Africa’s vast forests, once crucial for absorbing carbon from the atmosphere, are undergoing a serious transformation. Recent research shows that they now release more carbon dioxide than they capture, a reversal that began around 2010 and is making the global fight against climate change far more difficult. This shift, driven mainly by deforestation in tropical regions, demands urgent attention from policymakers across the world.
Getting to Know the Carbon Sink Transition
When trees grow, they pull in CO2 and store it in their leaves and wood, turning forests into carbon sinks. For many years, African ecosystems, especially the rainforests in the Congo Basin, played this role, absorbing roughly 20% of the world’s land-based carbon removals each year. From 2007 to 2010, the continent’s aboveground woody biomass increased by about 439 million metric tons annually, which strengthened its status as a carbon sink.
Then, from 2010 onward, the pattern reversed.
- By 2015–2017, aboveground biomass had declined by about 41 million metric tons per year.
- Forests switched from being net absorbers of carbon to net sources of emissions.
This change matters because these forests are more than just collections of trees; they’re natural shields against climate change. When they flip from sink to source, more CO2 remains in the atmosphere, speeding up global warming, almost like Africa’s lungs starting to breathe out instead of in.
Researchers pieced this story together using satellite data from instruments such as NASA’s GEDI LiDAR, which measures tree height from space, along with radar imagery. They created biomass maps for the entire continent at a fine 100‑meter resolution and checked their results against ground plots and airborne scans. The findings reveal a clear tipping point, where losses in key regions began to outweigh gains.
Changes in Africa’s Forest Biomass Over Time
Data from the early 2000s suggested relative stability, but the real turning point came after 2007. Between 2007 and 2010:
- Biomass gains averaged +439 ± 66 teragrams per year.
- Most of these increases occurred in moist broadleaf forests.
- Savannas also contributed as shrubs expanded and added woody biomass.
After 2010, the situation shifted dramatically.
- From 2010 to 2015, net losses reached -132 ± 20 teragrams per year.
- From 2015 to 2017, net losses were still around -41 ± 6 teragrams annually.
The largest declines were found in tropical moist broadleaf forests that host dense rainforests. These areas shifted from gaining about 192 teragrams of biomass before 2010 to losing roughly 154 teragrams in the following years. Savannas, by contrast, showed some recovery as shrubs spread more widely, possibly because higher CO2 levels favored woody plants over grasses.
By 2017:
- Total aboveground woody biomass was estimated at around 118 petagrams.
- This equates to roughly 59 petagrams of carbon stored.
These figures are broadly consistent with earlier estimates, but they highlight just how fragile the system has become. Although data gaps between 2011 and 2014 exist due to satellite limitations, the overall trend remains clear: human activity can rapidly undo years of natural recovery, turning a decade of progress into a setback.
Key accelerators around this period included:
- Strong population growth and rising resource demands.
- Higher global commodity prices that increased pressure on land and forests.
Main Reasons for the Rise in Deforestation
The primary driver is deforestation. After 2010, forest cover loss in tropical moist broadleaf zones increased sharply, especially in:
- The Democratic Republic of Congo (DRC)
- Madagascar
- Several West African countries
Large areas have been cleared for:
- Logging and timber extraction
- Mining projects
- Agricultural expansion, including palm oil and soybean cultivation at forest edges
Agricultural growth explains a major share of the destruction. As Africa’s population rises, and is expected to double by 2050, farmers clear more land for crops and livestock. In the Congo Basin, small-scale shifting cultivation adds up at large scales, while commercial agriculture targets high-value exports. Charcoal production, a vital energy source for millions who lack access to electricity, is also stripping forests at a rapid pace.
Natural factors also play a role, though a smaller one compared to human actions.
- Fires, often intensified by longer dry spells linked to climate change, damage both savannas and forests.
- Repeated droughts in East Africa have thinned tree canopies, leaving them more vulnerable to disease and further stress.
Satellite analyses suggest that:
- Around 80–90% of observed biomass losses are directly tied to human activities.
Urbanization further contributes to forest decline. As cities such as Kinshasa expand, they spread into nearby forested areas for housing, roads, and infrastructure. Weak enforcement and limited capacity in some countries allow illegal logging to continue with little consequence. The result is not just trees being cut, but a web of pressures that slowly breaks down ecosystems that millions of people rely on.
At the local level, a villager in rural DRC might only cut a few trees for firewood, but when that behavior is multiplied across millions of households, the cumulative effect is enormous. These drivers interact, reinforcing each other and creating concentrated hotspots of rapid environmental change.
How Different African Biomes Are Being Affected
The impact of this transition varies across Africa’s diverse ecosystems.
Congo Basin Rainforests
The Congo Basin contains the largest continuous tropical rainforest outside the Amazon and holds the highest biomass on the continent.
- Dense, moist broadleaf forests can store up to about 429 megagrams of biomass per hectare.
- Between 2015 and 2017, this region alone lost around 154 teragrams of biomass per year.
- Losses were particularly intense along roads and rivers that ease access for logging and agriculture.
The DRC accounts for the majority of this trend, with forest loss rates climbing steadily since around 2012.
West African Forests
West Africa has already lost most of its original forests over the last century.
- Countries like Côte d’Ivoire and Ghana have lost more than 80% of their natural forest cover since the 1900s.
- Cocoa farming and other export crops have further accelerated recent deforestation.
Although biomass densities are generally lower than in the Congo, the aggregate emissions are comparable to the annual output of millions of vehicles.
East African Montane Forests
Highland forests in East Africa, such as Kenya’s Mau Forest complex, face different but equally severe pressures.
- From 2003 to 2022, about 18% of these montane forests disappeared.
- Their loss has contributed to faster local warming rates, roughly twice what would be expected from climate change alone.
- Higher cloud bases and reduced cloud cover have led to declining water availability for communities downstream.
These areas are also biodiversity hotspots, and their degradation threatens species like mountain gorillas that depend on intact forest habitats.
Savannas and Woodlands
Savannas present a more complex picture.
- In some regions of southern Africa, woody encroachment has increased biomass by roughly 0.12 petagrams per year during certain periods.
- Elevated CO2 levels can act like a fertilizer for shrubs and trees, allowing woody plants to spread into grasslands.
However:
- Around 17% of wooded savanna areas show signs of degradation.
- This degradation can release up to 55% of stored biomass carbon through thinning and recurrent fires.
Southern woodlands across countries like Zambia and Angola display mixed outcomes:
- Remote areas have seen biomass stocks rise by about 1–1.5%.
- Heavily populated areas, such as parts of Mozambique, have experienced net losses of roughly 3.4%.
Satellite images show a striking pattern: clearcuts clustered near settlements in the DRC and zones of regrowth in more isolated areas or managed plantations. Altogether, the continent looks like a patchwork where some regions are recovering while the wider trend still points toward increasing emissions.
Governance plays a decisive role. Stronger protections and better enforcement in countries like Gabon have helped safeguard forest gains, whereas conflict and instability in parts of the Sahel have intensified losses. This mosaic highlights where well-targeted interventions could have the greatest impact.
Global Climate Effects of the Shift
Africa’s forests used to help offset global emissions by absorbing carbon linked to deforestation elsewhere. Today, that balance has flipped.
- Historically, African ecosystems offset about 20% of global deforestation emissions.
- They now contribute roughly 200 million tons of CO2 each year due to biomass loss.
This added burden widens the global emissions gap and complicates efforts to achieve the Paris Agreement targets. Without Africa’s forests functioning as strong carbon sinks, other sectors and regions must undertake deeper and faster emissions cuts to keep warming well below 2°C.
The Congo Basin alone once absorbed around 600 million tons of CO2 per year. Now, as this capacity weakens, its role as a protective buffer against fossil fuel emissions is shrinking. Under those forests lie extensive peatlands that store an estimated 30 billion tons of ancient carbon. If drained or disturbed by deforestation, these peatlands could release massive additional emissions, creating a powerful feedback loop.
The consequences stretch far beyond Africa:
- More frequent and intense heat waves
- Disrupted rainfall patterns
- Rising sea levels threaten low‑lying and coastal communities worldwide
Within Africa, the impacts are already being felt.
- Rising temperatures and reduced rainfall are worsening droughts, putting the food security of roughly 1.4 billion people at risk.
- Loss of forests is undermining biodiversity and degrading water sources that supply millions of people.
- Economic sectors such as timber, tourism, and smallholder agriculture are becoming more vulnerable.
- Changing habitats can also increase the risk of disease transmission as wildlife and human populations are pushed into closer contact.
Savanna biomass gains offer a small ray of hope. If CO2‑driven woody encroachment continues and deforestation is curbed, these systems could recover some of the lost carbon storage. Still, the overall lesson is clear: global climate goals become much harder to reach if major forest regions continue to weaken as carbon sinks.
Expert Responses and Policy Actions
Scientists and climate experts have reacted with concern and urgency. Many describe the shift of Africa’s forests from sink to source as a critical warning for climate policy. The data has prompted several key messages:
- If African forests are no longer reliably absorbing carbon, other regions must cut their emissions even more deeply.
- Robust and ambitious Nationally Determined Contributions under the Paris Agreement are now even more important.
Technical assessments such as those from RECCAP (the Regional Carbon Cycle Assessment and Processes project) now classify Africa’s land carbon budget as a net source rather than a net sink, matching what biomass data indicate. Experts from organizations like CIFOR-ICRAF emphasize governance and transparency, arguing that better monitoring using satellite systems can help spot and reduce illegal logging.
Several policy initiatives are directly connected to this challenge:
- The Glasgow Leaders’ Declaration on Forests and Land Use aims for net‑zero deforestation by 2030.
- REDD+ (Reducing Emissions from Deforestation and Forest Degradation) offers financial incentives to conserve forests, although implementation remains uneven.
- AFR100 (the African Forest Landscape Restoration Initiative) has set a goal to restore 100 million hectares of degraded land by 2030, combining climate benefits with local job creation.
Despite these efforts, obstacles remain.
- Persistent funding gaps limit the scale of restoration and protection projects.
- Corruption and weak institutions can undermine forest governance.
- Conflicts and political instability complicate enforcement in several countries.
Even with some uncertainties in the data, especially in areas of very high biomass, researchers agree that delaying action will only strengthen Africa’s role as a net carbon source. The challenge now is translating detailed scientific maps and models into concrete policies, enforcement mechanisms, and on‑the‑ground change.
Pathways to Restoration and the Road Ahead
Restoring Africa’s forests is difficult but far from impossible. Multiple strategies are already under discussion or in motion:
- International finance facilities, such as proposals under “Tropical Forests Forever,” aim to direct long‑term funding toward countries that keep forests standing.
- Protected areas in parts of the Congo Basin have already helped stabilize biomass in certain regions, suggesting expansion and better management of these zones could gradually restore carbon sink functions.
Community‑based approaches are also central to any long‑term solution.
- Training local communities in sustainable harvesting practices can reduce dependence on destructive charcoal production.
- Agroforestry systems, which integrate trees into croplands and grazing areas, can boost food production and carbon storage simultaneously.
- Real‑time satellite alert systems can detect illegal logging early and support faster enforcement responses.
Looking forward, models suggest that if current trends persist, forest losses could grow significantly by 2050, pushed by population growth and rising demand for commodities, including from markets outside Africa. At the same time, there are possible counterweights:
- Continued CO2 fertilization may encourage woody plant growth in some savanna regions.
- Expanding climate finance and carbon markets could make conservation and restoration more economically attractive.
The outlook is one of cautious hope, dependent on how quickly and effectively policies, finance, and local actions align. Restoring and protecting Africa’s forests would:
- Help stabilize regional climates and reduce extreme heat
- Safeguard water sources for downstream communities
- Support wildlife and biodiversity that are globally important
Africa’s forests have moved from being powerful allies in the climate battle to becoming net contributors to the problem. Whether they can be returned to their former role as a major carbon sink will depend on choices made in the coming years, choices that will shape not only Africa’s future but the planet’s as well.
