Africa builds Great Green Wall to fight desertification

Living on Earth

By Bobby Bascomb, Living on Earth

Senegal’s capitol city Dakar sticks out into the Atlantic Ocean on a peninsula. It’s at least a thousand miles to the Sahara desert yet the air today is so thick with sand that the tops of buildings disappear in a sandy haze. A fine layer of sand covers everything.

It’s the worst sand storm in a year and people here are worried that climate change will cause these events to be more common.  Seasons are shifting across the region. In Senegal the rainy season used to start in July or August but now it doesn’t start until September.

Decreased rain along with over grazing of land is causing an increase in deserts across the Sahel.  Roughly 40 percent of Africa is affected by desertification. The United Nations says two-third of Africa’s arable land could be lost by 2025 if the desertification trend continues.

Senegal is one of 11 countries in the Sahel region of Africa looking toward the same solution to the desertification problem: The Great Green Wall. The goal of the project is to plant a wall of trees, 4,300 miles long and nine miles wide, across the African continent, from Senegal to Djibouti. African leaders hope the trees will trap the sands of the Sahara and halt the advance of the desert.

Papa Sarr, technical director for the Great Green Wall in Senegal, is convinced that the project will help reduce the dust in Dakar.

In Widou, a village Sarr showcased, he shows off what he hopes will be a model for the Great Green Wall in Senegal. 

The paved roads of Dakar give way to red sand paths of the Shahel; a dry savanna transition zone between the equatorial jungles in the south and the Sahara to the north. Black and white goats meander in front of the truck and flat-topped acacia trees dot the sandy landscape. They are virtually the only vegetation in a region where the dry season can last up to 10 months.

Four hours northwest of Dakar, the village of Widou sits next to one section of Senegal’s Great Green Wall. The acacia trees here are just four years old, waist high and thorny. The trees are surround by a firewall and a metal fence to keep out tree-eating goats. All of the trees were chosen carefully. 

“When we design a parcel we look at the local trees and see what can best grow there, we try to copy nature. In total, we planted seven different species of acacia trees,” Sarr said.

Two million trees are planted in Senegal each year; all of them must be planted during the short rainy season. Laborers work long days to plant acacia saplings in the sand along with animal manure for fertilizer. Given that head start, agronomists are confident that the trees will survive well in the dry savannah.

Sarr points to a three-foot tall tree.

“This one is Acacia nilotica. It produces Arabic gum used in local medicine and a fruit that can be eaten by animals,” he explained.

For the project to succeed, it was crucial to plant trees that would also provide benefits for people living here. The government has ambitious plans for planting more trees but the Great Green Wall is also a development project, aimed at helping rural people.  

In the Senegalese Sahel the dominant ethnic group is the Peuhl.  Extremely tall and lean, they wear long flowing robes of emerald green and sapphire blue. They look like jewels against the rust colored sand and brown dry grass. The women have blue tattoos on their chins and wear heavy earrings that stretch their earlobes. Traditionally nomadic, the Peuhl are helping tend to the trees and planting gardens. One day a week, women in the area volunteer to help care for gardens full of carrots, cabbages, tomatoes, even watermelon. Guncier Yarati uses the side of her flip flop to mound the sandy soil around potato plants. 

“I like working here, “ Yarati said. “I like working with my friends, we laugh and play while we work but what’s really great is that we have more diverse vegetables. We eat the vegetables and can sell them in the market as well.”  

The closest market is about 30 miles away and before the gardens came along, it was a day’s trek on a horse drawn cart to get fresh vegetables. Now they are available just a few miles from home.

Most of the gardens are watered using drip irrigation. A hose with holes in it delivers just the right amount of water to each plant to minimize evaporation loss, but some plants, like carrots are watered by hand by people like Nime Sumaso.

“When people came from Dakar and showed us that they could plant vegetables in their center we saw that it was a way to help women in the community so we knew the Great Green Wall project was important for us,” Sumaso said.

For the Peuhl, work is divided largely based on gender. So, while women mostly see benefits of the project in their gardens, the men have a different perspective. A man’s primary responsibility is to care for the family’s large herds of goats and cows. 

In the early morning, white hump-backed cows with giant horns gather around water troughs. The Peuhl depend on their animals for subsistence, and livestock need a lot of water. In an area that gets as little as six inches of rain each year, water is life. Scientists say the trees of the Great Green Wall will improve rainfall and recharge the water table.

That’s welcome news for local herdsmen like Alfaca. 

“Planting trees is good for us,” he said. “Those trees can bring water and water is our future. Water can solve our problem. We are praying for this project to continue.”

Virtually everyone involved in the Great Green Wall agrees the end goal is to help rural communities. But opinions vary on how the project will do that.

African leaders envision the Great Green Wall as a literal wall of trees to keep back the desert. That’s what was proposed by the president of Nigeria, Olusegun Obasanjo, when he came up with the idea in 2005.

But scientists and development agencies see it more as a metaphorical wall, a mosaic of different projects to alleviate poverty and improve degraded lands. 

The Great Green Wall has received a total of $1.8 billion from the World Bank and another $108 million from the Global Environment Facility. Jean-Marc Sinnassamy, a program officer with the Global Environment Facility, says the Great Green Wall is less about reforestation and more about development. 

“We do not finance a tree planting initiative. It’s more related to agriculture, rural development, food security and sustainable land management than planting trees,” Sinnassamy said.  “Sustainable management of natural resources with the aim of reducing poverty is really our goal for this program.”

The 11 countries involved with the project are committed to making progress but there are many challenges: abject poverty, shifting seasons and political instability are top among them. The entire region is in the middle of a food crisis. The United Nations Food Program estimates that as many as 11 million people in the Sahel do not have enough to eat and Mali recently had a military coup.

Senegal is currently the furthest along with the Great Green Wall. They’ve planted roughly 50,000 acres of trees in addition to protecting existing trees. While it’s been successful so far in Senegal not everyone believes that it can work across the entire Sahel region. 

Gray Tappan, a geographer with the United States Geological Survey, said through the years, there have been many failed projects.

“There’s been a long history of one failure after another in external projects that come in and try to plant trees,” he said.

Tappan says there are many reasons they fail. Sometimes projects plant non-native species that aren’t adapted to the dry climate and die. Or local people don’t support the project and allow their goats to eat the trees. In the village of Widou those concerns don’t appear to be an issue but Tappan is skeptical that the Widou model can be emulated through 4,300 miles of varying ecosystems and communities.

He said a better model can be found in Niger. Historically, farmers there removed any trees or bushes that sprouted up in their fields. But following a devastating drought in the 1980s farmers decided to allow the natural vegetation to grow and planted food crops around it.

The result was a surplus of food and 12 million acres of trees, an area the size of Costa Rica. Tappan has spent 30 years working in the region and was shocked by the transformation. 

“In 2006 we did a big field trip across Niger and were just blown away by the vastness of this re-greening.”  Scientists like Tappan believe that type of natural regeneration is much more likely to succeed than planting trees. But political leaders in Senegal are committed to their vision. Djibo Leyti Ka, the Minister of the Environment, in charge of the Great Green Wall project for the entire country.

“We have a lot of desert from Senegal to Djibouti, 4,000 miles long. A wall of trees will stop the wind,” he said.

Ka dismisses critics who say it isn’t practical. 

They are crazy! The dust is coming. The sand is going to cover us all and we need to stop it. There are many many environmental projects in Senegal but this is the most important. This one will help men, women and children in the future,” he said.

Back at the Great Green Wall near Widou, Sarr stops to take in the work they’ve done so far. The waist high trees are just four years old but he expects big things from them. 

“In 10 to 15 years this will be a forest. The trees will be big and this region will be completely transformed. We are already seeing animals come back that haven’t been here for years. Mostly deer and many species of wild bird, even jackal,” he said.

It’s unclear if the newly elected president of Senegal, Macky Sall, will have as strong a commitment to the Great Green Wall as his predecessor Abdouley Wade. But for the people living here, tending their cows, watering the garden, and hoping the rains will come, the Great Green Wall holds great potential for positive change in Senegal and this region of Africa for generations to come.  

Sign up for our daily newsletter

Sign up for The Top of the World, delivered to your inbox every weekday morning.