From Carbon Sink to Carbon Source: The Crisis of Africa’s Forests
Introduction
For decades, the planet’s tropical forests - including those in Africa - have been celebrated as one of our most powerful natural defenses against climate change. By absorbing carbon dioxide (CO₂) during photosynthesis and storing it as biomass, they acted as “carbon sinks,” helping to stabilize atmospheric greenhouse gas levels. But a recent breakthrough study reveals a disturbing shift: Africa’s forests and woody savannas are now emitting more carbon than they absorb.
This reversal has massive implications - not only for Africa but for the entire world’s efforts to meet climate goals. In this article, we explore what the study found, why this shift happened, its consequences for global climate policy, and what must be done to reverse course.
What the Science Says: Africa’s Forests Are Now a Carbon Source
A new peer-reviewed study published in the journal Scientific Reports (November 2025) has documented a continent-wide shift in the carbon balance of African forests. Using high-resolution satellite-derived biomass maps, machine-learning algorithms, and ground-based validation plots, researchers tracked changes in “aboveground woody biomass” across Africa between 2007 and 2017.
Key Findings
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Between 2007 and 2010, Africa’s forests had a net gain of biomass - about 439 ± 66 teragrams (Tg) per year.
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However, from 2010 to 2015, the continent experienced a sharp biomass decline of −132 ± 20 Tg/yr, and from 2015 to 2017 a further loss of −41 ± 6 Tg/yr.
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Overall, that amounts to a loss of roughly 106 billion kilograms of forest biomass per year - roughly equivalent to the weight of 106 million cars.
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The losses have been especially severe in tropical moist broadleaf forests, concentrated in regions such as the Congo Basin, parts of West Africa, and Madagascar.
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While some savanna areas saw increases in woody vegetation (perhaps due to shrub encroachment), these gains were far too limited to offset the extensive forest losses.
In short: what was once a net carbon sink has now become, as a whole, a net carbon source. The consequences are profound for both climate mitigation and biodiversity.
What Drove This Reversal? Underlying Causes of Forest Loss
Understanding why Africa’s forests flipped from sink to source requires looking at several interrelated drivers. The study authors - and subsequent analyses - point to the following:
1. Deforestation and Forest Degradation
The primary driver is large-scale forest loss in tropical moist broadleaf forests, especially in the Congo Basin, West Africa and Madagascar. Logging, land clearance for agriculture, infrastructure development, and mining contribute significantly to the removal of trees and degradation of intact forests.
Forest degradation - not just outright deforestation - also plays a major role. Trees may be partially removed or damaged, reducing biomass and carbon storage capacity over time.
2. Agricultural Expansion & Land-Use Change
Increasing demand for farmland, fuelwood, and timber drives forest clearing. Small-scale agriculture, shifting cultivation, and expansion into forested regions remain widespread, especially where governance is weak and economic pressures high.
3. Population Growth, Poverty & Fuelwood Dependence
In many regions, rural communities rely on wood for cooking and heating. With high population growth and limited access to alternative energy, the pressure on forests remains acute. The result: continual biomass extraction without sustainable management. While the latest large-scale study does not detail socio-economic factors for every region, these human pressures underlie much of the deforestation and degradation.
4. Weak Governance, Illegal Logging and Lack of Enforcement
In many countries, forest governance is under-resourced. Illegal logging and unregulated clearance for agriculture or infrastructure often escape oversight. The lack of effective enforcement mechanisms means forests are cleared or degraded with impunity. The scientists behind the study highlight that “stronger forest governance, enforcement against illegal logging, and large-scale restoration programmes” are urgently needed.
5. Insufficient Forest Restoration and Conservation Efforts
While some initiatives - like the pledge under AFR100 (African Forest Restoration initiative) aim to restore degraded lands and forests, current restoration efforts remain too limited in scale and funding to compensate for the massive losses in intact forest biomass.
What This Means for Global Climate, Biodiversity & Communities
The shift of Africa’s forests from carbon sinks to sources has cascading implications, from planetary carbon budgets to human livelihoods.
🌐 Impact on Global Climate Goals
Forests worldwide - especially tropical forests - have played a crucial role in absorbing CO₂ emissions from fossil fuels and land use. The fact that Africa’s forests are now releasing carbon undermines one of the last major natural buffers against climate change. As the lead author from the research team puts it: “This is a critical wake-up call for global climate policy.”
Because the world was counting on tropical forests (Amazon, Southeast Asia, Africa) to continue acting as carbon sinks, this turn complicates efforts to meet the targets under the Paris Agreement - particularly the more ambitious goal of limiting global warming to 1.5 °C. To compensate for lost forest sequestration, reductions in fossil fuel emissions would need to be even deeper and faster.
🌱 Blow to Biodiversity and Ecosystem Services
It’s not just about carbon. Forests - especially tropical rainforests - are home to vast biodiversity, unique ecosystems, and provide critical services such as water regulation, soil fertility, and climate moderation. Continued forest loss threatens species extinction, disrupts water cycles, and destabilizes regional climates. For example: the Congo Basin Rainforest is often called the “water-pump” of Africa - its forests help regulate rainfall and climate conditions across the continent.
🌍 Impacts for Local Communities & Food Systems
Many African communities rely on forests for livelihoods: agriculture, fuelwood, hunting, medicinal plants and more. Forest loss reduces access to forest resources, undermines traditional ways of life and may force migration or shift communities into more precarious economic and social conditions.
Moreover, with forest degradation and deforestation, ecosystem services like rainfall regulation and soil health can diminish - threatening agriculture, water supply and stability.
Global Carbon Market & Climate Finance Risks
The findings also challenge assumptions underpinning carbon offset projects: if forests are no longer reliably storing carbon, then many carbon-credit schemes that assume forest permanence may be invalid. As one of the study co-authors noted, this new data “provides critical risk data … for the wider voluntary carbon market (VCM).”
This adds urgency to ensure that carbon credits or offset programmes are underpinned by robust, accurate, and up-to-date data - not outdated assumptions.
What Can Be Done: Solutions and Opportunities
While the situation is alarming, it’s not hopeless. The study's authors and environmental stakeholders suggest several strategies - and if implemented at scale, these could help restore Africa’s forests and safeguard global climate and biodiversity.
1. Strengthen Forest Governance and Enforcement
This needs to be among the top priorities. Governments - African and global - must commit to better laws, more consistent enforcement, stronger anti-illegal logging efforts, and transparent monitoring. This includes supporting local communities, forest rangers, remote monitoring, and accountability for deforestation.
International cooperation and financing are critical. Without support from the global north countries and institutions, many African nations lack the resources to properly protect their forests.
2. Scale up Restoration & Reforestation Initiatives
Initiatives such as AFR100 provide a blueprint: restoring degraded lands, planting native species, rebuilding ecosystems, and supporting regenerative land-use models. These efforts need to be scaled rapidly, with secure funding, long-term commitments, and community involvement.
Beyond tree planting, restoration should include nurturing diverse native forests (not monoculture), restoring soil health, protecting biodiversity, and considering ecosystem complexity.
3. Align Climate Finance and Carbon Markets with Reality
Carbon offset programmes, voluntary carbon markets, and international finance initiatives must update their assumptions to be based on recent science. Carbon credits should only be issued when long-term forest permanence is verifiable, and projects should incorporate rigorous monitoring, transparency and social safeguards.
Financial support - especially for countries and communities that would otherwise rely on deforestation for income - must be substantial and sustained. Mechanisms like the proposed Tropical Forests Forever Facility (TFFF); which aims to pay countries to preserve forests - must be fully funded and implemented.
4. Promote Sustainable Land-Use & Alternative Livelihoods
Communities living near forests often clear land for agriculture, fuel, or building materials because they lack alternatives. Providing sustainable livelihoods - agroforestry, sustainable agriculture, non-timber forest products, forest-friendly tourism, renewable energy - can reduce pressure on forests.
Supporting education and infrastructure for clean energy and alternative income streams can help to align human needs with forest conservation.
5. Raise Global Awareness & Political Will
The shift from sink to source must become part of the global climate narrative. International summits, climate negotiations, environmental media, NGOs, and civil society must highlight this paradigm change to mobilize resources, pressure governments, and ensure policy action.
Public awareness can also pressure consumer-facing industries (timber, palm oil, mining, agriculture) to commit to deforestation-free sourcing and support forest protection.
Why This Matters for Us - and for the Planet
As the world tries to transition away from fossil fuels and cut emissions, it has often counted on forests, especially tropical forests, to absorb CO₂. The new reality challenges that assumption. If Africa’s forests remain a carbon source, the amount of CO₂ we must cut from energy, transport, and industry becomes even larger.
In other words: it raises the bar for global climate ambition. It also underscores that conservation, protecting existing forests - is just as important (if not more so) than reforestation. And it reminds us that social justice, development, climate, biodiversity and economic interests are deeply intertwined.
For anyone interested in environmental justice, climate solutions and sustainable development: this isn’t just a story about trees. It’s a signal that the global climate strategy needs urgent recalibration; starting with Africa.
Conclusion
The new 2025 study revealing that Africa’s forests have transitioned from a carbon sink to a net carbon source is a watershed moment in climate science. It underlines the urgency of global forest protection, stronger governance, better financing, ecological restoration, and sustainable land-use transformation.
But with urgency comes opportunity. If we - governments, communities, businesses, investors and citizens act fast and collaboratively, we can still reverse the trend. We can restore forests, protect biodiversity, secure livelihoods, and renew one of humanity’s greatest natural climate allies.
The alternative - letting forests continue to fall, is a world where climate targets slip further out of reach, biodiversity crumbles, and vulnerable communities pay the highest price. The time to act is now.
Sources & References
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The Guardian – Africa’s Forests Shift from Carbon Sink to Carbon Source
https://www.theguardian.com/environment/2025/nov/28/africa-forests-transformed-carbon-sink-carbon-source-study -
PubMed – Satellite-Based Study on Africa’s Aboveground Woody Biomass (Scientific Reports)
https://pubmed.ncbi.nlm.nih.gov/41315646/ -
Down To Earth – Africa’s Forests Transition to Net Carbon Source
https://www.downtoearth.org.in/forests/africas-forests-transitioned-from-carbon-sink-to-net-carbon-source -
Phys.org – Africa’s Forests Now Emit More Carbon Than They Absorb
https://phys.org/news/2025-11-africa-forests-absorbing-emitting-carbon.html -
MDPI – Forest Degradation and Biomass Studies (Related Context)
https://www.mdpi.com/2571-6255/8/8/333 -
Sputnik Africa – Agricultural Expansion & Land Use Pressure
https://en.sputniknews.africa/20251129/1080971573.html -
University of Leicester – Research Summary & Climate-Finance Implications
https://le.ac.uk/news/2025/november/africa-forests-absorbing-emitting-carbon -
The Guardian – Congo Basin Rainforest & Climate Research Funding Challenges
https://www.theguardian.com/environment/2025/nov/18/congo-basin-rainforest-africa-research-funding-aoe
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