Achieving net-zero greenhouse gas emissions is essential to meet global climate targets, and this objective cannot be realized without large scale deployment of carbon dioxide removal (CDR), especially for the pathways limiting warming to 1.5 °C or well below 2 °C. Biochar is part of the CDR portfolio that has a potential for a long-term carbon storage and the provision of environmental co-benefits that go beyond the carbon dioxide removal. Scaling up this technology requires an extensive understanding of many aspects including feedstock availability. Fundamental geological and industrial datasets required for spatially explicit analyses are often incomplete or imprecise, limiting the robustness of current assessments of CDR feedstock availability.