The Boston Globe reports, "Harvard researchers say rising levels of carbon dioxide are going to have an impact in a place you might not expect: hundreds of millions of people’s diets worldwide, which will become less nutritious. Crops such as rice and wheat become less nutritious when carbon dioxide levels are higher, the researchers from the Harvard T.H. Chan School of Public Health said in a statement.
The researchers said that humans tend to get most of their key nutrients from plants — 63 percent of their protein, 81 percent of their iron, and 68 percent of their zinc. Crops provide less of those nutrients when carbon dioxide is higher."