Elevated atmospheric CO2: Impacts on crop growth, nutritional quality, and global food security

The rapid rise in atmospheric carbon dioxide (CO 2 ) levels, primarily driven by anthropogenic activities, significantly impacts global agricultural systems. Elevated CO 2 enhances photosynthesis, particularly in C 3 plants, leading to increased biomass production and potential yield improvements. However, this fertilization effect is often accompanied by a decline in essential nutrients, including proteins, iron, and zinc, in major food crops such as wheat and rice. This review explores the mechanisms underlying CO 2 -induced nutrient dilution, highlighting how carbohydrate accumulation, altered root physiology, and metabolic shifts contribute to reduced nutrient density. Empirical evidence from Free-Air CO 2 Enrichment (FACE) experiments and meta-analyses confirm that increased CO 2 concentrations lead to a consistent decline in crop nutritional quality, raising concerns about global food security and human health. Nutrient deficiencies resulting from CO 2 -driven dilution could exacerbate malnutrition, particularly in regions heavily reliant on staple crops for dietary sustenance. To mitigate these challenges, various strategies are discussed, including breeding nutrient-dense cultivars, optimizing soil management practices, and leveraging genetic modification technologies. Policy interventions promoting agricultural diversification and dietary adjustments are critical in addressing potential nutritional gaps. Future research should focus on long-term studies to assess the sustainability of CO 2 fertilization effects and interdisciplinary approaches integrating plant science, nutrition, and environmental policy. As atmospheric CO 2 levels continue to rise, proactive measures are essential to ensure both increased crop productivity and the maintenance of essential nutrient content for global nutritional security.