How a Major Senegal Mangrove Project Led to 'Ghost Carbon' Sales
A major mangrove restoration initiative in Senegal is facing criticism for overestimating carbon sequestration. With survival rates below 21% in many areas, the project sold credits for 'ghost carbon,' highlighting the urgent need for rigorous verification in the global carbon offset market.
Highlights
- •A large-scale mangrove restoration project in Senegal failed to meet its reforestation goals, with over 36% of plots showing zero survival.
- •Inaccurate carbon storage calculations overestimated sequestration, potentially misrepresenting 168,000 tonnes of CO2 as 'offset' emissions.
- •The project faced criticism for failing to adequately compensate local communities and for using land unsuitable for mangrove growth.
- •Experts warn that without better ecological monitoring, such initiatives risk selling 'ghost carbon' credits that do not deliver real climate benefits.
Nature-based solutions are increasingly central to global efforts against climate change, with mangroves serving as critical, high-efficiency natural carbon sinks. However, a significant reforestation initiative in Senegal has highlighted the potential risks of relying on these ecosystems to sell carbon credits. Recent investigations indicate that the project, intended to restore coastal forests, may have inadvertently generated what experts characterize as "ghost carbon."
Launched in 2008, the restoration project aimed to reforest over 10,000 hectares by involving local communities in planting millions of mangrove saplings. The overarching goal was to create a reliable blue carbon financing model, where the carbon sequestered by growing trees could be verified and sold as carbon credits to companies looking to offset their greenhouse gas emissions. Unfortunately, the actual outcomes have proven to be drastically different from the ambitious projections.
Evaluating the Failure of Mangrove Restoration
Research led by geographers and environmental scientists reveals that the project suffered from profound ecological design flaws. A staggering 36% of the planted plots experienced total failure, with no surviving mangrove vegetation. Furthermore, even in areas where some trees survived, the overall success rate was alarmingly low. It is estimated that only 18.3% to 20.5% of the total number of saplings planted across the project zone actually survived. Many trees were planted in unsuitable environments, such as high-salinity mudflats or areas located too far from tidal channels, preventing them from establishing the necessary root systems.
The financial and environmental implications of these failures are substantial. When the organization Verra approved the project's carbon credits, the verification process reportedly relied on calculations that assumed a significantly higher success rate and uniform growth across the entire 10,000-hectare site. By failing to account for the massive tree mortality, the project significantly overestimated the amount of carbon being sequestered.
Estimates suggest that the actual carbon storage was dramatically lower than what was reported to potential buyers. The discrepancy—totaling approximately 168,000 tonnes of carbon dioxide—could represent a financial value between $2 million and $7 million USD at current market prices. Beyond the environmental failure, social concerns have also emerged, with reports suggesting that only a small fraction of the promised $4.4 million in community payments was actually distributed, while local land access was restricted.
This situation serves as a warning for the global carbon market. As corporations rush to meet 2050 net-zero targets, the demand for nature-based offsets continues to rise. For these programs to maintain integrity, they must employ rigorous, independent ecological monitoring that accounts for actual survival rates. Without transparency, these projects risk trading "ghost carbon," undermining both environmental goals and public trust in vital climate initiatives.
