Increased Levels of CO2 Threaten Quality of Food Crops, Study Says

Increased levels of carbon dioxide in the atmosphere could reduce the protein content of crop plants by as much as 20 percent, according to a new study. Researchers at the University of California, Davis say high CO2 levels interfere with the ability of plants to convert nitrate into proteins, and thus reduce their quality as food. The findings, the researchers say, suggest new fertilizers may be needed to counteract rising levels of atmospheric CO2 in the coming decades. The scientists tested how two major forms of soil nitrogen — nitrate and ammonium — affected wheat and the mustard plant, Arabidopsis, that were exposed to elevated CO2 levels. Those crops exposed to CO2 had a reduced ability to produce nitrogen-containing compounds, including proteins. “Wheat grain that has been exposed to conditions that we expect in the next few decades declines about 20 percent,” said Arnold Bloom, lead author of the study, published in the journal Science. As CO2 levels rise, the scientists said, there will be an increased urgency for farmers to carefully manage nitrogen to assure the productivity and quality of crops.