As more carbon dioxide enters the atmosphere compliments of global warming, crops will indeed grow faster, but Harvard scientists have stumbled upon a big downside, too. They placed "rings of carbon dioxide jets" amid rice, wheat, peas, and other crops around the world to study what happens when the air's carbon dioxide level increases from its current 400 parts per million to 500, which should happen over the next four to six decades—and found that while yields could balloon some 10%, "you get big plants but nothing to eat," one scientist not involved in the study trumpets to NBC News. That's because the plants ended up being less nutritious. In the case of wheat, zinc dropped 9%, protein 6%, and iron 5%.
The researcher who headed up the study theorizes that the plant's increased yield could cause those nutrients to be, as NBC News puts it, diluted. That could mean that people would need to ingest more calories from these crops to get the same amount of nutrients, or that they'll eat the same amount and suffer from iron and zinc deficiencies, something NPR reports 2 billion people around the planet already experience. The former negatively impacts kids' IQ; the latter hampers the immune system. But researchers are working to solve the problem. They hope to create more nutrient-filled crop varieties through plant breeding; they've already succeeded with some rice and wheat varieties, though a USDA researcher says doing is a formidable challenge. (Click to see how scientists plan to feed the world meat in 2050.)