New Delhi: If carbon dioxide (CO2) levels continue to rise as projected, the populations of 47 countries across the globe may lose more than 5% of their dietary protein by 2050 due to a decline in the nutritional value of rice, wheat, and other staple crops, said a new study published on Wednesday.

The study also said that India may lose 5.3% of protein from a standard diet, putting a predicted 53 million people at new risk of protein deficiency.

The study Estimated Effects of Future Atmospheric CO2 Concentrations on Protein Intake and the Risk of Protein Deficiency by Country and Region by Harvard T.H. Chan School of Public Health was published in US based journal ‘Environmental Health Perspectives’ on Wednesday.

As per the study, researchers also estimated that roughly an additional 150 million people may be placed at risk of protein deficiency because of elevated levels of CO2 in the atmosphere.

“This study highlights the need for countries that are most at risk to actively monitor their populations’ nutritional sufficiency, and, more fundamentally, the need for countries to curb human-caused CO2 emissions," said Samuel Myers, senior research scientist in the department of environmental health of the Harvard T.H. Chan School of Public Health.

The study explained that globally 82% of the population derives most of their daily protein from plants.

To estimate their risk of protein deficiency, the researchers combined data from experiments in which crops were exposed to high concentrations of CO2 with global dietary information from the United Nations and measures of income inequality and demographics.

The study found that under elevated CO2 concentrations, the protein contents of rice, wheat, barley, and potatoes decreased by 7.6%, 7.8%, 14.1%, and 6.4%, respectively.

It also suggested continuing challenges for sub-Saharan Africa, “where millions already experience protein deficiency, and growing challenges for South Asian countries, including India, where rice and wheat supply a large portion of daily protein."

Meanwhile, another paper co-authored by Myers, which is published in another US-based journal GeoHealth, found that CO2-related reductions in iron content in staple food crops are likely to also exacerbate the already significant problem of iron deficiency worldwide.

“Those most at risk include 354 million children under 5 and 1.06 billion women of childbearing age—predominantly in South Asia and North Africa—who live in countries already experiencing high rates of anemia and who are expected to lose more than 3.8% of dietary iron as a result of this CO2 effect," the paper said.

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