The wall envisioned by 11 African countries on the southern border of the Sahara, and their international partners, is aimed at limiting the desertification of the Sahel zone

Imagine a green wall – 15km wide, and up to 8,000km long – a living green wall of trees and bushes, full of birds and other animals. Imagine it just south of the Sahara, from Djibouti in the Horn of Africa in the east, all the way across the continent to Dakar, Senegal, in the west.

The building of this pan-African Great Green Wall (GGW) was approved by an international summit this week in the former German capital Bonn, a side event of the joint conference of the committees on science and technology and for the review of the implementation of the UN Convention to Combat Desertification (UNCCD).

The GGW, as conceived by the 11 countries located along the southern border of the Sahara, and their international partners, is aimed at limiting the desertification of the Sahel zone. It will also be a catalyst for a multifaceted international economic and environmental programme.

The Sahel zone is the transition between the Sahara in the north and the African savannas in the south, and includes parts of Burkina Faso, Chad, Djibouti, Eritrea, Ethiopia, Mali, Mauritania, Niger, Nigeria, Senegal and Sudan.

The GGW initiative initially involved the planting of a 15km-wide forest belt across the continent, with a band of vegetation as continuous as possible, but rerouted if necessary to skirt around obstacles such as streams, rocky areas and mountains – or to link inhabited areas.

During the meeting in Bonn, the Global Environment Facility (GEF) confirmed its promise to allocate up to $115m to support the construction of the green wall. Other international development institutions also made investment pledges to support building the wall, of up to $3bn.

The GEF – formed by 182 member governments, numerous international institutions, non-governmental organisations and the private sector – provides grants to developing countries and those with economies in transition for projects related to biodiversity, climate change, international waters, land degradation and the like.

"The Green Wall should be seen as a metaphor for the co-ordination of a variety of international projects, for economic development, environmental protection, against desertification, and to support political stability in the heart of Africa," said Boubacar Cissé, African co-ordinator for the UN secretariat against desertification.

The GGW was first proposed in the 1980s by Thomas Sankara, then head of state in Burkina Faso, as a means to stop the growing of the Sahara. The idea was voiced again about 20 years later by the then Nigerian president, Olusegun Obasanjo, who presented it to the African Union (AU) in 2005.

Since then, the project has gained international support outside Africa.

The GGW would have numerous advantages. Other than stopping desertification and erosion, the wall would protect water sources, such as Lake Chad, which has been drying up for decades, and restore or create habitats for biodiversity.

In addition, the wall would provide energy resources; fruit, vegetables and other foodstuffs; support local economic development; and even political stability in the whole region, said Daniel André, of the UNCCD.

"The construction of the Great Green Wall across Africa should be the motor for international co-operation, both at the national and at the communal level, with the objective of fighting poverty," André, who is from Senegal, told IPS.

"The objective of the project is more than stopping desertification," he added. "It goes straight to the heart of the fight against poverty: it must provide people across the continent with an economic perspective to stop the youth migrating from the region, it must provide the region with a cushion against climate change, and by so doing also help to restore political stability."

André said that political stability is most important now, given the present political turmoil in the Arab world – an immediate neighbour to all 11 countries involved in the construction of the GGW.

Bernd Wirtzfeld, of the German ministry for economic co-operation and development, said that international donors were ready to support the project.

"In its current design, GGW is much more than its name or its trajectory suggest," said Richard Escadafal, chair of the French Scientific Committee on Desertification. "Its aim is to ensure the planting and integrated development of economically interesting drought-tolerant plant species, water retention ponds, agricultural production systems and other income-generating activities, as well as basic social infrastructures," Escadafal said.

Escadafal also pointed out that beyond the technical problems associated with the initiative, "its success considerably depends on the social setting in which these plant propagation and tree planting projects are conducted".

"Projects in which reforestation was put in practice without the participation of local inhabitants were almost always limited and non-sustainable," Escadafal warned. "When farmers' rights and what they could hope to get back from their labour remain uncertain, technical efforts to select the best species, to enable them to develop properly in modern nurseries using advanced planting techniques, could generate some good results, but only in the short term."