This review paper aims to synthesize the current state of carbon- negative innovations, with a focused analysis on biochar and hempcrete as paradigm materials, to assess their sequestration mechanisms, applications, and potential for mitigating climate change. Key quantitative findings from the assessed literature reveal that biochar, when incorporated at 50-70 wt.% in particleboard, can achieve flexural strengths exceeding 5.5 MPa. At the same time, hempcrete demonstrates the capacity to sequester up to 38.4% of its initial manufacturing CO₂ emissions and provides thermal insulation with U-values as low as 0.27 W/(m²·K). Biochar-augmented concrete formulations show promise, sequestering approximately 59 kg of CO₂ per tonne. Other emerging materials, such as mycelium-based composites, exhibit compressive strengths up to 1.1 MPa and low thermal conductivity (0.05–0.07 W/m·K). Life cycle assessments consistently indicate the carbon-negative potential of these technologies, with systems like integrated biochar filtration achieving a net impact of -1.41 kg CO₂ e/m³. The major conclusion underscores that while these materials present viable pathways for significant carbon sequestration and sustainable development across construction, agriculture, and energy sectors, their widespread adoption is hindered by challenges related to production cost, scalability, and regulatory frameworks. Future progress hinges on targeted research, supportive policy, and industrial collaboration to integrate these solutions into mainstream applications for a carbon-neutral future.
Sharma et al. (Tue,) studied this question.