An AI Discovered Nearly 2 Billion Trees in the Sahara Desert

The world is not as inhospitable as we thought. "I think it marks the beginning of a new scientific era.”
Brad Bergan
University of Copenhagen

There are more trees in the West African Sahara Desert than we thought — a lot more. Just last year, a study based on AI and satellite imagery was published in the journal Nature. In it, researchers say they found nearly two billion living trees in the Sahara Desert.

All-in-all, researchers counted about 1.8 billion trees and shrubs in the 501,933 square-mile (1.3 million square-kilometer) area. The area encompasses the western-most region of the Sahara Desert, called the Sahel, along with the sub-humid zones of West Africa.

"We were very surprised to see that quite a few trees actually grow in the Sahara Desert, because up until now, most people thought that virtually none existed," said Professor Martin Brandt from the University of Copenhagen and the lead author of the recent study.

"We counted hundreds of millions of trees in the desert alone. Doing so wouldn't have been possible without this technology," explained Brandt, according to a blog post on the University of Copenhagen's website. "Indeed, I think it marks the beginning of a new scientific era."

Desert trees. Via Unsplash/Martin Brandt

AI tree detection could suggest new carbon budget factors

The researchers used uncommonly detailed satellite imagery from NASA, along with deep learning — an advanced mode of AI. Typical satellite imagery can't identify single trees, which makes them invisible to ordinary means.

Additionally, limited interest in counting the number of trees outside of forests has led many to think this desert region has almost no trees whatsoever. But now we have proof showing how wrong they were.

Extra knowledge about trees in dry areas like the Sahara Desert is significant for multiple reasons, said Brandt. For one, they hint at the existence of an unknown factor for nations and companies considering their global carbon budget.

"Trees outside of forested areas are usually not included in climate models, and we know very little about their carbon stocks. They are basically a white spot on maps and an unknown component in the global carbon cycle," added Brandt.

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AI will help us better grasp the Earth's ecosystem

Moreover, the recent study improves our comprehension of how crucial trees are for biodiverse ecosystems — not to mention the people living in these environments. A firmer grasp of the science of trees is critical for programs developing agroforestry — a force of major socioeconomic and environmental gravity amid arid regions, reports The World Economic Forum.

"Thus, we are also interested in using satellites to determine tree species, as tree types are significant in relation to their value to local populations who use wood resources as part of their livelihoods," said Professor Rasmus Fensholt of the geosciences and natural resource management department at the University of Copenhagen.

"Trees and their fruit are consumed by both livestock and humans, and when preserved in the fields, trees have a positive effect on crop yields because they improve the balance of water and nutrients," added Fensholt.

As the ecosystem of the planet shifts into phases less friendly to human biology, other species of life may also suffer. For humans to become better custodians of the Earth's biosphere, systems like the researchers' deep-learning AI will scale up our ability to grasp the global ecosystem — to take more precise measures against the climate crisis, but also to estimate the damage.