Climate smart agriculture and global food-crop production

the gains in yields (Supplementary Table S8 in S1 File). Nevertheless, overall the changes in pro- duction are sufficient to have a sizable impact on world prices (see description of endogenous effects in Supplementary Discussion S9 in S1 File). Prices are still projected to increase but com- pared to BAU their growth is reduced by 8% (3–17%) for maize, by 11% (3–25%) for wheat, and by 27% (13–42%) for rice with Rule 1, and by 6% (2–11%) for maize, 8% (2–20%) for wheat and 26% (14–40%) for rice with Rule 2 (Supplementary Table S9 in S1 File). As a result, the popula- tion at risk of hunger decreases more than what is projected by the BAU scenario. The number of people at risk of hunger is reduced by an additional 34 million (10–69 million) by 2050 under Rule 1 and by 29 million (10–59 million) under Rule 2, with the largest improvements in Sub- Saharan Africa, East Asia and Pacific, and South Asia. Similarly, the number of undernourished children decreases by an additional 2 million under both Rules 1 and 2 (a range of 1–5 million with Rule 1 and 1–4 million with Rule 2) with most of the improvements in Sub-Saharan Africa and South Asia (Supplementary Table S10 with Supplementary Figs 6 and 7 in S1 File). 3.2 GHG emissions Global GHG emissions decrease under both adoption scenarios, but there are important dis- tinctions between the two. When farmers’ adoption choices are based only on yield increases Table 2. Summary of scenarios simulated. Scenarios Climate model CSA tailoring Socioeconomic & Emission assumptions Simulation BAU GFDL None SSP2 + RCP8.5 1

HadGEM None 2 Adoption Rule 1: Higher yields than BAU GFDL Lower 3 Average 4 Optimal 5 HadGEM Lower 6 Average 7 Optimal 8 Adoption Rule 2: Lower emissions intensity & higher yields than BAU GFDL Lower 9 Average 10 Optimal 11 HadGEM Lower 12 Average 13 Optimal 14 Adoption Rule 1 and rates of technology uptake from Rosegrant et al 2014 [9] GFDL Lower 15 Average 16 Optimal 17 HadGEM Lower 18 Average 19 Optimal 20 Adoption Rule 2 plus AWD production costs GFDL Lower 21 Average 22 Optimal 23 HadGEM Lower 24 Average 25 Optimal 26 Source: Authors https://doi.org/10.1371/journal.pone.0231764.t002 PLOS ONE Climate smart agriculture and global food-crop production PLOS ONE | https://doi.org/10.1371/journal.pone.0231764 April 29, 2020 8 / 19