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.