There have been many well-funded experiments on the effects of increased carbon dioxide on plants. They show that plants increase in size, thus locking up that extra CO2 in the form of extra cellulose (fuel/energy). They also produce more oxygen, provide more shade, use less water, and in general grow more efficiently. This is a natural balancing act on the part of Mother Earth, which keeps the quantity of carbon dioxide in check so it cannot cook the planet.
If there is a bit too much CO2, the trillions of plants and their quintillions of leaves will simple lock it up and store it away whilst enriching the oxygen percentage of the atmosphere. The global warming myth was busted long ago and multiple times. See the San Jose State University article below: