Rising CO2 Zaps Crops of Nutrition

Grains and legumes shown to lose zinc, iron

May 8, 2014
Outside Magazine

Increased CO2 often means an increase in crops, but they might not be as good for you.    Neil Howard/Flickr

Climate change may have granted us a short-term gain in the length of our growing season, but as we learned on Tuesday, our food system might be in trouble over the long term. A new study adds to the list of concerns, finding that higher concentrations of carbon dioxide in the atmosphere can yield less-nutritious crops.

The study, published in Nature, found that increased CO2 levels during the growing process sapped as much as 15 percent of the zinc and iron from certain grasses and legumes. Seeing as how these two minerals alone are the two most abundant in the human body, that could pose a significant public health problem.

What's more, the crops discussed in this study include many of our old standbys: wheat, rice, barley, soybeans, and corn. Of course, there was some variability in how each plant responded to the increased CO2, which scientists matched to levels we might expect over the next four to six decades. Some kinds of rice actually became slightly more nutritious. We also know that more CO2 often means a higher crop yield.

However, the increased volume of crops likely didn't influence that drop in nutrients. The researchers said that there are unknown factors at play here, and they plan to get cracking on exactly what those are. It's just another step toward staving off malnutrition in our changing world.