Carbon dioxide fertilization, carbon neutrality, and food security

Understanding how carbon dioxide (CO₂) fertilizes crop yields is crucial for assessing potential threats to food security in a changing climate, characterized by evolving atmospheric CO₂ concentrations. Utilizing an instrumental variable based on the long-distance transmission of CO₂ from upwind counties, we investigate the causal effects of CO₂ on crop yields. Our findings provide evidence that a one-standard-deviation increase in CO₂ leads to significant increases in rice, wheat, and corn yields, with effect sizes of 0.3066, 0.7313, and 0.1398 standard deviations, respectively. Moreover, our research provides evidence indicating that the carbon fertilization effects shape the agricultural landscape in China by influencing the acreage shifts across crops. Projecting future crop productions based on a scenario of carbon neutrality aligned with the Paris Agreement, we anticipate that total crop production in China will reach its peak in 2041, followed by a gradual decline. Temperatures will largely offset the predicted changes in crop output brought on by CO₂, and the predicted CO₂-induced crop production will change accordingly when taking acreage shifts into account.