text: **Yield change of maize in main countries.**There are huge differences in impacts on maize yield under 
  climate change, which would influence the food crisis in different regions. There are 159 countries in the whole 
  world which plant maize. The gross yield of maize the top 20 countries accounts for more than 90% of the total 
  yield in the 159 countries. So, the changes in the top 20 countries under future scenarios would influence the 
  food security of the whole world (Fig. 5). From the results of simulated by CRESE-maize under global warming 
  by 1.5 °C, there would be 75 countries facing with yield loss of maize; the mean yield loss rate would become 
  33.5%. There would be 84 countries experiencing yield increases. Overall, the global maize yield would slightly 
  increase. Under global warming by 2.0 °C, there would be 82 countries facing with yield loss of maize, for which 
  the mean yield loss rate is approximate to that under global warming by 1.5 °C. There would be 77 countries 
  experiencing yield increase; however, the mean yield increase is apparently smaller than that under global warm- 
  ing by 1.5 °C. Generally, the global maize yield would decrease. The results show that the adverse effect of warm- 
  ing up 2.0 °C on global maize production is far greater than warming up 1.5 °C. It is important to take actions to 
  develop forward-looking adaptation measures to cope with future climate change. 