Africa’s forests, long regarded as one of the world’s most important natural carbon sinks, are now releasing more carbon into the atmosphere than they absorb, according to a new international study led by scientists at the University of Leicester. The findings suggest that large-scale forest loss across the continent has pushed African forests past a critical threshold, weakening their role in slowing global climate change.
The research, published in the journal Scientific Reports analysed changes in aboveground forest biomass across Africa using satellite observations, machine learning techniques and field measurements collected over more than a decade. Scientists found that while African forests gained carbon between 2007 and 2010, the trend reversed sharply after 2010 as deforestation and forest degradation intensified.
Between 2010 and 2017, Africa lost an estimated 106 billion kilograms of forest biomass every year, the study found. This loss was concentrated mainly in tropical moist broadleaf forests, particularly in the Democratic Republic of Congo, Madagascar and parts of West Africa. Although some savanna regions showed modest gains due to increased shrub growth, these increases were insufficient to offset widespread forest losses elsewhere.
Forest biomass represents the amount of carbon stored in trees and woody vegetation. A decline in biomass therefore indicates a net release of carbon dioxide into the atmosphere. According to the researchers, this shift means Africa’s forests are no longer functioning as a net carbon sink, but have instead become a source of emissions.
Professor Heiko Balzter, senior author of the study and Director of the Institute for Environmental Futures at the University of Leicester, said the findings carry serious implications for global climate targets. He warned that if Africa’s forests continue to lose carbon, deeper emission cuts will be required elsewhere to keep global warming within the limits set by the Paris Agreement.
The study combined data from NASA’s Global Ecosystem Dynamics Investigation laser instrument and radar observations from Japan’s Advanced Land Observing Satellite, along with thousands of on-the-ground forest measurements. Together, these datasets allowed researchers to track forest biomass changes at a local scale across the continent, producing the most detailed assessment of Africa’s forest carbon balance to date.
The findings come amid renewed international focus on forest protection following announcements at the COP30 Climate Summit, including the launch of the Tropical Forests Forever Facility, which aims to mobilise climate finance to support forest conservation in tropical countries. Researchers said the results underline the urgency of halting deforestation if forests are to remain effective in regulating the Earth’s climate.
Dr Nezha Acil, a co-author of the study from the National Centre for Earth Observation, said stronger forest governance, action against illegal logging and large-scale restoration initiatives such as Africa’s AFR100 programme could help reverse the damage. AFR100 aims to restore 100 million hectares of degraded land across the continent by 2030.
Another co-author, Dr Pedro Rodríguez-Veiga, said the findings also have implications for global carbon markets, warning that continued forest loss in Africa could undermine international efforts to offset emissions through nature-based solutions.
The researchers concluded that without urgent and sustained action to protect and restore forests, Africa risks losing one of its most valuable defences against climate change, with consequences that would be felt far beyond the continent.