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If CO2 levels continue to rise as projected, the populations of 18 countries 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, according to new findings from Harvard T.H. Chan School of Public Health.
Researchers estimate that roughly an additional 150 million people may be put at risk of protein deficiency because of higher levels of CO2 in the atmosphere. This is the first study to quantify this risk.
Globally, 76% of the population derives most of its daily protein from plants. To estimate the current and future 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.
They found that under higher concentrations of CO2, the protein contents of rice, wheat, barley and potatoes decreased by 7.6%, 7.8%, 14.1% and 6.4%, respectively.
The results suggest 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.
The researchers found that India may lose 5.3% of protein from a standard diet, putting a predicted 53 million people at new risk of protein deficiency.
‘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.’
SAMUEL MYERS
Senior research scientist in the Department of Environmental Health
A companion paper co-authored by Myers, published as an Early View article in GeoHealth, found that CO2-related reductions in the iron content of staple food crops are also likely to exacerbate the already significant problem of global iron deficiency.
Those most at risk include 354 million children under five and 1.06 billion women of childbearing age – predominantly in South Asia and North Africa – who live in countries already experiencing high rates of anaemia and who are expected to lose more than 3.8% of dietary iron as a result of this CO2 effect.
These two studies, taken alongside a 2015 study co-authored by Myers showing that elevated CO2 emissions are also likely to drive roughly 200 million people into zinc deficiency, quantify the significant nutritional toll expected to arise from human-caused CO2 emissions.
‘Strategies to maintain adequate diets need to focus on the most vulnerable countries and populations, and thought must be given to reducing vulnerability to nutrient deficiencies through supporting more diverse and nutritious diets, enriching the nutritional content of staple crops, and breeding crops less sensitive to these CO2 effects. And, of course, we need to dramatically reduce global CO2 emissions as quickly as possible.’
SAMUEL MYERS
Senior research scientist in the Department of Environmental Health
Click here to read the study, ‘Estimated Effects of Future Atmospheric CO2 Concentrations on Protein Intake and the Risk of Protein Deficiency by Country and Region’, in Environmental Health Perspectives.
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