Global changes such as elevated carbon dioxide [eCO2] and warming have been described as the most serious environmental threats to our planet. Elevated CO2 may have important consequences on forested ecosystems. Although, the impact is worse in dryland ecosystems as atmospheric changes increase aridity and change soil fertility, but it remains unknown. The study aiming at understanding the effects of eCO2 and its consequences on Hashab (Acacia senegal) as a dryland C3 tree species with substantial ecological and economic roles. We quantitatively reviewed and discussed over 50 papers on the literature about CO2 elevation (eCO2) effects on C3 plant and ecosystems to understand how eCO2 will affect dryland C3 species of sub-Saharan Africa. We found in the literature that, for C3 species generally eCO2 increases photosynthesis rate and reduces stomatal conductance but with increased plant leaves’ area leading to release water. Water loss due to stomatal conductance is unavoidable in dryland ecosystems. More seeds can be produced in eCO2 but with mostly correlated seed low quality which may limit seedling recruitment. Seedlings, as the most responsive stage to eCO2, may respond by enhancing growth and biomass production or experience photosynthesis down regulation and/or photorespiration. The results suggested that A. senegal, as a C3 and leguminous species will respond to eCO2 by two scenarios; 1) positively through enhancing growth and biomass or; 2) a negative photosynthetic acclimation that could be due to physiological dysfunction that resulted in metabolic compulsions. The responses need to be further investigated under different ecological conditions to feedback the global changes and ecosystem monitoring including changes of species composition is recommended.