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

to the explained variability of each crop are shown in Fig 2. The suitability of each crop and its geographical range are influenced by different biophysical parameters. The rainfall factors combined (sum of all three rainfall-related factors) have a larger influence on the potential suitability for the four crops in Ghana compared to the influence of temperature-based factors. These rainfall factors explain up to 60% of explained variability of cassava, up to 59% the vari- ability of groundnuts, 66% for maize and 57% the variability of sorghum (Fig 2). The total sum of rainfall received between March and September is more important in determining the suitability of maize (25%), cassava (23% and sorghum (19%). The mean tem- perature was not identified as important for any crop, but the diurnal temperature range explains about a quarter of the suitability for sorghum (26%), which is the highest value for any single variable. Variation of rainfall was important for all crops in almost equal measure (12–16%), with more importance for maize. Soil organic carbon was important (>10% contri- bution) for maize and cassava. The contribution of rainfall sum for sowing months, growing season mean temperature and mean temperature between March and September to the suit- ability of the four crops was mostly minimal (Fig 2). 3.3 Projected climate change impacts on agronomic variables Projected changes in agronomically important variables are shown in Table 3. The results indi- cate an increase in rainfall in Ghana for the cropping period, the sowing month and the grow-

ing season. However, these increases in rainfall will be accompanied by increases in the CV of rainfall of 3% for both scenarios at national level. Less rainfall increases are projected for RCP8.5 compared to RCP2.6 except for rainfall amounts in the sowing months. There is GCM agreement in direction of change for rainfall CV for RCP8.5 and sum of rainfall for sowing months for RCP2.6 and fir all temperature variables, which all indicate warming (Table 3). As expected, higher warming is projected under RCP8.5 compared to RCP2.6 with a decreasing temperature range. Fig 2. Variable importance of each of the parameters used in determining the suitability for maize, sorghum, groundnut, and cassava in Ghana. https://doi.org/10.1371/journal.pone.0229881.g002 PLOS ONE Climate change and food crops suitability in Ghana PLOS ONE | https://doi.org/10.1371/journal.pone.0229881 June 29, 2020 8 / 21