Quantcast
Environmental News for a Healthier Planet and Life

Rising CO2 Levels Will Make Staple Crops Less Nutritious

Food

At the elevated levels of atmospheric carbon dioxide (CO2) anticipated by around 2050, crops that provide a large share of the global population with most of their dietary zinc and iron will have significantly reduced concentrations of those nutrients, according to a new study led by Harvard School of Public Health (HSPH). Given that an estimated 2 billion people suffer from zinc and iron deficiencies—resulting in a loss of 63 million life years annually from malnutrition—the reduction in these nutrients represents the most significant health threat ever shown to be associated with climate change.

Researchers tested the nutrient concentrations of the edible portions of wheat and rice — among other crops — and found a significant decrease in the concentrations of zinc, iron, and protein.

“This study is the first to resolve the question of whether rising CO2 concentrations—which have been increasing steadily since the Industrial Revolution—threaten human nutrition,” said Samuel Myers, research scientist in the Department of Environmental Health at HSPH and the study’s lead author. The study appears online May 7 in Nature.

Some previous studies of crops grown in greenhouses and chambers at elevated CO2 had found nutrient reductions, but those studies were criticized for using artificial growing conditions. Experiments using free air carbon dioxide enrichment (FACE) technology became the gold standard as FACE allowed plants to be grown in open fields at elevated levels of CO2, but those prior studies had small sample sizes and have been inconclusive.

The researchers analyzed data involving 41 cultivars (genotypes) of grains and legumes from the C3 and C4 functional groups (plants that use C3 and C4 carbon fixation) from seven different FACE locations in Japan, Australia and the U.S. The level of CO2 across all seven sites was in the range of 546 to 586 parts per million (ppm). The researchers tested the nutrient concentrations of the edible portions of wheat and rice (C3 grains), maize and sorghum (C4 grains), and soybeans and field peas (C3 legumes).

The results showed a significant decrease in the concentrations of zinc, iron and protein in C3 grains. For example, zinc, iron and protein concentrations in wheat grains grown at the FACE sites were reduced by 9.3 percent, 5.1 percent, and 6.3 percent, respectively, compared with wheat grown at ambient CO2. Zinc and iron were also significantly reduced in legumes; protein was not.

The finding that C3 grains and legumes lost iron and zinc at elevated CO2 is significant. Myers and his colleagues estimate that 2 billion to 3 billion people around the world receive 70 percent or more of their dietary zinc and/or iron from C3 crops, particularly in the developing world, where deficiency of zinc and iron is already a major health concern.

C4 crops appeared to be less affected by higher CO2, which is consistent with underlying plant physiology, as C4 plants concentrate CO2 inside the cell for photosynthesis, and thus they might be expected to be less sensitive to extracellular changes in CO2 concentration.

The researchers were surprised to find that zinc and iron varied substantially across cultivars of rice. That finding suggests that there could be an opportunity to breed reduced sensitivity to the effect of elevated CO2 into crop cultivars in the future.

In addition to efforts to reduce CO2 emissions, breeding cultivars with reduced sensitivity to CO2, biofortification of crops with iron and zinc, and nutritional supplementation for populations most affected could all play a role in reducing the human health impacts of these changes, said Myers. “Humanity is conducting a global experiment by rapidly altering the environmental conditions on the only habitable planet we know. As this experiment unfolds, there will undoubtedly be many surprises. Finding out that rising CO2 threatens human nutrition is one such surprise,” Myers said.

Other HSPH authors include Antonella Zanobetti, Itai Kloog and Joel Schwartz.

--------

YOU MIGHT ALSO LIKE

Maple Syrup Threatened by Climate Change

8 Foods That California's Drought Will Make More Costly

Climate Change Causes Spike in Coffee Prices 

--------

EcoWatch Daily Newsletter

An aerial view of a crude oil storage facility of Caspian Pipeline Consortium (CPC) in the Krasnodar Territory. Vitaly Timkiv / TASS / Getty Images

Oil rigs around the world keep pulling crude oil out of the ground, but the global pandemic has sent shockwaves into the market. The supply is up, but demand has plummeted now that industry has ground to a halt, highways are empty, and airplanes are parked in hangars.

Read More Show Less
Examples (from left) of a lead pipe, a corroded steel pipe and a lead pipe treated with protective orthophosphate. U.S. EPA Region 5

Under an agreement negotiated by community groups — represented by NRDC and the Pennsylvania Utility Law Project — the Pittsburgh Water and Sewer Authority (PWSA) will remove thousands of lead water pipes by 2026 in order to address the chronically high lead levels in the city's drinking water and protect residents' health.

Read More Show Less
Sponsored
ROBYN BECK / AFP / Getty Images

By Dave Cooke

So, they finally went and did it — the Trump administration just finalized a rule to undo requirements on manufacturers to improve fuel economy and reduce greenhouse gas emissions from new passenger cars and trucks. Even with the economy at the brink of a recession, they went forward with a policy they know is bad for consumers — their own analysis shows that American drivers are going to spend hundreds of dollars more in fuel as a result of this stupid policy — but they went ahead and did it anyway.

Read More Show Less

By Richard Connor

A blood test that screens for more than 50 types of cancer could help doctors treat patients at an earlier stage than previously possible, a new study shows. The method was used to screen for more than 50 types of cancer — including particularly deadly variants such as pancreatic, ovarian, bowel and brain.

Read More Show Less
Ian Sane / Flickr

Preliminary data from the Centers for Disease Control showed a larger number of young people coming down with COVID-19 than first expected, with patients under the age of 45 comprising more than a third of all cases, and one in five of those patients requiring hospitalization. That also tends to be the group most likely to use e-cigarettes.

Read More Show Less