Carbon dioxide makes food less nutritious

Less nutritious crops could pose health problems for many people worldwide who rely heavily on rice as their main food source. (Rob Bertholf/flickr)

Jenna Ladd | April 5, 2018

The changing climate is forcing farmers to adapt, but how do rising greenhouse gas levels impact the food on our dinner plates?

A Harvard School of Public Health study looked at how more carbon dioxide in the atmosphere affects nutrient levels in six primary food crops: wheat, rice, field peas, soybeans, corn and sorghum. The researchers split plants of the same crop up between two groups. The first group was cultivated in an environment with between 363 and 386 parts per million carbon dioxide (CO2). This was the amount of CO2 in the atmosphere at the time of the study, in 2014. The second group of plants grew up in an environment with between 546 to 586 parts per million of the greenhouse gas in the air. This is roughly the concentration of CO2 expected to be in Earth’s atmosphere within fifty years.

When it was time, the scientists harvested the crops and measured levels of key nutrients in them. They looked specifically at zinc, protein and iron. The study found that plants grown in environments with higher concentrations of CO2 were less nutritious than their counterparts. Wheat, rice and soybeans were all found to have lower levels of zinc, protein and iron in the higher CO2 conditions.

Animal products are the primary source of protein for most people in the U.S., but people in other parts of the world rely heavily on rice and wheat as their main protein providers. These foods are naturally low in protein and further deficiency could be devastating. One study in the Journal Environmental Health Perspectives found that these projected impacts could cause an additional 150 million people worldwide to be protein deficient by 2050. Protein deficiency can cause low birth weight and other health problems that stunt growth and development.