Africa’s forests, long a key player in soaking up carbon dioxide from the atmosphere, have flipped to releasing more carbon than they store.
New research shows that between 2010 and 2017, the continent’s forests and woody savannas lost an average of about 106 billion kilograms of aboveground biomass each year — the equivalent of roughly 106 million cars’ worth of plant material. This shift turned Africa from a net absorber of carbon into a net emitter, driven largely by deforestation in lush tropical rainforests, researchers report in Scientific Reports.
“This is a critical wake-up call for global climate policy,” says Heiko Balzter, a researcher at the University of Leicester in the U.K. and senior author of the study.
Africa’s ecosystems have always been important in the planet’s carbon cycle, pulling in about 20 percent of the world’s carbon through plant growth while also releasing some through fires and land clearing. But pressures from human activities, like farming expansion and logging, have been mounting. Past studies gave mixed signals on whether the continent was overall gaining or losing carbon, with some suggesting a steady state or even a small sink.
To get a clearer picture, the team turned to advanced satellite tools. They used laser measurements from NASA’s GEDI instrument on the International Space Station and radar data from Japan’s ALOS satellites, combined with machine learning algorithms. These helped create detailed maps of aboveground biomass — the carbon-rich wood in trees and shrubs — at a fine 100-meter resolution across Africa from 2007 to 2017. The maps were checked against thousands of on-the-ground measurements from field plots and airborne scans for accuracy.
The results revealed a clear turning point. From 2007 to 2010, Africa added about 439 billion kilograms of biomass per year overall. But after 2010, losses took over, with tropical moist broadleaf forests in places like the Democratic Republic of Congo, Madagascar, and West Africa hit hardest by deforestation. Savannas saw some gains, likely from bushes spreading due to rising carbon dioxide levels favoring woody plants over grasses, but it wasn’t enough to balance the scales.
The shift means the world now has one less natural helper in fighting climate change, widening the gap in efforts to limit global warming under the Paris Agreement.
“Stronger forest governance, enforcement against illegal logging, and large-scale restoration programs such as AFR100, which aims to restore 100 million hectares of African landscapes by 2030, can make a huge difference in reversing the damage done,” says Nezha Acil, a co-author from the National Centre for Earth Observation at the University of Leicester.
While the study focused on aboveground biomass and didn’t track soil carbon or short-term fluxes like litter decay, the findings highlight the need for urgent steps, like the new Tropical Forests Forever Facility announced at the recent COP30 summit, to protect these vital areas.
Citation: H. Balzter et al. “Loss of Tropical Moist Broadleaf Forest Has Turned Africa’S Forests from a Carbon Sink into a Source.” Scientific Reports. November 2025. DOI: 10.1038/s41598-025-27462-3
