Using high-resolution, commercial satellite images and AI, an international team of scientists, including researchers from NASA, marked almost 10 billion individual trees in Africa's dryland to determine the quantity of carbon outside the dense tropical forests of the continent.
It resulted in the first comprehensive estimate of tree carbon density in Africa's Sahel, Saharan, and Sudanian zones. The team reported its findings on March 1 in Nature, and the data are free and available for the general public.
The researchers found that the tree population across the semi-arid region of Africa is way more than previously believed. However, the quantity of carbon stored is less than the prediction of a few models. In recent studies, the team estimated that African Dryland lock-up around 0.84 pentagrams of carbon (1 pentagram is equal to 1 million metric tons).
"Our team gathered and analyzed carbon data down to the individual tree level across the vast semi-arid regions of Africa or elsewhere – something that had previously been done only on small, local scales," said Compton Tucker, lead scientist on the project and an Earth scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Past satellite-based estimates of tree carbon in Africa's drylands often mistook shrubs and grasses for trees. "That led to over-predictions of the carbon there."
Carbon constantly fluctuates between the land, the ocean, the atmosphere, and the back. During the process of photosynthesis, trees tend to remove a greenhouse gas, Carbon Dioxide, from the atmosphere of the Earth and store it in their leaves, branches, trunks, and roots; for this particular reason why increasing tree cover is often suggested as a way to deal with continuously growing carbon emissions.