Great Green Wall
A belt of restored land about 8,000 km long, from Senegal to Djibouti, on the southern edge of the Sahara, to halt land degradation and desertification. It was launched by the African Union in 2007.
What it is
At first it was conceived as a strip of trees about 15 km wide across the whole Sahel. Today it is rather a mosaic of projects: planting trees, but also restoring degraded land, pastures and fields. The 11 core countries are Senegal, Mauritania, Mali, Burkina Faso, Niger, Nigeria, Chad, Sudan, Eritrea, Ethiopia and Djibouti.
Key words
- Desertification
- Land degradation in arid and semi-arid areas, caused by climate and human activities (the definition of the UN Convention to Combat Desertification, UNCCD). It is not the desert “advancing”: it is land losing soil, water and plants.
- Isohyet
- A line joining places that receive the same amount of rain in a year, just as contour lines join places at the same height.
- Hectare
- 10,000 m², a square with 100 m sides. 100 hectares make 1 km²: the 100 million hectares of the target are 1 million km², roughly the area of Egypt.
Where it runs
In green, the belt receiving between 100 and 400 mm of rain a year, within the 11 countries and north of the 10th parallel: the Sahelo-Saharan zone where the project works, following the FAO criterion. It is not an official map but a representation: the project’s route is not published as open data, and the “wall” is a set of scattered projects inside this belt, a few hundred km wide.
- Between 100 and 400 mm of rain a year
- The 11 core countries
- 10th parallel north
The belt covers about 1,904,000 km². Rainfall: CHELSA 2.1 (Karger et al., WSL; CC0), 1981–2010 averages on cells of about 9 km; borders: Natural Earth. Area of the climatic zone (not of planted or restored land), computed by GeoScope.ch. The actual projects cover only a small part of this zone: up to 2020 about 40,000 km² in the project areas.
Targets and results
The targets set for 2030 and the assessment of the status report presented in September 2020.
Targets by 2030
- Land to restore
- 100 million hectares
- Carbon to sequester
- 250 million t
- Jobs
- 10 million
Land restored up to 2020
In the project areas: about 4 million hectares, 4% of the target
In all 11 countries, including outside the project areas: about 17.8 million hectares, 17.8% of the target
Of the roughly 17.8 million hectares, about 12 million are in Ethiopia.
Sources: UNCCD, The Great Green Wall Initiative; UNCCD, The Great Green Wall: Implementation Status and Way Ahead to 2030 (2020).
The 11 countries
How much of each country lies in the belt, how many people live there and how much CO₂ each person emits.
| Country | In the climatic zone (km²) | % of the country | Population | CO₂ per capita (t) |
|---|---|---|---|---|
| Senegal | 42,900 | 21.8 % | 19.4 million | 0.76 |
| Mauritania | 265,300 | 25.6 % | 5.5 million | 1.01 |
| Mali | 308,900 | 24.6 % | 25.9 million | 0.29 |
| Burkina Faso | 9,600 | 3.5 % | 24.6 million | 0.28 |
| Niger | 368,400 | 31.2 % | 28.8 million | 0.12 |
| Nigeria | 33,200 | 3.7 % | 242 million | 0.58 |
| Chad | 239,100 | 18.9 % | 21.6 million | 0.14 |
| Sudan | 461,800 | 24.9 % | 53.3 million | 0.35 |
| Eritrea | 70,400 | 57.3 % | 3.7 million | 0.21 |
| Ethiopia | 83,300 | 7.4 % | 139 million | 0.14 |
| Djibouti | 20,700 | 96.2 % | 1.2 million | 0.48 |
| Total | 1,904,000 | 565 million |
Climatic zone and % of the country: computed by GeoScope.ch from the map above, not planted land. Population: United Nations, World Population Prospects 2024 (2026). CO₂ from fossil fuels and industry: Global Carbon Budget 2025, via Our World in Data (2024); the world average is 4.73 t per person.
The indicators
In China: the “Three-North Shelterbelt”
Since 1978 China has been planting belts of trees along the deserts in the north, north-east and north-west of the country. Unlike the Sahel, it is the programme of a single state, planned until 2050 in three phases.
- Programme area
- 4.069 million km²
- Duration
- 1978–2050
- Provinces and regions
- 13
- Forest cover: at the start → target
- 5.05% → 14.95%
In green, the land receiving less than 600 mm of rain a year within the programme’s 13 provinces and regions: Heilongjiang, Jilin, Liaoning, Inner Mongolia, Beijing, Tianjin, Hebei, Shanxi, Shaanxi, Ningxia, Gansu, Qinghai and Xinjiang. As for the Sahel, it is not the official route but a representation: the programme mainly concerns arid and semi-arid land, and the area obtained this way is close to the declared one.
- Less than 600 mm of rain a year
- The 13 provinces and regions
The green zone covers about 4,076,000 km² (the 13 provinces and regions together about 5,315,000 km²; the programme declares 4.069 million). List of provinces and the 600 mm threshold (“for most of the area”): Zhang et al. (2016), Ecological Indicators; rainfall: CHELSA 2.1 (CC0), 1981–2010 averages; borders: Natural Earth. Area of the climatic zone (not of reforested land), computed by GeoScope.ch.
Source: United Nations, Partnerships for the SDGs, Three-North Shelterbelt Forest Program.
Sources: UNCCD; FAO (the zone between the 100 and 400 mm isohyets); CHELSA 2.1 (CC0); Natural Earth; United Nations (World Population Prospects 2024, Partnerships for the SDGs); Zhang et al. (2016), Ecological Indicators; Global Carbon Budget 2025 via Our World in Data (CC BY 4.0).