Of all the threats posed by climate change, who would have guessed that “[g]iven that an estimated 2 billion people suffer from zinc and iron deficiencies, resulting in a loss of 63 million life years annually from malnutrition, the reduction in these nutrients represents the most significant health threat ever shown to be associated with climate change”?
Todd Datz, Harvard School of Public Health Communications, reports for the Harvard Gazette on a new study led by HSPH:
At the elevated levels of atmospheric CO2 anticipated by around 2050, crops that provide a large share of the global population with most of their dietary zinc and iron will have significantly reduced concentrations of those nutrients, according to a new study led byHarvard School of Public Health (HSPH). Given that an estimated 2 billion people suffer from zinc and iron deficiencies, resulting in a loss of 63 million life years annually from malnutrition, the reduction in these nutrients represents the most significant health threat ever shown to be associated with climate change.
“This study is the first to resolve the question of whether rising CO2concentrations — which have been increasing steadily since the Industrial Revolution — threaten human nutrition,” said Samuel Myers, research scientist in the Department of Environmental Health at HSPH and the study’s lead author.
The study appears online May 7 in Nature.
Some previous studies of crops grown in greenhouses and chambers at elevated CO2 had found nutrient reductions, but those studies were criticized for using artificial growing conditions. Experiments using free air carbon dioxide enrichment (FACE) technology became the gold standard as FACE allowed plants to be grown in open fields at elevated levels of CO2, but those prior studies had small sample sizes and have been inconclusive.
The researchers analyzed data involving 41 cultivars (genotypes) of grains and legumes from the C3 and C4 functional groups (plants that use C3 and C4 carbon fixation) from seven different FACE locations in Japan, Australia, and the United States. The level of CO2 across all seven sites was in the range of 546 to 586 parts per million (ppm). The researchers tested the nutrient concentrations of the edible portions of wheat and rice (C3 grains), maize and sorghum (C4grains), and soybeans and field peas (C3 legumes).
The results showed a significant decrease in the concentrations of zinc, iron, and protein in C3 grains…
[continues at the Harvard Gazette]