Two great green walls to stop global desertification

China has already planted 66,000 million trees to stop the advance of the Gobi desert and now Africa, with the support of the UN, wants to grow the longest living structure in the world. Two monumental green projects for the two continents where desertification is advancing the most

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A woman shielding herself from strong winds during a sandstorm on March 15, 2021 in Beijing. The Chinese capital and the northern part of the country received a sandstorm Monday that sent PM 2.5 and PM 10 air quality indexes soaring into the thousands and forced the cancellation of air quality.

China's Green Wall

Three-North Shelter Forest Program

Desertification is a process of land degradation - the process of land becoming infertile - that has been growing for years all over the world due to climatic causes and the direct effect of human action, such as deforestation, grazing and other practices that deplete water resources. In places like China, however, desertification also means literally the advance of the desert, which eats away at the land year after year. The Gobi desert is getting closer and closer to Beijing, contributing to increasingly intense sandstorms over the Chinese capital, leaving apocalyptic images like those of 15 March, with orange skies and pollution that exceeds up to 160 times the recommended limits for health.

About 28% of China's land area is desert, and the Chinese government has been fighting for years to prevent this figure from rising. To slow the advance of the Gobi desert, China launched its Great Green Wall project back in 1978: a barrier of trees that, when completed in 2050, will be 4,500 kilometres long. It will run the length of northern China, near the Mongolian border, from China's easternmost province, Heilongjiang, to its westernmost province, Xinjiang. So far, 66 billion trees have already been planted out of a planned 88 billion.

Average annual change in green area. Percentages throughout 2000 to 2017

The results of this enormous work are already visible from NASA satellites, which calculates that a quarter of the new green area that the planet gains each year is planted in China: it is the country that afforests the most in the world. In 40 years China has cultivated 30 million hectares of forest, which has increased the country's green area from 5% to 13%. When it is finished, the Great Green Wall of China will have increased the world's forests by 10%.


Africa's Green Wall

The Great Green Wall, in the Sahel zone

A powerful competitor has emerged to the Chinese megaproject, the Great Green Wall of Africa, which wants to stop the advance of the Sahara desert, the largest in the world. The aim is to plant trees along 8,000 kilometers from one end to the other (from east to west) of the African continent, passing through 11 different countries. If completed, it would be the longest living structure on the planet, three times longer than the Great Barrier Reef.

Satellite image clearly showing the vast expanse of the Sahara Desert.

The project was launched in 2007 and has already advanced by 15%, but it has been in recent months that has gained momentum and has become a more holistic initiative, which seeks to restore life to desertified areas of land and at the same time contribute to food security for millions of people and provide jobs for millions more. The UN, the African Union, the EU, the World Bank and FAO, among others, have joined forces to make it a reality. The final impetus came out of the One Planet Summit, launched by French President Emmanuel Macron on January 11, 2021. It secured pledges of €14.3 billion in donations by 2025. But an estimated 27 billion euros are needed by 2030 to restore 100 million hectares of desertified land, with a natural extension (not just trees) that would capture 250 million tonnes of carbon and create 10 million jobs.

A man walks along a road through the desert in Mauritania, between the capital, Nouakchott, and the coastal trading town of Nouadhibou.

In the Sahel, one of the regions of the planet most affected by the climate crisis, this Great Green Wall aims to combat both the great global emergency and others that plague Africa, such as hunger, conflict, and migration.

Infographics in the ARA Diumenge paper

Mockup MurallesVerdes

Sources: NASA, FAO, USGS and own elaboration.