Researchers have already warned that rising carbon dioxide levels will cause rice to become less nutritious. Now, a report published on Tuesday has suggested this could result in 125.8 million years of healthy life lost around the world.
The new research, published in the journal PLOS Medicine, states that less nutritious crops could lead to increased malnutrition, which could then prompt sickness.
"We expect nutrient deficiencies to really increase dramatically from higher carbon dioxide in the atmosphere," Dr. Sanjay Basu, one of the study’s authors and assistant professor of medicine at Stanford University School of Medicine, told NPR. "In the long run, I think it's likely to cause some chronic problems we haven't prepared for."
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The new report built on earlier research published in May, exploring the effects of rising carbon dioxide on rice — by testing 18 different kinds in China and Japan between 2010 and 2014.
Crops subject to higher levels of carbon dioxide were usually less nutritious, no matter where the rice was grown.
The rice had about 10% less protein, 8% less iron, and 5% less zinc than rice grown in today’s concentrations of carbon dioxide, according to The Guardian. Levels of vitamins B1, B2, B5, and B9 also dropped — B9 levels actually dropped by more than 30%.
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But then a research team from Stanford University decided to look at how those findings might impact people in the future, using current data about carbon dioxide and crop nutrients.
It is anticipated that the study’s countries will see increases in carbon dioxide concentration from approximately 400 ppm to 550 ppm between 2015 and 2050.
Carbon dioxide levels are higher than they have been in the last 800,000 years, according to the National Oceanic and Atmospheric Administration.
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These increased carbon dioxide levels would make crops less nutritious. And when crops become less nutritious, food becomes less nutritious. When people lack enough nutrients, they are more likely to get sick.
The researchers were able to forecast how many people would become nutrient-deficient because of their less nutritious diet. Following that, they anticipated changes in diseases rates.
The reduction in zinc and iron levels in crops caused by rising levels of carbon dioxide would result in 125.8 million disability life years (DALY) from now until 2050, primarily affecting South-East Asian and sub-Saharan African countries, according to the report.
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One DALY is seen as one lost year of “healthy” life, according to the World Health Organization.
The study also looked at various solutions to this issue.
"Some of the climate change mitigation policies might be even more effective than public health measures to help avert this problem," Basu told NPR.
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They found that traditional public health initiatives, like nutrient supplementation and disease control campaigns, were expected to cut this by 26.6%.
But if carbon dioxide levels were cut down to the levels outlined in a strategy like the Paris Agreement, 48.2% of this burden could be alleviated, according to the report.
Some argue that results in a preventative study like this cannot be confirmed as 100% accurate, as findings are based on a number of assumptions that could change.
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"We don't have highly accurate information about what everyone in the world is eating," Dr. Samuel Myers, senior research scientist at Harvard T.H. Chan School of Public Health, told NPR.
Global diets could change, crops could become resistant to climate change, and carbon dioxide levels could even decrease.
Still, the study offers a blunt look at how carbon dioxide emissions could affect some of the world’s most vulnerable populations, as well as the important of climate change mitigation.