How a 1.8-million-credit offtake agreement between a London-based reforestation startup and the world's largest carbon buyer is turning West Africa into a battleground for high-integrity climate finance.
In February 2026, a four-year-old company based in London signed the kind of deal that most forest restoration startups only dream about. Rainforest Builder - a fully integrated tropical reforestation firm with operations across Sierra Leone, Ghana, and Guinea - announced it had secured a 15-year offtake agreement with Microsoft to deliver up to 1.8 million carbon removal credits from a single project in Sierra Leone. One deal. One project. One of the largest carbon removal transactions ever struck on the African continent. It was not merely a commercial milestone. It was a signal that global capital markets are beginning to take West Africa's carbon potential seriously - and that the stakes of getting it right have never been higher.
Project Buffalo, Rainforest Builder's large-scale ecosystem restoration initiative in Sierra Leone, is the engine behind the Microsoft agreement. The project is targeting the restoration of 15,000 hectares of degraded community land, with a long-term goal of planting more than 10 million trees across the Upper Guinean Forest - a region scientists have designated one of the most biodiverse and most threatened forest ecosystems on the planet. Since breaking ground in 2023, the Sierra Leonean team has already planted more than 1.8 million trees. The Microsoft deal provides the long-term revenue certainty needed to push far beyond that.
The 15-year structure of the agreement is deliberately engineered. Long-term offtake deals are, in effect, financing instruments - they allow project developers to raise capital, hire local workforces, and build monitoring infrastructure by converting future credit revenues into present-day financial credibility. In 2025 alone, Project Buffalo directly employed 1,200 people in rural Sierra Leone, with employment expected to grow significantly as planting scales toward the 10-million-tree target. The project also anchors a broad community benefit-sharing framework: support for smallholder agricultural improvement, local road infrastructure investment, community land leasing arrangements, and a dedicated community development fund.
Edward Stephenson, co-CEO of Rainforest Builder, was direct about what this moment means for the continent. West Africa, he said, has experienced extreme levels of forest degradation but has been slower than other regions to attract the focus of global carbon markets. The Microsoft agreement, in his view, is a catalyst - not just for Rainforest Builder, but for the role that Africa, and Sierra Leone specifically, can play in those markets.
The Upper Guinean Forest is one of the most consequential ecosystems in the natural world - and one of the most damaged. Stretching from Sierra Leone and Guinea in the west across Liberia, Cote d'Ivoire, Ghana, and into Togo, the forest belt once covered tens of millions of acres of West Africa's Atlantic coast. It is home to an extraordinary concentration of biodiversity: more than 9,000 species of vascular plants, including 1,800 endemic species found nowhere else on earth. It supports 416 mammal species, 917 bird species, and remarkable numbers of amphibians and reptiles. According to conservation biologists, it contains the greatest number of mammal species of any of the world's designated biodiversity hotspots.
It also contains less than 10% of its original forest. Large-scale commercial logging began in some countries as early as the 1840s. Decades of agricultural expansion, slash-and-burn farming, diamond and gold mining, civil conflict, and the resulting collapse of environmental governance institutions combined to strip the region of nearly all its original tree cover. In Sierra Leone specifically, forest cover fell from roughly 70% to around 6% - a transformation that took less than two centuries. Many of the region's endemic and threatened species now survive in tiny fragments of old-growth forest that together cover less than 1% of Sierra Leone's land area.
Project Buffalo is directly targeting that collapse. Through rigorous site-species matching trials conducted under the oversight of Rainforest Builder's Scientific Advisory Board, the team has developed nursery operations that produce a variety of native tree species suited to each microenvironment across the project site. The company's proprietary data platform, called Chameleon, tracks operational and ecological data across all its projects in near real-time, enabling the kind of adaptive management that external verifiers and sophisticated corporate buyers now demand.
To understand why the Rainforest Builder deal matters beyond its immediate geography, you have to understand just how aggressively Microsoft has committed to carbon removal. The company announced in 2020 that it would become carbon negative by 2030 - not just carbon neutral, but actively removing more carbon from the atmosphere than it emits. By 2050, the stated goal is to have removed the equivalent of all the carbon Microsoft has ever emitted since its founding in 1975.
To reach those targets, Microsoft has turned itself into the largest single corporate purchaser of carbon removal credits in the world - by a significant margin. In fiscal year 2024, the company signed long-term agreements covering nearly 22 million metric tonnes of carbon removal, more than all previous years combined. In calendar year 2025, it more than doubled that figure, announcing agreements covering 45 million metric tonnes in a single year. The company has been expanding its portfolio across a remarkable range of technologies and geographies - from direct air capture facilities in Iceland and Norway to soil carbon projects for American farmers to bioenergy with carbon capture operations in Sweden. The Rainforest Builder agreement extends that reach into West African tropical restoration.
Phillip Goodman, director of carbon removal at Microsoft, described the rationale plainly: Project Buffalo is grounded in scientific rigor and supporting local communities, two priorities that Microsoft applies across its entire carbon removal portfolio. That framing is deliberate. After years of reputational damage inflicted on the voluntary carbon market by revelations of overestimated credits and poorly governed forest projects, the world's largest buyers have become considerably more sophisticated about what they will accept. Microsoft's internal criteria for high-quality carbon dioxide removal are publicly documented, regularly updated, and explicitly prioritize additionality, permanence, robust monitoring, and genuine community benefit.
The deal arrives at a complicated moment for Africa's voluntary carbon markets. On one hand, enthusiasm is at a historic high. The Africa Carbon Markets Initiative, backed by African Development Bank leadership and a coalition of international buyers, has set targets to generate 300 million credits annually by 2030 and unlock $6 billion in annual revenue. Demand for African credits, according to the ACMI's latest outlook data, rose by 11% even as global carbon credit demand fell by 22% - a striking divergence that points to growing confidence in the continent's high-quality supply.
On the other hand, the credibility damage inflicted by a wave of poorly governed projects over the past decade is not fully repaired. Revelations that some prominent REDD+ and avoided deforestation projects had significantly overstated their carbon sequestration led buyers to pull back sharply in 2022 and 2023, driving voluntary credit prices in some categories down toward $3 per tonne - well below the levels needed to sustain serious long-term restoration. Critics, including researchers and multilateral institutions, have also raised structural concerns about whether revenues from African carbon projects flow primarily to foreign developers, investors, and intermediaries rather than to local communities.
These are the dynamics that make Rainforest Builder's model worth watching closely. The company was founded in 2022 and spent its first years building operational capacity - nurseries, local hiring pipelines, scientific trial infrastructure - before arriving at the commercial scale that attracted Microsoft. Its Series A financing round, closed in March 2026 and led by BNP Paribas Asset Management Alts with participation from existing investors including Lansdowne Partners, was described as one of the largest private investments in a single forest restoration project to date. The BNPP AM Alts investment was structured through its Natural Capital and Impact strategy, and simultaneously unlocked financing for Project Colobus, the company's 24,000-hectare restoration project in eastern Ghana's Oti Region.
Alexandre Martin-Min, head of natural capital and impact investments at BNP Paribas Asset Management Alts, identified the combination of operational expertise and community integration as the deciding factor. West Africa, he said, has significant opportunity for natural climate solutions but has been underfunded. The team's depth in the region - and its approach to balancing ecological restoration with economic development - was what distinguished Rainforest Builder from less rigorous alternatives.
For Sierra Leone, a country that ranks among the world's least developed economies, the implications of deals like Project Buffalo extend well beyond carbon accounting. The country contributes negligible quantities of global greenhouse gas emissions - Africa as a whole accounts for just under 4% of global CO2 despite being home to 17% of the world's population - yet faces some of the most severe projected climate impacts, including intensifying drought, coastal erosion, and disruption to subsistence agriculture.
Carbon finance of the kind Rainforest Builder is channeling into the country represents a genuine revenue transfer mechanism: wealthy corporate emitters paying for ecosystem services that African communities and forests provide. But the distribution of that value within Sierra Leone matters enormously. Community land leasing payments, the community development fund, agricultural improvement programs, and direct employment in restoration operations are all design elements that determine whether a project genuinely transforms rural livelihoods or simply passes value upward to international capital.
The 15-year term of the Microsoft agreement is a significant structural safeguard. Projects with short revenue windows face obvious pressure to cut corners on monitoring, community engagement, and long-term planting survival. Projects with secured revenues over a decade and a half can afford the infrastructure and patience that real ecological restoration requires. As Rainforest Builder scales toward its long-term ambition of restoring one million hectares across West Africa by 2040 - across its four active projects currently targeting at least 370,000 hectares - the durability of that commercial foundation will determine whether the company's science-led model can survive at scale.
The Microsoft-Rainforest Builder deal represents a particular thesis about the near-term future of carbon markets: that high-integrity, restoration-focused, community-embedded projects in under-served African ecosystems can attract institutional capital at scale. It is a thesis being tested simultaneously across several fronts - by Rainforest Builder's own expansion into Ghana and Guinea, by the institutional validation of the BNPP AM Alts Series A, and by Microsoft's continued public commitment to becoming carbon negative by 2030 even a…