Nutritional deficiency is already a major global health concern. And now, a study has found the rising levels of carbon dioxide in the atmosphere owing to climate change, which may reduce the nutritional quality of some of the most important food crops in the world.

Researchers reached at the above given conclusion after carrying out experiments simulating the atmospheric conditions expected by mid-century. The temperature is expected to reach 550 ppm in the next four to five decades.

After creating the conditions to prevail in mid-century, researchers noticed the amounts of two important nutrients, zinc and iron to be lower in wheat, rice, soyabeans and field peas in open-air fields. In total, 40 varieties of six different grains and legumes were grown including corn and sorghum at seven places in three continents, the United States, Japan and Australia.

Researchers noticed wheat grown under elevated CO2 conditions to have 9% of lower level of zinc and 5% lower level of iron when compared to wheat grown under normal conditions. The rice grown with increased CO2 levels had 3% less zinc and 5% less iron.

Lower protein content was also noticed in wheat and rice when grown under the elevated carbon dioxide levels. Rice, wheat and soyabeans has increased amount of sugars through photosynthesis at the increased CO2 levels.

No change was seen in nutrients in sorghum and corn at higher carbon dioxide levels as these crops uses such a type of photosynthesis that has CO2 in their leaves.

A system known as Free Air Concentration Enrichment (FACE) was used to replicate higher CO2 levels in open air-fields. The system pumps out, monitors and adjusts ground level CO2 in air to imitate future conditions.

"We found that elevated carbon dioxide was associated with significant decreases in the concentrations of zinc and iron", affirmed researchers in the Journal Nature.