The impact of climate change on food yield and nutrition

Leafy greens can provide calcium, magnesium, and potassium. (ccharmon/flickr)

Eden DeWald | June 13th, 2018

A new study, conducted by a team from the London School of Hygiene & Tropical Medicine, studies the effect that consequences of climate change will have on the yield and nutritional content of vegetables and legumes. The environmental changes analyzed in the study include any change found in ambient temperature, salinity, water availability, and concentration of carbon dioxide and ozone in the atmosphere. The study complied information from 174 published papers, which utilized a total of 1,540 studies, and conclusions based on the information which encompassed data from 40 different counties.

Variations of each environmental factor analyzed changed prospective vegetable and legume yields in different ways. For example, an increase in carbon dioxide levels was found to increase the mean yields overall, whereas an increase in tropospheric ozone concentration was found to decrease mean yields overall. However, an increase in carbon dioxide was the only factor studied that would produced an increase in mean yields, and all others were found to incur a decrease in average yields. The study could not make an overall comment about a change in food nutrition, but two papers that were analyzed found that an increase in carbon dioxide and ozone resulted significantly  decreased nutrient concentrations within root vegetables.

Vegetables and legumes provide many vital nutrients such as potassium, vitamin C, folate, and dietary fiber. They are cost effective diet staples for many people around the world. A decrease in means yields could negatively affect public health, decrease agriculture revenues, and make living a healthy life style even more expensive.


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.