Stomata act as the gate-keeper of carbon uptake and transpiration water losses and can control regional-scale carbon and water fluxes. Recent studies have found that soil moisture variations are a dominant driver for inter-annual variations in the atmospheric CO2 growth rate, both through direct and indirect effects on plant water stress. Here, I will summarize recent work on these interactions at the local and global scale, introduce novel measurements to continuously measure canopy water content at the field scale and how to integrate these concepts into a new land surface model to better constrain ecosystem fluxes from the local to the global scale.