Carbon compensation or fuel displacement? Biomass allocation trade-offs for decarbonizing aviation

Waste biomass can deliver climate mitigation through two fundamentally different routes: durable carbon removal via biochar and fossil-jet displacement via sustainable aviation fuel (SAF). We harmonize published techno-economic assessments to a common 2024 delivered-to-market basis and compare both pathways as climate-service abatement cost (USD tCO 2 − 1 removed or avoided). For biochar, we combine an empirical cost-capacity relationship with audited net-removal factors. For SAF, we distinguish the commercially dominant waste-lipid route from the waste- and residue-derived pathways needed for larger long-run scale. Commercial biochar systems currently deliver a median abatement cost of about 177 USD tCO 2 − 1 (5th–95th percentile: 111–497 USD tCO 2 − 1 ), while waste-derived SAF centers near 448 USD tCO 2 − 1 . Current SAF supply is still overwhelmingly lipid-based, whereas the lignocellulosic and municipal-solid-waste routes needed for larger long-term aviation abatement remain earlier in commercialization. These differences suggest complementary timelines: biochar is a near-term removal option, while SAF remains a longer-term aviation decarbonization pathway.