Nitrate Assimilation Is Inhibited By Elevated CO2 In Field-Grown Wheat, Nature Climate Change, 7 April 2014
Wheat that was exposed to elevated levels of carbon dioxide, about what is expected in the next couple decades, had less protein in it. All protein contains nitrogen, and these plants had difficulty taking available nitrogen and using it to make amino acids, which are the building blocks of protein.
“These findings imply that food quality will suffer under the CO2 levels anticipated during this century.”
From a University of California, Davis (UCDavis) press release:
Field Study Shows Why Food Quality Will Suffer With Rising CO2, 7 April, 2014
[Lead author Arnold Bloom, professor in Plant Sciences at UCDavis where the wheat field-test study was conducted] noted that other studies also have shown that protein concentrations in the grain of wheat, rice and barley — as well as in potato tubers — decline, on average, by approximately 8 percent under elevated levels of atmospheric carbon dioxide.
This is not good news, especially for people who get their protein from plants.