Operationalising net-zero with biochar: Black gold or red herring?

Nascent anecdotal evidence implies that livestock feed supplementation with biochar may reduce enteric methane, improve liveweight gains (LWG) and soil carbon through manure enrichment. However, the cost-effectiveness and potential adoption of biochar as animal feed remain unclear, especially when considering its connection to carbon markets and the social perception. Here, we dissect our hypothesis using an integrated, cross-disciplinary participatory modelling framework, grounded data from farm trials and insights from an expert group of industry practitioners. The farm trial shows that steers fed with biochar ad libitum increased LWG relative to unsupplemented controls (5% improvement after 14 months). The scenario analysis indicates that, at carbon prices of $25-75 Mg−1 CO2e and $2000 Mg−1 biochar, LWG would need to be at least 5% greater to be profitable. Based on perceived environmental benefits and ease of trialing, our industry adoption modelling shows a variable adoption rate of 10–69% over 5–7 years. The participatory approach with farmers revealed strengths (animal health co-benefits), weaknesses (costs), opportunities (carbon markets), and threats (antagonism with other feed additives) of biochar supplementation. Biochar as feed can increase LWG and soil organic carbon but its viability will depend on economies of scale, integration with carbon markets, and carbon credit prices.