From the CO2Science archive: If you saw our video on global greening you learned about C3 versus C4 plants, and you will know that C3 plants starve for CO2 when levels are low because they aren’t as efficient at using it as C4 plants. The CO2Science archive reports that in 2019 there were 5 experiments exposing Stipa baicalensis, a common grass species in the C3 group, to extra CO2. In response to an extra 300 ppm the average growth boost was 105%, meaning the plants doubled in size. Greening indeed.