When you think of the Sahara, you probably imagine a vast arid landscape of sand dunes, and… not much else. But 8,000 years ago, the Sahara was a completely different place. Animals like hippos and giraffes roamed what was then a lush green land of lakes and rivers, covered with trees and grasses. Humans also migrated into the region to take advantage of its fertile soils.
This span of time was known as the African humid period, or the Green Sahara, when the Saharan climate was about 10 times wetter than it is today. It began at the end of the last ice age, around 14,000 years ago, and came to a grinding halt about 5,000 years ago, when the Sahara suddenly dried up, and its people left for greener pastures further south. So, how did these drastic changes come about? Well, they were partly due to changes in the Earth’s orbit that cause the climate in northern Africa to switch between arid and humid roughly every 20,000 years.
But something strange happened the last time the Sahara dried up. That time, it happened much more quickly than it did in the past. Now the question is: could humans have played a part in pushing it past a tipping point? When humans migrated into the region during the African humid period, they brought with them livestock like sheep, goats and cattle. According to archeologist David Wright, these animals slowly gobbled up the grasses, which exposed the bare soil underneath. Soil and sand are a lighter color than grass, so they tend to reflect more sunlight. This heats up the atmosphere, but crucially, it also weakens the African monsoon. So, the climate becomes both hotter and drier, causing drought. That causes more vegetation to die out, which worsens the drought. Wright believes this feedback loop was what caused the Sahara to turn into a desert so quickly – and it all started with humans and their livestock. Today, the Sahara is growing rapidly, at a rate of around 10% over the last 100 years, making it a prime example of what’s known as desertification, a type of land degradation that affects drylands and causes their soils to become less productive over time.
Located just south of the Sahara is this semi-arid region called the Sahel. It consists mainly of grasslands and savanna and serves as a crucial buffer between the desert in the north and the Sudanian savanna in the south. The Sahel is currently home to around 135 million people. But that population is rapidly growing and could reach 330 million by 2050. That’s around the same population as the United States. Most Sahelians used to be nomadic herders who migrated seasonally depending on where grass and water were available, but many of them have now settled down. Unfortunately for them, the Sahel is slowly turning into a desert – in other words, it’s being swallowed up by the Sahara. Between the 1960s and the 1980s, the Sahel went through one of the worst droughts of the 20th century, and around 100,000 people lost their lives due to famine. To this day, the Sahel is still getting far less rainfall than it did during the first half of the 20th century. Meanwhile, human-induced climate change is making droughts more common and more severe.
Land and water resources are becoming increasingly stretched, which is contributing to armed conflict across the Sahel. In the north, in countries like Burkina Faso, Mali, Niger and Chad, almost 3 million people have been displaced by violence between nomadic tribes, local militias, national and international armed forces, organized crime networks, and jihadist groups, all fighting for control over the region. Meanwhile in the south, the expansion of agriculture is creating conflicts between nomadic herders and farmers. When herders migrate south to find grass and water for their animals, they’re now finding these lands fenced off and turned into fields, as farmers have been encouraged to settle, expand their agriculture, and obtain land rights. In Nigeria, over 10,000 people have been killed in clashes between farmers and herders over the last decade. As a result of these conflicts, Sahelian herders are being squeezed by violence in both the north and the south, while at the same time, desertification is making it even harder for them to maintain their livelihoods.
According to the United Nations, around 29 million people across the Sahel are now in need of humanitarian aid due to hunger and insecurity. So, how could we stop the Sahel from drying up any further? First things first – we need to address the underlying causes. That means cutting greenhouse gas emissions to combat climate change. It means promoting sustainable land use. But we also need to find ways to mitigate and adapt to a warming world. One way to do that is to plant vegetation – and that’s exactly what one hallmark project is aiming to do. Enter the Great Green Wall, an initiative that aims to hold back the Sahara by restoring 100 million hectares of land across Africa by 2030. Once completed, it’ll consist of a greenbelt of trees, grasslands and vegetation approximately 15 kilometers wide and almost 8,000 kilometers long, stretching across 11 countries, from Senegal in the west all the way to Djibouti in the east. That’s approximately the same distance as from Portugal to India, or from New York to Rio de Janeiro. The project is coordinated by the United Nations through its Convention to Combat Desertification (UNCCD) and involves a total of 21 African countries. Aside from restoring much of the Sahel, it also aims to create 10 million green jobs to improve livelihoods in what is one of the poorest regions of the world.
So, what does the Great Green Wall actually look like on the ground? Let’s be clear about one thing: the initiative isn’t just about planting trees. What’s more important is to make the Sahel livable again for humans, animals and the rest of the ecosystem. That means planting the right types of vegetation in the right places, whether that’s trees, bushes or grass, and leaving it to local communities to regreen the Sahel from the bottom up. Because that’s something that’s already been happening in the Sahel for decades – long before the Great Green Wall even became a thing. Now we all know that when a tree gets cut down, it leaves behind a stump. But what you may not know is that these stumps can also grow back. And what farmers in Niger have been doing is regenerating a lot of trees from stumps and roots. It’s a technique called farmer-managed natural regeneration. The trees provide nutrients and keep the soil fertile for crops, as well as providing food, fodder and fuel for households and livestock.
Meanwhile in neighboring Burkina Faso, farmers have been restoring land by digging these deep pits known as zaï. The pits are filled with compost, and crops like sorghum and millet, as well as trees, can be grown inside them. This helps improve soil fertility and combat drought: the pits collect rainwater, the compost provides nutrients for the plants, and the trees enrich the soil for crops. Using these techniques, farmers have restored more than 5 million hectares of land in Niger alone. On top of that, they’re now growing an additional half a million tons of grain each year – enough to feed 2.5 million people. These local communities are the engine of restoration in the Sahel, and they have a crucially important role to play in building the Great Green Wall. So, how much of the Great Green Wall has actually been completed to this day? The answer is a little complicated. Officially, only about 4 million hectares of land have been restored, which is about 4% of the target. But once you factor in all of the restoration that’s been carried out in the wider Sahel region, including independent work by local farmers, that figure rises to just under 18 million hectares, or 18%. Either way, it’s not a lot of progress. Communities in the Sahel will have to restore an additional 8 million hectares per year to finish the Great Green Wall by 2030. That’s around 20 times the current rate of progress. One of the main obstacles has been a lack of funding.
At the end of 2020, the project had received just $1 billion, compared to the roughly $33 billion needed according to UNCCD. In Senegal, for example, some of that money has been going to local communities to fund schools and solar energy projects in exchange for their involvement in restoration work. But some villagers say they haven’t been paid in months. Armed conflict and terrorism pose another major challenge. The situation in Burkina Faso has become so dangerous that the Great Green Wall initiative has stopped investing in the country entirely. But there’s good news, too: this January, the Great Green Wall received $14 billion in new funding from partners including the African Development Bank, the World Bank and the European Commission.
While that money won’t solve the underlying challenges facing the Sahel, it’s still a massive step in the right direction. It won’t quite make the Sahara green again, but it might just stop it from growing any further. What do you think our world leaders can do to make the Great Green Wall a reality? Let us know in the comments. And if you enjoyed this video, please remember to hit that like button and subscribe for more content from Landscape TV.
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