by Marlowe Hood Agence France-Presse PARIS, France (AFP) — Rising levels of carbon dioxide in the air threaten to sap wheat, rice, and other staple grains of valuable nutrients, raising the specter of mass malnutrition, researchers warned Monday. On current trends, higher CO2 concentrations could reduce iron, zinc and protein levels in the crops that feed the world by up to 17 percent by mid-century, they reported in the journal Nature Climate Change. “Hundreds of […]