September 15-20, 2019
Carbon dioxide withdrawal from the atmosphere is increasingly seen as an indispensable approach to mitigate climate change in concert with emission reductions from fossil fuel use. Conversion of biomass into biochar decreases mineralizability by one to two orders of magnitude and typically constitutes half of life-cycle emission reductions of biochar systems focusing on crop or forestry residues. In addition, emission reductions related to changes in nitrous oxide emissions or photosynthesis may contribute to climate change mitigation. While impacts of pyrolyzing carbon-rich crop or forestry residues on greenhouse gas emissions have been widely investigated, less attention has been paid to nutrient-rich materials such as animal manures or human wastes. Nutrient recycling using pyrolysis not only reduces climate impacts by several tens of percent but also enables establishing new products in the market place and reducing environmental impacts beyond climate change. In comparison to other major carbon dioxide removal approaches such as crop management or restoration of wetlands, biochar systems may generate greater emission reductions at equivalent carbon dioxide removal. The reason may lie in a systemic reduction of soil-based emissions of non-carbon dioxide greenhouse gases and the greater control of the conversion process in what essentially is a hybrid engineered-biological sequestration. Due to biochar being an external carbon resource, it does typically not constitute an on-site competition for organic matter as observed with crop management and increasing carbon in soil with biochar may therefore not constitute a trade-off with food production. These features make biochar systems a complementary approach to other ways of reducing greenhouse gases with potentially large contributions to a global strategy to mitigate climate change.
Johannes Lehmann, "Biochar beyond carbon sequestration: Life-cycle emission reductions, nutrient recycling and food security" in "Bio-Char II: Production, Characterization and Applications", Franco Berruti, Western University, London, Ontario, Canada David Chiaramonti, RE-CORD, University of Firenze, Italy Ondrej Masek, University of Edinburgh, Edinburgh, United Kingdom Manuel Garcia-Perez, Washington State University, USA Eds, ECI Symposium Series, (2019). https://dc.engconfintl.org/biochar_ii/73