The findings challenge a common argument floated among doubters of accepted climate science—that rising CO2 concentrations are a net positive for global vegetation, including crops.
Rep. Lamar Smith, a Texas Republican who leads the House Science, Space and Technology Committee, is one outspoken proponent of the idea. In an essay published last summer in The Daily Signal, he argued that more carbon dioxide will lead to increased plant growth, spurring “a greater volume of food production and better quality food.”
But the new research—and other studies published before it—discredit those claims.
“We have some rice varieties that show a stronger response to CO2 and they are able to convert more of that CO2 into seed, which can be good,” said senior study author Lewis Ziska, a scientist with the Department of Agriculture. “On the other side of that coin is the quality of that seed also being diminished in response to CO2.”