Carbon dioxide helps plants to grow, so more CO2 in the atmosphere may actually seem a positive for agriculture. But, recent studies have shown that crops exposed to the higher levels of CO2 we may see later this century have lower amounts of vital nutrients. This is a problem--already there are "billions of people ... who don't get enough protein, vitamins, or other nutrients in their daily diet." A 2018 study saw this happen with 18 varieties of rice; a 2014 study found this effect in wheat, rice, peas, and soybeans. While it may be theoretically possible to genetically engineer crops to overcome this deficit, there are big challenges and no guarantees. "The bottom line is that people will need more diverse diets with a range of quality food sources" to get the nutrients they need to stay healthy and that is already a challenge in both poor and rich countries.
How More Carbon Dioxide Can Make Food Less Nutritious: Carbon dioxide helps plants grow. But a new study shows that rice grown in higher levels of carbon dioxide has lower amounts of several important nutrients.