Agriculture, bioenergy, and water implications of constrained cereal trade and climate change impacts

in domestic consumption of cereals and hence a decrease in domestic consumption of non- cereals. Second, as importing regions are forced to increase imports of non-cereal crops dis- placing cereal imports, exporting regions increase their non-cereal crop export. As a result, the combined effect on non-cereal production is small. The effects of this constraint on non-cereal crops are observed in the Middle East, which increases production, consumption, and imports of non-cereal crops, to offset the 5% decrease in consumption of cereals in ID. In CC, the USA generally decreases non-cereal crop production, exports, and imports. However, consumption of non-cereal crops increases, partially offsetting the decrease in cereal consumption. In the Middle East, yields for non-cereal crops generally increase in CC, leading to an increase in production and consumption and a decrease in imports. In IC, the effects of trade perturbations dominate in the Middle East with production, con- sumption, and trade changes for non-cereals resembling those in ID. In the USA, however, the CC impacts are slightly stronger than ID in these outcomes for non-cereal crops. Table 2. Summary of key variable results in 2050 for the Middle East. The numbers in the parentheses indicate the percent change compared to RF. Numbers are rounded. Mt—Million tons. Key Variable of RF ID CC IC Import dependency ratio Cereals 64% 0% 63% 0% Production (Mt) Cereals 52 72 (38.3%) 52 (0.1%) 72 (38.5%) Non-Cereals 147 169 (15.1%) 151 (3.1%) 174 (18.7%) All Crops 198 240 (21.1%) 203 (2.3%) 246 (23.8%)

Consumption (Mt) Cereals 142 72 (-49.6%) 140 (-1.2%) 72 (-49.5%) Non-Cereals 197 252 (27.4%) 199 (1.2%) 255 (28.9%) All Crops 339 323 (-4.6%) 339 (0.2%) 326 (-3.7%) Exports (Mt) Cereals 0.7 19.4 (2599.0%) 0.8 (6.2%) 19.7 (2640.3%) Non-Cereals 5.3 4.3 (-18.6%) 5.6 (6.0%) 4.5 (-15.0%) All Crops 6.0 23.7 (294.7%) 6.4 (6.0%) 24.2 (302.8%) Imports (Mt) Cereals 90.8 19.4 (-78.6%) 89.1 (-1.9%) 19.7 (-78.3%) Non-Cereals 55.4 87.0 (57.0%) 53.6 (-3.2%) 84.8 (53.2%) All Crops 146.2 106.4 (-27.2%) 142.7 (-2.4%) 104.6 (-28.5%) Net Trade Revenue (billion 2015$) Cereals -25.6 -1.4 (-94.5%) -25.5 (-0.4%) -1.5 (-94.3%) Non-Cereals -15.0 -22.3 (49.0%) -15.3 (2.4%) -22.9 (53.1%) All Crops -40.6 -23.7 (-41.6%) -40.8 (0.6%) -24.4 (-40.0%) Crop producers’ Revenue (billion 2015$) Cereals 26 44 (71.9%) 26 (0.5%) 45 (73.3%) Non-Cereals 118 133 (12.6%) 122 (3.7%) 138 (16.8%) All Crops 144 177 (23.2%) 148 (3.1%) 183 (27.0%) Caloric Consumption (Kcal/cap/day) Cereals 1182 1078 (-8.7%) 1181 (0.0%) 1076 (-8.9%) Non-Cereals 1477 1585 (7.3%) 1473 (-0.3%) 1582 (7.2%) Staples* 1230 1230 (0.0%) 1230 (0.0%) 1230 (0.0%) All Food 2659 2663 (0.2%) 2654 (-0.2%) 2659 (0.0%) Food Expenditures as a share of GDP All Food 0.82% 0.85% 0.84% 0.88% Irrigation Water Consumption (km3) Cereals 62.3 86.8 (39.3%) 61.6 (-1.1%) 86.1 (38.2%) Non-Cereals 99.9 109.5 (9.6%) 101.8 (1.9%) 111.7 (11.8%) All Crops 162.2 196.3 (21.0%) 163.4 (0.7%) 197.8 (22.0%)

Ethanol Production (EJ) Corn 0.181 0.007 (-96.0%) 0.156 (-13.8%) 0.006 (-96.8%) Corn Consumption for Ethanol (Mt) 20 0.8 (-96.0%) 17.4 (-13.8%) 0.6 (-96.8%) Share of Corn Consumption for Ethanol 55.2% 14.1% 54.1% 12.1% *Staples include cereals as well as roots and tubers in our model. https://doi.org/10.1371/journal.pone.0291577.t002 PLOS ONE Agriculture, bioenergy, and water implications of constrained cereal trade and climate change impacts PLOS ONE | https://doi.org/10.1371/journal.pone.0291577 September 15, 2023 12 / 18