Impacts of climate change on agro-climatic suitability of major food crops in Ghana

RESEARCH ARTICLE Impacts of climate change on agro-climatic suitability of major food crops in Ghana Abel ChemuraID*, Bernhard Schauberger, Christoph Gornott Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, Potsdam, Germany * chemura@pik-potsdam.de Abstract Climate change is projected to impact food production stability in many tropical countries through impacts on crop potential. However, without quantitative assessments of where, by how much and to what extent crop production is possible now and under future climatic con- ditions, efforts to design and implement adaptation strategies under Nationally Determined Contributions (NDCs) and National Action Plans (NAP) are unsystematic. In this study, we used extreme gradient boosting, a machine learning approach to model the current climatic suitability for maize, sorghum, cassava and groundnut in Ghana using yield data and agro- nomically important variables. We then used multi-model future climate projections for the 2050s and two greenhouse gas emissions scenarios (RCP 2.6 and RCP 8.5) to predict changes in the suitability range of these crops. We achieved a good model fit in determining suitability classes for all crops (AUC = 0.81–0.87). Precipitation-based factors are sug- gested as most important in determining crop suitability, though the importance is crop-spe- cific. Under projected climatic conditions, optimal suitability areas will decrease for all crops except for groundnuts under RCP8.5 (no change: 0%), with greatest losses for maize (12%

under RCP2.6 and 14% under RCP8.5). Under current climatic conditions, 18% of Ghana has optimal suitability for two crops, 2% for three crops with no area having optimal suitabil- ity for all the four crops. Under projected climatic conditions, areas with optimal suitability for two and three crops will decrease by 12% as areas having moderate and marginal condi- tions for multiple crops increase. We also found that although the distribution of multiple crop suitability is spatially distinct, cassava and groundnut will be more simultaneously suit- able for the south while groundnut and sorghum will be more suitable for the northern parts of Ghana under projected climatic conditions. 1. Introduction The agricultural sector of tropical countries is at great risk from the impacts of climate change. This is because of changes in weather patterns, which determine yields and crop production in these areas [1, 2]. Projections show that about a third of the world’s population will be living in these countries by 2050, and the impact on agriculture is regarded as the most important and immediate danger of climate change to society [3, 4]. In Ghana, agriculture employs more PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0229881 June 29, 2020 1 / 21 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Chemura A, Schauberger B, Gornott C (2020) Impacts of climate change on agro-climatic suitability of major food crops in Ghana. PLoS ONE 15(6): e0229881. https://doi.org/10.1371/journal. pone.0229881

Editor: Shahid Farooq, Harran University, TURKEY Received: February 17, 2020 Accepted: June 14, 2020 Published: June 29, 2020 Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: https://doi.org/10.1371/journal.pone.0229881 Copyright: © 2020 Chemura 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: Data used in the analysis is curated on Zenodo (https://zenodo.org/ record/3669955/) and publicly available (DOI: 10. 5281/zenodo.3669955). Funding: This work was funded by the German Ministry for Economic Cooperation and