On average, people around the world receive most of their nutrition from plants, including 63 percent of total dietary protein, 68 percent of zinc, and 81 percent of iron. Because so many people in the world get their nutrition from plants, and because plants are uniquely affected by higher CO2 concentrations, it is likely that large parts of the world would consume less protein, iron, and zinc coming from crops in 2050 unless significant measures are taken to counteract nutrient leaching. Read more.