TITLE:
Biochar Systems for Climate Change Mitigation and Soil Restoration in Sub-Saharan Africa: A Comprehensive Systematic Review
AUTHORS:
Maryanne M. Kinaro, Edwin Madivoli, Benson Karanja, Fredrick I. Njuguna, John Kiiru
KEYWORDS:
Biochar, Climate Change Mitigation, Soil Ammendments, Greenhouse Gas Reduction, Agricultural Residues, Sub-Saharan Africa, Circular Bioeconomy
JOURNAL NAME:
Open Access Library Journal,
Vol.13 No.8,
August
10,
2026
ABSTRACT: This systematic review assesses the policy implications of advancing biochar systems for climate mitigation, soil restoration, and climate-resilient agriculture in Sub-Saharan Africa (SSA), using Kenya as a focal case. Following PRISMA 2020 guidelines, it analyzes peer-reviewed literature from 2010-2025. Biochar derived from agricultural and forestry residues consistently improves soil structure, pH, water retention, and nutrient availability, with field-scale crop yield increases typically ranging from 10% - 40%. Benefits are most pronounced in degraded, acidic soils when biochar is combined with organic or inorganic fertilizers. It also reduces nitrous oxide and methane emissions through improved soil aeration and nitrogen retention, while stabilizing soil organic carbon, specifically, from high-temperature, lignin-rich feedstocks. Africa’s substantial biomass resource, exceeding 500 million tonnes of annual crop residues, presents significant technical potential. Case studies from Kenya, Nigeria, Ethiopia, South Africa, and the Sahel demonstrate agronomic, climate, and energy co-benefits within circular bioeconomy frameworks. However, scaling adoption faces pervasive challenges requiring targeted policy intervention. Technical constraints include rudimentary kilns and heterogeneous feedstocks producing inconsistent biochar quality. Institutional barriers involve weak Measurement, Reporting, and Verification (MRV) systems and fragmented policies failing to integrate biochar across agriculture, energy, waste, and climate sectors. Socioeconomic obstacles, such as high reactor costs, labor-intensive feedstock collection, limited credit access, and immature carbon markets, can further restrict smallholder uptake. Ethical concerns regarding residue competition, land-use change, and equitable benefit-sharing remain under-addressed in current governance frameworks. The SSA experience, exemplified by a number of countries including Kenya, encapsulates this duality: clear benefits for yields and mitigation contrast with the absence of long-term trials, national standards, and certified carbon methodologies. We conclude that unlocking biochar’s potential as a strategic pillar of climate-smart agriculture requires coherent policy action. Priorities include developing Africa-appropriate reactor technologies and quality standards; establishing robust, low-cost MRV frameworks to access carbon finance; enacting sustainable feedstock safeguards; and fostering inclusive, equity-sensitive governance. Ultimately, coordinated regional research networks and integrated policy alignment across sectors are essential to realize biochar’s environmental and socioeconomic benefits continent-wide.