The Great Green Wall of Africa is Changing Millions of Lives

The Happy Neuron
Jul 10, 2019 · 4 min read
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Once complete, the Great Green Wall of Africa will stretch 8000 km from Senegal to Djibouti, east-west across the entire continent of Africa, making it the largest living structure on the planet and saving the lives of tens of millions of people.

Originally designed in 2007 to be a 15 km wide band of trees and vegetation to stop the desertification of the Sahel region in sub-Saharan Africa, it has now grown far beyond its initial inception. With the help of more than 20 international organizations and governments, the project includes the ambitious goals of increasing employment, promoting renewable energy, reducing violence, ensuring food security, and many more, all of which are desperately needed, as the Sahel is considered to be among the poorest areas in the world and the hardest hit by climate change.

One of the key tools making this possible is the open source software Collect Earth, a collaboration between Google and the UN Food and Agriculture Organization (UN FAO), which depends on a groundbreaking technique called augmented visual interpretation.

Desertification and the Sahel

Desertification is the process by which productive land becomes infertile through climate variations and poor land management. If weather patterns shift and long-term droughts ensue, coupled with human activity such as deforestation, overfarming, or allowing livestock overgrazing, once lush areas might become barren in a short time. Heavily populated areas on the edge of a desert are at a far higher risk of falling victim to desertification, as the area is already prone to droughts and the land is already overused.

Globally, this a major threat, especially if the climate continues to shift. According to the UN Convention to Combat Desertification, “12 million hectares of land are degraded through drought and the encroachment of the desert — this is 23 hectares per minute! — where 20 million tons of grain could have been grown.”

Desertification has caused innumerable problems in the Sahel. The UN estimates 80% of the land has already been degraded, which puts tens of millions at risk of starvation, causes political instability, forces large-scale displacement of people, devastates local economies, etc. Because of this, the situation in the Sahel has been dubbed the worst humanitarian crisis since 1945, forcing an estimated 60 million people to migrate out of the area by 2020.

Building the Wall

At first, the idea seemed simple: plant millions of trees on the southern border of the Sahara to rejuvenate the land and stop desertification, but it soon became apparent that the situation was far more complicated. For starters, how would these trees survive? As Yammama, a member of the National Forest Conservation Council of Nigeria, stated “You can’t plant a tree in the desert without a water source and expect people who are struggling for water for their human needs to shoulder the extra burden of watering it.” It soon became clear that it’s going to take much more.

The solution is a bottom-up approach, in which the focus is no longer on forestry but on innovative techniques in water conservation, sustainable farming, reintroducing indigenous animals, etc., with each community determining its own course of action. This also includes developing local industries to support these initiatives, such as Shea Butter production in Burkina Faso, which now plays a major role in sustainable development of the region.

The French Scientific Committee on Desertification explains the goal 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.”

Collect Earth

A project of this size, of course, needs maps — lots and lots of detailed maps, along with the algorithms to analyze them. A collaboration between Google, the UN Food and Agriculture Organization, and numerous other partners, Collect Earth facilitates access to several archives of satellite imagery, which, according to a recently published paper, “offer free access to an unparalleled amount of information on current and past land dynamics for any location in the world.”

Of course, this vast amount of information needs to be processed to determine the areas still in need and to assess the impact of efforts already taken. Considered a drastic improvement over standard remote sensing, augmented visual interpretation does this by comparing multiple images of the same area with different resolutions, across different seasons and years, and supplemented with years worth of graphs and indices created automatically by algorithms. Virtually every change to a piece of land can be charted, prompting the UN FAO to deem Collect Earth and augmented visual interpretation an integral part of building the Great Green Wall of Africa.

The idea of stopping the desertification of the Sahel goes back several decades, and many different solutions have been proposed. However, they all lacked the technology to bring them to fruition. Today, thanks to the incredible leaps in technology in recent years, a lot of progress has been made on a once impossible problem. The UN Convention to Combat Desertification claims that over 11 million trees have been planted in Senegal, more than 20,000 jobs have been created in Nigeria, and roughly 15 million hectares of unusable land has been restored. While there is still a lot of work to do and many problems to overcome the Great Green Wall is on it’s way to realizing “its full potential as a lifeline for the Continent’s poorest people, not just to survive but to thrive once more on their ancestral lands.”

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Originally published at on July 10, 2019.

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