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Research article - Peer-reviewed, 2023

Potential for biochar carbon sequestration from crop residues: A global spatially explicit assessment

Karan, Shivesh Kishore; Woolf, Dominic; Azzi, Elias Sebastian; Sundberg, Cecilia; Wood, Stephen A.

Abstract

Global warming necessitates urgent action to reduce carbon dioxide (CO2) emissions and remove CO2 from the atmosphere. Biochar, a type of carbonized biomass which can be produced from crop residues (CRs), offers a promising solution for carbon dioxide removal (CDR) when it is used to sequester photosynthetically fixed carbon that would otherwise have been returned to atmospheric CO2 through respiration or combustion. However, high-resolution spatially explicit maps of CR resources and their capacity for climate change mitigation through biochar production are currently lacking, with previous global studies relying on coarse (mostly country scale) aggregated statistics. By developing a comprehensive high spatial resolution global dataset of CR production, we show that, globally, CRs generate around 2.4 Pg C annually. If 100% of these residues were utilized, the maximum theoretical technical potential for biochar production from CRs amounts to 1.0 Pg C year(-1) (3.7 Pg CO(2)e year(-1)). The permanence of biochar differs across regions, with the fraction of initial carbon that remains after 100 years ranging from 60% in warm climates to nearly 100% in cryosols. Assuming that biochar is sequestered in soils close to point of production, approximately 0.72 Pg C year(-1) (2.6 Pg CO(2)e year(-1)) of the technical potential would remain sequestered after 100 years. However, when considering limitations on sustainable residue harvesting and competing livestock usage, the global biochar production potential decreases to 0.51 Pg C year(-1) (1.9 Pg CO(2)e year(-1)), with 0.36 Pg C year(-1) (1.3 Pg CO(2)e year(-1)) remaining sequestered after a century. Twelve countries have the technical potential to sequester over one fifth of their current emissions as biochar from CRs, with Bhutan (68%) and India (53%) having the largest ratios. The high-resolution maps of CR production and biochar sequestration potential provided here will provide valuable insights and support decision-making related to biochar production and investment in biochar production capacity.

Keywords

biochar; carbon sequestration; crop residues; geospatial information science; global maps; negative emissions

Published in

GCB Bioenergy
2023, Volume: 15, number: 12, pages: 1424-1436
Publisher: WILEY

    UKÄ Subject classification

    Bioremediation

    Publication identifier

    DOI: https://doi.org/10.1111/gcbb.13102

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/126788