Are Increasing Levels of CO2 Causing Hidden Hunger

Jun 25, 2014


According to a recent commentary “Food Security: Fertilizing hidden hunger” by Müller C. and others published in Nature Climate Change, CO2 fertilization and climate change will likely exacerbate macro and micro-nutrients deficiency in crops, jeopardizing one of the most important millennium development goals: to eradicate extreme poverty and hunger. This declining nutritional content could lead to “hidden hunger”– defined by the authors as an “insufficient supply of vitamins and minerals in diets with sufficient calorie content.”

The impacts of climate change on agriculture and food security are normally studied focusing on yields and calories. However, the authors claim that this scope may be misleading when analyzing the effect of CO2 fertilization. In a changing climate, increasing CO2 levels stimulate photosynthesis and plant growth (especially in essential crops like wheat, rice and soy), and reduce water consumption due to a more efficient use of nitrogen, compensating for some of the negative effects of climate change. However, Myers and others presented compelling evidence that higher levels of CO2 will also negatively affect the nutritional value of important food crops, reducing concentrations of essential minerals (like Iron and Zinc) and proteins. This threat to the nutritional value of crops could have important implications for health and nutrition and should definitely be considered in future food security assessments. 

Finally, the authors state two central challenges that need to be faced to improve understanding of risks related to the nutritional quality of food. First, the ambivalent effects of CO2 fertilization on food security need deeper analysis and should be represented in crop models. The authors mentioned that the Agricultural Model Intercomparison and Improvement Project (AgMIP) and the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP) are platforms that could help facilitate interactions between different disciplines (crop modelers, breeders, physiologists and human health researchers) that have to be involved to solve this challenge. Second, models will have to address hidden hunger in upcoming work and expand the scope of the models to include nutritional quality.