Nutritional quality of crops in a high CO2world: An agenda for research and technology development

Abstract

Essential nutrients, including carbohydrates, proteins, fats, vitamins, and minerals, are required for human health and development. Inadequate intake can negatively affect development and result in a wide range of adverse health outcomes. Rice, maize, and wheat provide over 60% of the world's food energy intake. Atmospheric carbon dioxide (CO2), water, nitrogen, and soil micronutrients are the basis of this plant material. Since 1850-1900, CO2 concentrations have increased about 50%, with most of that increase since 1950. Higher CO2 concentrations increase photosynthesis, which then increases plant biomass, but also alters the nutritional quality of wheat, rice, and other C3 plants. We review the possible impacts of rising CO2 concentrations on human health, highlight uncertainties, and propose a research agenda to maintain the nutritional quality of C3 plants. We also synthesize options for addressing this critical challenge to nutritional safety and security. A complete research agenda requires addressing data and knowledge gaps surrounding plant biology and policy responses. Data on key nutrients are lacking, leading to a limited mechanistic understanding of the response of the plant ionome to elevated CO2 concentrations. Regular data are largely missing on nutritional status and food safety in low- and middle-income countries, limiting assessments of the magnitude of the risks. Research opportunities to fill gaps in data and understanding include herbaria studies, field-based natural and manipulative studies, leveraging natural plant variability, and innovations in seed quality. Improved models of cereal crop nutritional quality can project the magnitude and direction of possible future challenges; incorporating the effects of climate change into those models can further improve their robustness. Transdisciplinary research involving at least ecologists, plant physiologists, economists, and experts in human nutrition is essential for developing a systems-based understanding of the potential impacts of rising CO2 concentrations for human nutrition and the attendant consequences for achieving the sustainable development goal on food security.