Paper Reviewed
Hao, X., Gao, J., Han, X., Ma, Z., Merchant, A., Ju, H., Li, P., Yang, W., Gao, Z. and Lin, E. 2014. Effects of open-air elevated atmospheric CO2 concentration on yield quality of soybean (Glycine max (L.) Merr). Agriculture, Ecosystems and Environment 192: 80-84.

It's always nice to have a lot of something good, like the food that both mankind and the world's animals eat. And in this regard, it's also nice to know that atmospheric CO2 enrichment tends to increase the quantity of nearly all food crops known to man. But what about the quality of that food? Is it also increased? Or, as many of the world's climate alarmists like to suggest, is it reduced? The answer depends on one's perspective, as illustrated by the report of Hao et al. (2014), which was published in Agriculture, Ecosystems and Environment.

In a study by this group of ten scientists that was conducted at the China Mini-FACE (Free-Air CO2 Enrichment) site near Changping, Beijing, under normal field conditions in 2009 and 2011 as part of a wheat/soybean rotation, they found that an atmospheric CO2 enrichment of only 135 ppm increased the yields of soybean seeds by 26% and 31%, respectively, which correspond to yield increases on the order of 58% and 69% for the more-commonly-used CO2 enhancement value of 300 ppm.

Hao et al. additionally found that the concentrations of a number of beneficial oils in the soybean seeds were increased by an average of 2.8% in response to the 135-ppm increase in the air's CO2 concentration. However, they also discovered that the total protein concentration in the seeds was reduced by 3.3% in the CO2-enriched treatment. But because of the much greater CO2-induced increase in the soybean seed yields, or biomass production per unit of cultivated land, they report that the total "protein and oil yield per unit ground area increased by 24.5% and 32.0%, respectively."

In conclusion, therefore, and quoting Hao et al., "elevated CO2 levels may increase the total protein and oil production, potentially improving human nutrition and oil supply derived from soybean crops."