Biochar in circular economy and sustainable development: addressing technical variability, policy gaps, and sustainability constraints

Biochar exhibits multiple functions and has a long history of application. Its potential for carbon sequestration, soil remediation, and high-value waste disposal has also been extensively demonstrated. However, mainstream research often overstates biochar scalability prospects and pays insufficient attention to structural uncertainty and social ecological trade-offs, resulting in the underutilization of this technology in circular economy and sustainable development strategies. These unresolved challenges, including feedstock heterogeneity, ambiguous life-cycle performance, insufficient policy integration, and misaligned economic signals, collectively hinder its large-scale deployment. This commentary critiques the dominant techno-optimist narratives and brings attention to systemic barriers, particularly technical variability and regulatory incoherence. An integrative approach is advocated that couples spatially resolved techno-economic and life cycle assessments with coherent governance mechanisms. By repositioning biochar as a systems-level intervention, operating across interconnected domains of resource recovery, climate mitigation, and agro-ecological transformation, a more pragmatic roadmap for its deployment within circular economy frameworks is proposed. Scenario-based modeling and spatial risk integration are advanced as tools to contextualize trade-offs and operational constraints, thereby enabling a more grounded and policy-relevant discourse.