High CO₂ concentration in leaf interior will cause

High CO₂ concentration in the leaf interior will cause Stomatal closure.
Higher than ambient CO₂ concentrations mediate a closure of stomatal pores in plants and conversely, low CO₂ concentrations trigger the opening of stomatal pores.
Stomatal opening is induced by low CO₂ concentrations, high light intensity and high humidity. By contrast, closing is promoted by high CO₂ concentrations, darkness, drought and the plant hormone ABA.