Farmer in Zaouia village, Morocco. Researchers expect reductions in nutrient availability during the next decades.
Photo: ©IFAD/Giulio Napolitano

Rising CO2 reduces nutrient availability

While higher levels of CO2 can boost plant growth, they reduce the concentration of key micronutrients in crops. Researchers from IFPRI projected the per capita availability of protein, iron, and zinc out to 2050 and found that rising CO2 would reduce availability of nutrients worldwide.

Over the next 30 years, climate change and increasing carbon dioxide (CO2) could significantly reduce the availability of critical nutrients compared to a future without climate change, the International Food Policy Research Institute (IFPRI) warns in July 2019.

The total impacts of climate-change shocks and elevated levels of CO2 in the atmosphere are estimated to reduce growth in global per-capita nutrient availability of protein by 19.5 per cent, iron by 14.4 per cent and zinc by 14.6 per cent by the year 2050.

Improvements in technology, and market effects are projected to increase nutrient availability over current levels by 2050, but these gains are substantially diminished by the negative impacts of rising concentrations of carbon dioxide.

While higher levels of CO2 can boost photosynthesis and growth in some plants, they reduce the concentration of key micronutrients in crops. Wheat, rice, maize, barley, potatoes, soybeans and vegetables are all projected to suffer nutrient losses of about 3 per cent on average by 2050 due to elevated CO2 concentration.

Nutrient reductions differ from region to region

The effects are not likely to be felt evenly around the world, however, and many countries currently experiencing high levels of nutrient deficiency are also projected to be more affected by lower nutrient availability in the future, the researchers say.

Nutrient reductions are projected to be particularly severe in South Asia, the Middle East, Africa south of the Sahara, North Africa, and the former Soviet Union. These regions are largely comprised of low- and middle-income countries where levels of undernutrition are generally higher, and diets are more vulnerable to  direct impacts of changes in temperature and precipitation triggered by climate change.

This means that many people with already relatively low nutrient intake will likely become more vulnerable to deficiencies in iron, zinc and protein as crops lose their nutrients. Many of these regions are also the ones expected to fuel the largest growth in population, thus requiring the most growth in nutrient availability.

Although the study’s models were limited to 2050, the researchers point out that the reductions in nutrient availability would be even greater when climate change is expected to have even stronger impacts in the second half of this century.


More information at IFPRI website:

Read the study Combining the effects of increased atmospheric carbon dioxide on protein, iron and zinc availability and projected climate change on global diets: a modelling study published in The Lancet Planetary Health, Volume 3, Issue 7, July 2019, Pages e307-e317:

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