The domestic and international implications of future climate for U.S. agriculture in GCAM

RESEARCH ARTICLE The domestic and international implications of future climate for U.S. agriculture in GCAM Abigail SnyderID1*, Katherine Calvin1, Leon Clarke2, James Edmonds1, Page Kyle1, Kanishka Narayan1, Alan Di Vittorio3, Stephanie Waldhoff1, Marshall Wise1, Pralit Patel1 1 Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park, MD, United States of America, 2 Center for Global Sustainability, University of Maryland, College Park, MD, United States of America, 3 Lawrence Berkeley National Laboratory, Berkley, CA, United States of America * abigail.snyder@pnnl.gov Abstract Agricultural crop yields are susceptible to changes in future temperature, precipitation, and other Earth system factors. Future changes to these physical Earth system attributes and their effects on agricultural crop yields are highly uncertain. United States agricultural pro- ducers will be affected by such changes whether they occur domestically or internationally through international commodity markets. Here we present a replication study of previous investigations (with different models) showing that potential direct domestic climate effects on crop yields in the U.S. have financial consequences for U.S. producers on the same order of magnitude but opposite in sign to indirect financial impacts on U.S. producers from climate effects on crop yields elsewhere in the world. We conclude that the analysis of coun- try-specific financial climate impacts cannot ignore indirect effects arising through interna-

tional markets. We find our results to be robust across a wide range of potential future crop yield impacts analyzed in the multi-sector dynamic global model GCAM. 1 Introduction Research is increasingly showing that agricultural crop yields will be susceptible to future changes in temperature, precipitation, length of growing seasons, and carbon dioxide (CO2) concentrations [1–9]. While future climate is uncertain, the potential for important effects on major agricultural crop producers such as the U.S. is clear [4, 8, 10–14]. The quantity and com- position of U.S. agricultural crop production, where crops are grown, trade, and economic value of U.S. crop production could be affected. An important challenge in understanding these implications is that agricultural products are traded across the globe. The U.S. is both a major agricultural importer and exporter of agri- cultural crops, meaning that U.S. agriculture may be affected not only by future climate in the U.S., but also future climate outside of the U.S. via international trade. These international linkages raise questions about the relative importance of the direct and indirect effects on U.S. agriculture; that is, is the potential for changes in temperature and precipitation in the U.S. (referred to here as domestic effects) more or less important than the potential for changes out- side of the U.S. (referred to here as international effects) to U.S. agricultural crop producers? PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0237918 August 28, 2020 1 / 11 a1111111111 a1111111111 a1111111111 a1111111111

a1111111111 OPEN ACCESS Citation: Snyder A, Calvin K, Clarke L, Edmonds J, Kyle P, Narayan K, et al. (2020) The domestic and international implications of future climate for U.S. agriculture in GCAM. PLoS ONE 15(8): e0237918. https://doi.org/10.1371/journal.pone.0237918 Editor: Alejandro Raul Hernandez Montoya, Universidad Veracruzana, MEXICO Received: January 31, 2020 Accepted: August 5, 2020 Published: August 28, 2020 Copyright: © 2020 Snyder et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: GCAM is publicly available at: https://github.com/JGCRI/gcam-core. Full model documentation is available at: http:// jgcri.github.io/gcam-doc/. The output data from these GCAM runs and code for figure production are attached as Supplement Information. The scenario files used for executing these GCAM runs are available on zenodo with a permanent DOI: 10.5281/zenodo.3979379 (https://doi.org/10.5281/ zenodo.3979379). Funding: This research was supported by the U.S. Department of Energy, Office of Science, as part of