Carbon dioxide pollution promotes weed development

Increased levels of carbon dioxide in the atmosphere are benefitting weeds. Carbon dioxide acts as a fertilizer to invasive exotic grasses, resulting in higher growth rates and larger leaves. These stronger plants are also proving more resistant to the herbicide glyphosate.
The study, “Exotic C4 Grasses have Increased Tolerance to Glyphosate under Elevated Carbon Dioxide,” published in Weed Science reports the effects of elevated carbon dioxide levels on four species of grass. The research also gauged the tolerance of these plants to the most widely used herbicide for weed control glyphosate.
The four species tested are all invasive exotic plants in Australia that previously have been chemically controlled with glyphosate. The plants were grown in glasshouse experiments at ambient and elevated carbon dioxide levels. Mature plants were sprayed with the recommended amount of glyphosate. When treated with the herbicide, three of the four species showed a significantly higher survival rate under the elevated carbon dioxide levels compared with ambient levels.