We have written about the biological benefits of elevated temperatures and atmospheric CO2 levels hundreds of times, and we will never run out of new material! Evidence the results of two recent article showing how CO2 improves the yield of wheat and the competitiveness of rice.
A team of seven scientists from various agencies in China began their article noting "In the past 100 years, the mean surface temperature in China has increased by 0.4-0.6ºC, and it is expected that the average surface temperature in western China will rise by 1.7ºC in the next 30 years and by 2.2ºC over the next 50 years." Furthermore, Xiao et al. report "The annual mean rainfall decreased by about 60 mm [~2.4 in.] from the 1950s to the 1990s in semiarid regions of China, and a loss of soil moisture through evaporation increased 35-45 mm [~1.5 in.] due to the temperature increase. The rainfall and available soil moisture throughout the entire growing stage of the crops was about 100 mm [~4 in.] lower in the 1990s than in the 1950s. As a result, concerns about the vulnerability of agricultural production to climate change are increasing. For example, it is likely that evaporation will increase and soil moisture will decline in many regions as the temperature increases." If that is not enough bad news, they state "There is now strong evidence that overall crop yields will decrease by 5-10% in China by 2030 as a result of climatic changes, and that the yields of wheat, rice and maize will be greatly reduced."