and Sahelian unification: “The present growing consensus among partner stakeholders is that GGW is not about afforestation and reforestation only, but about food and livelihoods, job creation, improved grazing facilities, fisheries and sustainable farming” (Gadzama 2017). Monique Barbut and Tumusiime Rhoda Peace write in a UNCCD report titled “A Great Green Wall: Hope for the Sahara and the Sahel” that the initiative is an intervention of sustainable land management, serving as a beacon of hope for the African people and other areas of the world also fighting for land degradation neutrality (UNCCD 2016). This sort of stakeholder buy-in may be useful to consider in future environmental initiatives. Peace further elucidates that for local Sahelians and country leaders, the GGW is less about a geo-engineering solution to climate change and more about “[…] improving the living conditions of local populations on the long term to live on their land thanks to their labor, by increasing their incomes and ensuring their food security” (Peace 2016). While the project has resulted in global success, that success relies almost entirely on Sahelians continued adaptability to their environment.
 This could be due to the media’s focus on the Summit’s broader movement to transform the Sahel into a place of economic growth, free movement, free trade, and shared rights among citizens of member states. It should be noted that the Great Green Wall certainly falls in line with Obasanjo’s presidential commitment to agricultural reform at the time (Ford, 2005).
 Wall-like effects from the GGW may perhaps combat soil erosion due to wind (O’Connor and Ford, 2014). Other net climate positives may be seen from the effort as well. Recently some researchers have built on the Great Green Wall’s success, stating that its overall ecological and humanitarian benefits could increase by placing greater focus on shrubs than trees (O’Connor and Ford, 2014). Furthermore, additional research indicates that a focus on local hydrological regimes through forest water interaction frameworks may see the best results in increasing net rainfall (Ellison and Speranza, 2020).
 Significant successes were announced at the United Nations Climate Change Conference held in Paris, France, in 2015. The United Nations Convention to Combat Desertification web page lists the following achievements regarding the GGW initiative:
- Ethiopia: 15 million hectares of degraded land restored, land tenure security improved;
- Senegal: 11.4 million trees planted, 25,000 hectares of degraded land restored;
- Nigeria: 5 million hectares of degraded land restored and 20,000 jobs created
- Sudan: 2,000 hectares of land restored;
- Burkina Faso, Mali, Niger: about 120 communities involved, a green belt of 2,500 hectares of formerly degraded and drylands, more than two million seeds and seedlings planted from fifty native species of trees.
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*Cover image: A partial view of the Sahara Desert on the African continent from space. To the south of this region, a green band of forest reaches across the continent. Image via Wikimedia Commons.
[*Cover image description: a section of the northern part of Africa as seen from space, including the Sahara Desert in shades of yellow and tan. At the bottom, a green band.]