In the future, Earth's atmosphere is likely to include a whole lot more carbon dioxide. And many have been puzzling over what that may mean for the future of food crops. Now, scientists arereporting that some of the world's most important crops contain fewer crucial nutrients when they grow in such an environment.
The data come from experiments that have been set up to see how crops will perform as levels of carbon dioxide in the air soar past 500 parts per million. (The current level is around 400 ppm.)
These experiments are operating in various parts of the world, and have included test plots of rice, wheat, peas and other crops.
Samuel Myers, a researcher at Harvard's School of Public Health, says these experiments take place in open fields, "except that in the field are placed rings of carbon dioxide jets." These jets release just enough carbon dioxide to simulate the atmosphere that crops will almost certainly experience 40 to 60 years from now.
In general, the experiments show that crops grow faster when there's more carbon dioxide, and yields are often 10 percent higher, compared with plants in normal atmosphere.
But Myers and his colleagues took a closer look, examining not just the quantity of the harvest, but also its quality.
"What we found were 5 to 10 percent reductions in nutrients like iron, zinc and protein," he says.
Myers isn't sure what's causing this. One theory is that when a plant produces more grain or beans, the trace nutrients get diluted.
Written By: Dan Charles
continue to source article at npr.org