Pathways for biochar carbon removal: A national foresight study

Biochar carbon removal (BCR), achieved by stabilizing biogenic carbon through biomass pyrolysis, is gaining attention as a potential climate mitigation strategy. Yet, its future remains uncertain due to evolving market and regulatory conditions, and existing research provides limited insight into how these uncertainties interact to shape alternative deployment pathways. Using Denmark as a national case, this study combines expert interviews, stakeholder ranking, and scenario modeling to map critical uncertainties and explore plausible future pathways. Seven uncertainty categories are identified, with four emerging as critical: subsidies, carbon prices, regulations concerning biochar's agricultural use, and biomass availability. Stakeholders highlighted carbon prices and agricultural regulations as particularly decisive, which were then used for scenario development. Our results suggest that pyrolysis is relevant across all futures, but its role and scale differ markedly. Depending on the interaction between carbon prices and regulatory action, BCR may i) evolve as a large-scale carbon removal pathway, ii) shift towards non-agricultural biochar uses, iii) be confined to niche environmental applications such as sewage sludge treatment, or iv) become viable only within narrow subsidy-defined limits. These findings challenge implicit assumptions that technological readiness and rising carbon prices alone will lead to widespread BCR deployment. We demonstrate how deployment hinges on stable economic incentives and clear, predictable regulations. We conclude with recommendations for enabling the climate and environmental benefits of BCR across different plausible futures.