Free Green Carbon Webinar from 20th May 2021 by Elias Sebastian Azzi (KTH Stockholm, Sweden). In Sweden, biochar market development is mainly driven by use in urban applications like tree planting, green roofs, and landscaping soil. New applications for water treatment and concrete are also being developed. We had two research questions: i) what is the environmental performance of biochar products compared to current products? and, ii) how much biochar do we need in a city? We performed life cycle assessments and material flow analysis applied to the case of Uppsala, Sweden. Biochar products tend to perform better when they replace other problematic materials with high impacts, but environmental trade-offs also exists. This talk was presented as part of the Green Carbon Webinar Series.