The impact of rising carbon dioxide levels on crop nutrients and human health

Carbon dioxide (CO2) levels are rising globally at a rapid pace, on track to surpass 550 parts per million (ppm) by midcentury. Studies have found that, when grown under elevated CO2 concentrations of 546–586 ppm, many food crops—including wheat, rice, barley, and soybeans—have lowered concentrations of nutrients, including many that are important for overall health, such as iron, zinc, and protein. Elevated CO2 also affects both the quantity and quality of forage, thereby affecting animal performance and production and, consequently, the availability of nutrients from animal-source foods, such as meat, milk, and eggs. This loss of dietary nutrients in foods could translate to increased nutritional deficiency for hundreds of millions of people already on the brink of deficiency—mainly developing countries in Asia, the Middle East, and North Africa based on dietary preferences for the commodities most affected. This policy note examines the link between rising CO2 levels and declining nutritional content for a number of major crops, as well as forage. The discussion includes a comparison of the varying effects by crop, and strategies to address this challenge in the context of climate change.