Rising CO2 to deplete crop nutrients in Africa, globally – Study
Within the next 30 years, increasing carbon dioxide (CO2) could significantly reduce the availability of critical crop nutrients such as protein, iron, and zinc in Africa and globally, a new study finds.
According to the study, 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, iron and zinc by 19.5, 14.4, and 14.6 percent respectively.
One of the biggest challenges to reducing hunger and under-nutrition globally is by producing foods that provide not only enough calories but also make enough necessary nutrients widely available.
“We have made a lot of progress reducing under-nutrition around the world recently but global population growth over the next 30 years will require increasing the production of foods that provide sufficient nutrients,” Timothy Sulser, senior scientist at the International Food Policy Research Institute (IFPRI) and study co-author said in a statement.
“These findings suggest that climate change could slow progress on improvements in global nutrition by simply making key nutrients less available than they would be without it,” Sulser said.
The study, ‘A modeling approach combining elevated atmospheric CO2 effects on protein, iron and zinc availability with projected climate change impacts on global diets’ was co-authored by an international group of researchers and published in the peer-reviewed journal, Lancet Planetary Health.
It represents the most comprehensive synthesis of the impacts of elevated CO2 and climate change on the availability of nutrients in the global food supply to date.
Using the IMPACT global agriculture sector model along with data from the Global Expanded Nutrient Supply (GENuS) model and two data sets on the effects of CO2 on nutrient content in crops, researchers projected per capita availability of protein, iron, and zinc to out by 2050.
Improvements in technology and markets 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, the study stated.
While higher levels of CO2 can boost photosynthesis and growth in some plants, previous research has also found they reduce the concentration of key micronutrients in crops, the study finds.
The new study finds that wheat, rice, maize, barley, potatoes, soybeans, and vegetables are all projected to suffer nutrient losses of about 3 percent on average by 2050 due to elevated CO2 concentration.
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, it said.
The study said that nutrient reductions are projected to be particularly severe in South Asia, the Middle East, Sub Sahara Africa, North Africa, and the former Soviet Union—regions largely comprised of low- and middle-income countries where levels of under-nutrition are generally higher and diets are more vulnerable to direct impacts of changes in temperature and precipitation triggered by climate change.
“In general, people in low- and middle-income countries receive a larger portion of their nutrients from plant-based sources, which tend to have lower bioavailability than animal-based sources,” said Robert Beach, senior economist and Fellow at RTI International and lead author of the study.
“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 populations and thus requiring the most growth in nutrient availability” he said.
“The impact on individual crops can also have disproportionate effects on diets and health. Significant nutrient losses in wheat have especially widespread implications. “Wheat accounts for a large proportion of diets in many parts of the world, so any changes in its nutrient concentrations can have substantial impact on the micronutrients many people receive,” added Beach.
The researchers also emphasized the need for further work to build upon their findings, including additional study of climate impacts on animal sources, such as poultry, livestock, and fisheries, crops’ nutritional composition, nutrient deficiencies resulting from short-term climate shocks, and technologies that could mitigate reductions in nutrient availability.
Quantifying the potential health impacts for individuals also requires a consideration of the many factors beyond food consumption—including access to clean water, sanitation, and education—that influence nutrition and health outcomes.