Increased atmospheric concentrations of carbon dioxide (CO2)

) in the atmosphere can have a fertilizing effect on certain crops, provided that it is possible for farmers to provide adequate water and fertilizer for the plants to grow more quickly. For this reason, many non-scientists have long held that increases in global atmospheric carbon dioxide will also lead to increased agricultural production, offsetting any shortages due to shifting water availability and increased temperature. This in turn, these individuals argue, will lead to decreased global malnutrition and undernutrition as the increased supply of food drives down its cost.

However, research on the nutritional content of crops grown at Free Air (CO2)

Enrichment - or FACE - sites suggests that while crops may grow more quickly in elevated concentrations of carbon dioxide, increased growth comes at a price. Crops grown in elevated levels of carbon dioxide have lower levels of protein and of micronutrients such as zinc. Since the world’s population gets the majority of its protein and other micronutrients from plant-based sources, such a shift could have dire consequences. Scientists estimate that by 2050 an additional 175 million people could become zinc deficient, and an additional 120 million could become protein deficient as the nutritional content of staple crops falls between 5 and 17 percent.

Which of the following can be inferred from the passage?

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