In the Sahel, the idea of a “green wall” should make it possible to slow down the advance of the desert. Sougueh Cheik, doctor in environmental sciences at IRD, discusses this project.
An area particularly vulnerable to climate change, sub-Saharan Africa is today facing many challenges, often interconnected: Food Safety and water, reduction of land degradation, sustainable management of natural resources and ecosystems, and reduction of extreme poverty.
These challenges are likely to be exacerbated by the steadily increasing population in the region, which is expected to grow by 1,4 billion by 2030 and 2,1 billion by 2050.
At the heart of sub-Saharan Africa extends this vast arid and semi-arid tropical region called the Sahel, which crosses all the countries bordering the south of the Sahara from Senegal to Djibouti. In this area, two thirds of the population live on animal and plant production.
From an environmental standpoint, rising temperatures and changing rainfall patterns tend to exacerbate environmental hazards, accelerate desertification, compromise food security and increase degradation of biodiversity and ecosystem services.
For decades, recurrent droughts have therefore become a priority emergency in the region. In Africa, desertification affects about 45% of the area, from wetlands to arid and semi-arid areas, and affects around 485 million people.
The threat of desertification in the Sahel
In the Sahel, the average annual rainfall varies from 200 mm in the north to 600 mm in the south. The rainy season is intense and lasts about four months, with prolonged dry spells. The region is heavily dependent on agriculture and pastoralism - main economic activities that employ 70% of its working population.
Or nearly 95% of agriculture in Africa is rainfed, high climate variability and low rainfall that characterizes the region make her particularly vulnerable.
To this variability are added anthropogenic factors such as urbanization, overexploitation of soils, bush fires and overgrazing, with high levels of poverty, rapid population growth and conflicts in many regions of the Sahel.
These multidimensional and interdependent challenges come up against the weak adaptive capacity of socio-economic systems. In the Sahel, an estimated 29,2 million people are food insecure, 9,4 million of whom are at risk of extreme food deficits.
For all these reasons, adaptation appears to be a priority for climate policy in Africa and various institutions to combat desertification and drought have emerged.
Significant progress has therefore been made in this area over the past decade, in particular the establishment of adaptation funds through the United Nations Framework Convention on climate change, the development of national and regional adaptation action programs and the integration of this dimension into development projects. The Great Green Wall is an emblematic example.
Green barrier against the advance of the desert
The idea of a living barrier to resist the perceived advance of the Sahara Desert is not new. The concept of green dam was launched in Algeria in the 1960s by the former president Houari Boumediene.
It was during the seventh summit of heads of state and government of the community of states of the Saharo-Sahelian zone of the Circum-Sahara in 2005 in Ouagadougou (Burkina Faso), that the idea of the Great Green Wall was proposed. Its overall objective is to strengthen the resilience of the populations and natural systems in the area.
Launched in 2007 under the aegis ofAfrican Union and the Pan-African Great Green Wall Agency, the initiative aims to stop desertification and land degradation in the Sahelian zone and improve the livelihoods of smallholder farmers and pastoralists in the region.
The first step consists of planting a forest strip of 7000 km long and 15 km wide composed of a mixture of native tree species that would cross the African continent from Senegal to Djibouti, along the southern edge of the Sahara Desert (Senegal, Mauritania, Mali, Burkina Faso, Niger, Nigeria, Chad, Sudan, Ethiopia, Eritrea, Djibouti).
Restore 100 million ha of degraded land
Originally designed as a strip of vegetation, along the Dakar-Djibouti axis, it now extends to more than 20 countries in Africa, including North Africa (northern Sahara) and Africa. Southern (Southern African Development Community country).
The strategy aims to harmonize interventions with other ambitious approaches in courses in the region, such as the African Forest Landscape Restoration Initiative AFR 100 or Bonn challenge which in 2011 intended to restore 150 million hectares of degraded and deforested land before 2020, and 350 million hectares before 2030.
In addition, the Pan-African vision has shifted from a simple reforestation project to a series of multisectoral interventions at the landscape scale, aimed at improving social and ecological well-being in the region. Each member country has thus defined a set of native tree species for reforestation based on on their adaptability to the environment and their usefulness for local populations.
The Great Green Wall initiative has brought together African countries and international partners in a project that aims to restore 100 million hectares of degraded land, sequester 250 million tons of carbon and create ten million jobs by 2030.
Of the 100 million hectares planned for 2030, 4 million hectares have been restored to date. Although the Great Wall has been proposed as a climate change adaptation strategy, it could also have mitigation benefits by sequestering carbon through large-scale plantations.
Include communities in the process
In view of the complexity of the challenges, the success of such an initiative is highly dependent on a pacification of the region and a better ownership of the project by the local communities through a more inclusive approach.
In addition, the identification of areas suitable for afforestation and / or agricultural practices remains a challenge. According to a recent study, 43,5% of the area of the Sahel and 25,6% of that of the area proposed for the Great Green Wall are not suitable to a sustainable plantation. It will therefore be necessary to combine the planting of well-chosen tree species with other forms of land use (crops, grazing, gathering, etc.), which requires a land and legal framework.
Finally, it would be important to better reconcile scientific knowledge and traditional knowledge of local populations to find the best solutions through participatory and innovative approaches to restoration of degraded lands.
Sougueh Sheik, Doctor of environmental sciences, Research Institute for Development (IRD)
This article is republished from The Conversation under Creative Commons license. Read theoriginal article.