Biochar for climate, circularity and carbon markets: technologies, integrity, deployment gaps and pathways to scale
Year: 2026
Type: article
Abstract: Biochar has moved from a soil-amendment niche to one of the most active durable carbon dioxide removals (CDR) pathways. Its apparent simplicity, thermochemical conversion of biomass under oxygen-limited conditions, can conceal a complex climate claim. A verified tonne of biochar removal requires sustainable and additional feedstock, controlled conversion, stable carbon characterisation, traceable long-term end use, lifecycle emission accounting and independent monitoring, reporting and verification (MRV). This review evaluates the state of the art in biochar technologies, quality enhancement, carbon-market methodologies, research gaps, market gaps, business constraints and implementation bottlenecks. It integrates recent peer-reviewed literature with current rules from Puro.earth and Verra, which now place stronger emphasis on durable storage, responsible biomass sourcing, additionality, environmental safeguards and auditable application routes. The review finds that higher pyrolysis severity can improve aromaticity and stability but may lower char yield and alter nutrient, energy and product economics; therefore, “higher temperature” is not a universal optimisation rule. Feedstock heterogeneity, moisture, logistics, process emissions and uncertainty in end-use fate are the main causes of divergence between gross char production and net credited removal. Biochar currently has a comparatively advanced carbon-removal market position. The paper proposes a Biochar Integrity and Deployment Framework that connects feedstock qualification, process control, product characterisation, end-use routing, digital chain of custody, lifecycle netting and post-issuance monitoring. The central conclusion is that high-integrity biochar is best understood as an integrated residue-management, materials, agriculture and carbon-accounting system rather than a standalone reactor business.
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7171983167