Land-based climate solutions for the United States

G. Philip Robertson* (Corresponding Author), Stephen K. Hamilton, Keith Paustian, Pete Smith

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)
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Abstract

Meeting end-of-century global warming targets requires aggressive action on multiple fronts. Recent reports note the futility of addressing mitigation goals without fully engaging the agricultural sector, yet no available assessments combine both nature-based solutions (reforestation, grassland and wetland protection, and agricultural practice change) and cellulosic bioenergy for a single geographic region. Collectively, these solutions might offer a suite of climate, biodiversity, and other benefits greater than either alone. Nature-based solutions are largely constrained by the duration of carbon accrual in soils and forest biomass; each of these carbon pools will eventually saturate. Bioenergy solutions can last indefinitely but carry significant environmental risk if carelessly deployed. We detail a simplified scenario for the United States that illustrates the benefits of combining approaches. We assign a portion of non-forested former cropland to bioenergy sufficient to meet projected mid-century transportation needs, with the remainder assigned to nature-based solutions such as reforestation. Bottom-up mitigation potentials for the aggregate contributions of crop, grazing, forest, and bioenergy lands are assessed by including in a Monte Carlo model conservative ranges for cost-effective local mitigation capacities, together with ranges for (a) areal extents that avoid double counting and include realistic adoption rates and (b) the projected duration of different carbon sinks. The projected duration illustrates the net effect of eventually saturating soil carbon pools in the case of most strategies, and additionally saturating biomass carbon pools in the case of forest management. Results show a conservative end-of-century mitigation capacity of 110 (57–178) Gt CO2e for the U.S., ~50% higher than existing estimates that prioritize nature-based or bioenergy solutions separately. Further research is needed to shrink uncertainties, but there is sufficient confidence in the general magnitude and direction of a combined approach to plan for deployment now.

Original languageEnglish
Pages (from-to)4912-4919
Number of pages8
JournalGlobal Change Biology
Volume28
Issue number16
Early online date31 May 2022
DOIs
Publication statusPublished - Aug 2022

Bibliographical note

Funding Information:
We thank many colleagues for helpful discussion and feedback during the preparation of this analysis, anonymous reviewers for constructive criticism, and J.L. Schuette for help with data assembly. Financial support was provided by the U.S. Department of Energy Great Lakes Bioenergy Research Center (Award DE‐SC0018409), the U.S. National Science Foundation Long‐term Ecological Research Program (DEB 1832042), the USDA Long‐term Agroecosystem Research program, and Michigan State University AgBioResearch. Additional support (PS) is from the Soils‐R‐GGREAT (NE/P019455/1) and CIRCASA (Agreement 774378) projects of the European Union‘s Horizon 2020 Research and Innovation Programme (Award 774378); and (KP) the U.S. Department of Energy Advanced Research Projects Agency‐Energy program (Award DE‐AR0000826). KP serves as a part‐time advisor to Indigo Ag, Inc., a company that markets soil carbon sequestration credits. The authors declare no other potential conflicts of interest.

Publisher Copyright:
© 2022 The Authors. Global Change Biology published by John Wiley & Sons Ltd.

Data Availability Statement

All data in supplementary materials are available in Dryad (https://doi.org/10.5061/dryad.ghx3ffbr1).

Additional supporting information may be found in the online version of the article at the publisher’s website

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