Africa's forests become net carbon source, threatening planet's climate balance: Study

• Forests alongside oceans represent world's foremost carbon sinks, where plants store absorbed carbon dioxide, Prof. Doganay Tolunay tells Anadolu
• Deforestation rates in South America surpass those in Africa, with the region losing 4.2M hectares annually over the past decade, and Brazil accounting for 2.9M hectares yearly

ANKARA

Africa's forests have shifted from absorbing carbon to becoming a net carbon source after 2010 due to extensive losses of tropical moist broadleaf forests, researchers warn.

A new study published in the Nature Portfolio journal in November reveals that Africa's forests and woody savannas switched from carbon sink to net source between 2010 and 2017 due to the widespread loss of tropical moist broadleaf forests.

Using NASA's GEDI Lidar, Japan's ALOS radar satellites, and ground data, the team mapped aboveground biomass changes across African biomes for more than a decade.

Driven by deforestation and forest degradation, the most significant biomass declines occurred in countries such as the Democratic Republic of Congo, Madagascar, and parts of West Africa.

Declining carbon stocks and global deforestation trends

Professor Doganay Tolunay from Istanbul University's Forest Engineering Department shared insights with Anadolu, explaining that forests alongside oceans represent the world's foremost carbon sinks, where plants store absorbed carbon dioxide through growth on an annual basis.

According to the Global Carbon Budget, terrestrial ecosystems absorb roughly 2.4 billion tons of carbon from the atmosphere each year, while oceans take in 3.2 billion tons and forests contribute about 1.3 billion tons.

Tolunay noted that in total, natural sinks absorb about 5.6 billion tons of carbon each year, equivalent to 20.5 billion tons of CO₂. This is a key benchmark for the 2050 net-zero target, as ecosystems must offset annual emissions that exceed 60 billion tons of CO₂ equivalent.

UN’s Food and Agriculture Organization data shows that carbon stocks in African forests dropped from 132 billion tons in 1990 to 115 billion tons in 2025 as deforestation persists across continents, albeit at a decelerating rate.

Tolunay shared that global deforestation averaged 17.6 million hectares per year from 1990 to 2000, declined to 13.6 million hectares between 2000 and 2015, and further fell to 10.9 million hectares from 2015 to 2025, with 90% of losses in tropical forests driven by agriculture, mining, and urbanization.

He also pointed out that for every hectare of forest lost globally, an average of 0.3 to 0.4 tons less carbon gets stored in the atmosphere each year.

Deforestation rates in South America

Deforestation rates in South America surpass those in Africa, with the region losing 4.2 million hectares annually over the past decade, including 2.9 million hectares by Brazil alone, he said, adding that despite deforestation being a key topic at COP30 in Brazil this year, no binding decisions emerged on financing related to halting it.

Tolunay warned that ongoing ecosystem destruction would render the 2050 net-zero emissions target unattainable, potentially leading to global temperature increases of 3 to 4 degrees Celsius (37 to 39 Fahrenheit) by century's end if warming exceeds 2 degrees above pre-industrial levels.

In addition to curbing greenhouse gas emissions from fossil fuels from industry, agriculture, and waste, he stressed the vital importance of preventing deforestation and ecosystem degradation.

Tolunay recalled that two-thirds of greenhouse gas emissions from 1850 to 2011 stemmed from fossil fuels, while one-third resulted from deforestation, often linked to converting forests into agricultural land.

He also highlighted that deforestation could trigger new epidemics and diseases.

To enhance the roles trees play in carbon storage, Tolunay advocated monitoring infrastructure, settlement, and mining projects that might cause deforestation to save forested areas.

He further emphasized limiting timber production in forests and ensuring climate and soil conditions suit tree cultivation for successful reforestation efforts.

COP31 and a fresh perspective

In recent years, improved forest management approaches have gained prominence, focusing on boosting carbon stocks in forests or reducing greenhouse gas emissions from forestry activities beyond standard practices.

Tolunay stated that key goals of improved forest management include preventing and mitigating forest fires while safeguarding biodiversity.

He suggested that addressing biodiversity and climate change jointly at the 31st UN climate change conference (COP31), to be hosted by Türkiye next year, could introduce a fresh perspective compared to recent conferences that focused primarily on financing.

Warning that Africa’s reversal from carbon sink to source weakens global efforts under the Paris Agreement, Tolunay called for urgent climate finance, stronger forest governance, and large-scale restoration to protect this vital natural buffer against climate change.