The nutritional quality of key food crops could be compromised by growth under elevated concentrations of atmospheric carbon dioxide, reports a paper published online in Nature (https://www.nature.com/nature/journal/vaop/ncurrent/full/nature13179.html).  

Samuel Myers and colleagues gathered together data from a series of open-air CO₂-enichement experiments to show that wheat, rice, field pea and soybean plants contain lower levels of zinc and iron when grown under elevated concentrations of carbon dioxide expected by the middle of this century, as opposed to present-day conditions. A drop in the protein content of wheat and rice grown under high-CO₂ conditions is also reported.  

Around two billion people depend on crops for their dietary intake of zinc and iron. A CO₂-indcued reduction in the nutritional value of these crops could therefore pose health problems for a significant fraction of the world population.

Cultivar-dependent differences in the extent of zinc and iron reductions could be exploited in breeding programmes to help counter some of the deleterious effects of rising levels of CO₂ on crop nutrient content, the researchers note.

The latest IPCC climate impacts report (https://www.ipcc.ch/report/ar5/wg2/) suggests that food production could be compromised by climate change over the coming century.  Strategies to bolster agricultural production and safeguard food supplies for some of the most vulnerable – in the wake of continued warming and an increase in the prevalence of extreme events – are discussed in a web focus that accompanies this month’s issue of Nature Geoscience (https://www.nature.com/ngeo/focus/agriculture/index.html).  The importance of developing region-specific solutions and legislation that protects the interests of local land owners is explored.