Food crops will take a hit as atmospheric carbon dioxide levels rise

Scientists have wondered what more carbon dioxide in the atmosphere will mean for food crops, and a new report answering that question has experts worried.

In a new study published in Nature, researchers shared findings from recent experiments on crops conducted around the world. NPR reports that scientists put carbon dioxide jets in open fields, releasing 500 parts per million of C02, the amount estimated to be in the air in 40 to 60 years (currently, carbon dioxide reaches roughly 400 parts per million). Researchers grew rice, wheat, and peas, and discovered that while crops grew faster and had yields increase by 10 percent, there was also a 5-10 percent reduction in nutrients like protein, zinc, and iron.

"If elevated CO2 or other climate change processes are working against us, we're going to have to work even harder to raise those levels," Michael Grusak, a researcher with the USDA's Children's Nutrition Research Center, told NPR. Scientists are not sure why this happens, but believe it could be that as plants produce more food, trace nutrients become diluted.

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Zinc and iron deficiencies are already affecting two billion people around the world, with serious consequences: A lack of zinc prevents a child's immune system from working properly, and insufficient iron intake lowers the IQ of children, NPR says. As it is, many of the most popular crops in the world, particularly rice and corn, already don't have much iron or zinc; they are staples mainly because they are inexpensive. An international effort is now underway to create new varieties of crops through plant breeding, shooting for higher levels of these nutrients. --Catherine Garcia