• Nature study shows forests now emit more carbon than they absorb
• Researchers link the shift to widespread deforestation driven by humans
• Report urges urgent policies to halt forest loss and restore ecosystems

African forests, once crucial allies in the global fight against climate change, have shifted from being carbon sinks to becoming net sources of carbon due to rising deforestation driven by human activity, according to a report published on November 28 in the scientific journal Nature.

Titled “Loss of tropical moist broadleaf forest has turned Africa’s forests from a carbon sink into a source,” the report tracks changes in aboveground forest biomass—carbon stored in trees and woody vegetation—over ten years using satellite data and advanced machine learning models.

The research, conducted by a team from several European universities, including Leicester, Sheffield, and Helsinki, draws on data from NASA’s Global Ecosystem Dynamics Investigation (GEDI) laser instrument and Japan’s ALOS radar satellites, combined with thousands of on-the-ground forest measurements. The result is the most detailed map to date of biomass changes across Africa over a decade, with resolution fine enough to show local deforestation patterns.

The study found that Africa absorbed more carbon than it emitted between 2007 and 2010, largely due to its tropical forests. But since then, widespread deforestation has reversed the trend, making the continent a net emitter of CO2. Between 2010 and 2017, African forests lost about 106 million tons of biomass each year, roughly the weight of 106 million cars. As a result, these forests now release more carbon than they remove.

Urgent action needed

The tropical moist broadleaf forests of the Democratic Republic of Congo, Madagascar, and parts of West Africa were the most affected. Gains in savanna regions from shrub growth were not enough to offset losses elsewhere.

Human activity is the main driver of this shift. Farmers are clearing more land for food production, while infrastructure projects and mining accelerate vegetation loss and weaken ecosystem resilience.

The authors call for urgent action to protect the planet’s natural climate stabilizers. They urge leaders to implement policies to end global deforestation, as required by the Glasgow Leaders’ Declaration on Forests and Land Use, adopted at COP26 in 2021. They also call for new targeted restoration initiatives similar to REDD+ and for revisions to countries’ nationally determined contributions under the Paris Agreement to make up for the continued loss of natural carbon sinks.

Walid Kéfi