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Elevated CO2 Increases Minerals at the Base of Human Nutrition
Volume 17, Number 35: 27 August 2014

In a meta-analysis of 130 different species/cultivars of various agricultural plants, Loladze (2014) concludes that an atmospheric CO2 concentration increase on the order of 300 ppm tends to decrease the overall mineral concentrations of the edible portions of almost all agricultural plants by an average of 8%, exacerbating the prevalence of what he calls "hidden hunger." But does this small percentage reduction really intensify this latter malady?

In the case of the two main food crops Loladze mentions - rice (Oryza sativa) and wheat (Triticum aestivum) - it is important to also consider the increase in crop biomass production that is provided by a 300-ppm increase in the air's CO2 concentration, which is something that we have regularly tabulated on our website for the past several years whenever a new study of the subject has been published. And when we go there to see what has been learned about wheat in this regard, we find that the mean crop yield increase of 260 separate studies is 33.4%, while in the case of rice the mean yield increase of 224 different studies is 36.1%, or approximately 35% for the two crops together.

So if M represents the amount of minerals found in these plants when grown in ambient-CO2 air, the amount of minerals found in these plants when grown in air enriched with an extra 300 ppm of CO2 is 0.92M. But if the yields of the two crops per unit land area are approximately 35% greater, we multiply 0.92M by 1.35 to obtain a net increase in mineral mass of 1.24M or 24% from the same amount of cropland, which should greatly help to rid humanity of "hidden hunger."

Sherwood, Keith and Craig Idso

Loladze, I. 2014. Hidden shift of the ionome of plants exposed to elevated CO2 depletes minerals at the base of human nutrition. eLife 3: e02245.