According to a study published in the latest edition of Weed Science, carbon dioxide acts as a fertilizer to invasive exotic grasses, resulting in higher growth rates and larger leaves, and makes them more resistant to glyphosate, an herbicide commercially known as Roundup.
The study looked at the effects of elevated carbon dioxide levels on four species of grass and gauged the tolerance of these plants to glyphosate. The four species tested are all invasive exotic plants in Australia that have previously been chemically controlled with glyphosate. When treated with the herbicide, three of the four species showed a significantly higher survival rate under elevated carbon dioxide levels compared with ambient levels.

Based on the study's results, the use of herbicides may need to be increased to counter the effects of stronger weeds — a move that could have significant implications for affected industries.