One of the silver linings of climate change, some have argued, is that high carbon dioxide levels will mean increased crop yields, which will, in turn, be good for combating global hunger (the logic, I suppose, being that if we're frying fifty years from now, at least we won't be hot and hungry). But some underpublicized studies, reported this month in Nature, cast a long shadow on this sunny assertion. (Sorry! It looks like the the article is subscription only, so I'll be as descriptive as possible.)
In the 1980s, Bruce Kimball, a soil physicist with the USDA in Arizona, began conducting scientific experiments simulating a high-CO2 environment (using a system called "free air carbon dioxide enrichment," or FACE). He found that crop yields were elevated -- plants imbibing large quantities of CO2 had more starch and more sugar in their leaves than those on a normal carbon diet. But because they also took up less nitrogen from the soil, they made less protein.
