The nutritious value of some grains and legumes will become significantly less with the rise in levels of carbon dioxide this century, a warning for future farmers and eaters, say researchers.
The new findings are reported in the journal Nature
. Eight institutions, from Australia, Israel, Japan and the United States, contributed to the analysis.
The researchers looked at multiple varieties of wheat, rice, field peas, soybeans, maize and sorghum grown in fields with atmospheric carbon dioxide levels like those expected in the middle of this century. (Atmospheric CO2
concentrations are currently approaching 400 parts per million, and are expected to rise to 550 ppm by 2050.)
The teams simulated high CO2
levels in open-air fields using a system called Free Air Concentration Enrichment (FACE), which pumps out, monitors and adjusts ground-level atmospheric CO2
to simulate future conditions. In this study, all other growing conditions (sunlight, soil, water, temperature) were the same for plants grown at high-CO2
and those used as controls.The experiments revealed that the nutritional quality of a number of the world's most important crop plants dropped in response to elevated CO2
The study contributed "more than tenfold more data regarding both the zinc and iron content of the edible portions of crops grown under FACE conditions" than available from previous studies, the team wrote.