Plants take in CO2 for photosynthesis through the stomata (pores) on their leaves and they respire Oxygen. But, when stomata open, water is transpired (lost). Higher levels of CO2 means that the photosynthesis is more efficient and the stomata don’t have to stay open as long. Therefore, plants transpire less water and become much more efficient at managing drought under climatic conditions (i.e. high CO2) that contribute to climate change.
It is just one study. But, hopefully, more work will be done. Because these findings potentially could change some of the climate change models for agriculture
Climate Chans has Less Impact on Drought than Previously Expected. University of California, Irvine. August 29, 2016. https://www.sciencedaily.com/releases/2016/08/160829163305.htm