Climate change projected to reduce availability of nutrients
Over the next 30 years, climate change and increasing carbon dioxide (CO2) could significantly reduce the availability of critical nutrients such as protein, iron, and zinc, compared to a future without it, according to a new study published in The Lancet Planetary Health.
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 percent, 14.4 percent, and 14.6 percent, respectively.
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 led by Robert Beach, PhD, lead author, and Timothy Sulser, PhD, senior author, projected per capita availability of protein, iron, and zinc out to 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.
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 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.
The impact on individual crops can also have disproportionate effects on diets and health. Significant nutrient losses in wheat have especially widespread implications, Beach said.
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.
"Diets and human health are incredibly complex and difficult to predict,” Sulser said, “and by reducing the availability of critical nutrients, climate change will further complicate efforts to eliminate undernutrition worldwide.”