EASY GEO-CARBON proposes an integrated experimental-modeling workflow to ‎substantially improve the knowledge of CO₂ interactions with rocks and their potential impacts on ‎short- and long-term response of the subsurface to CO₂ storage. To achieve this goal, we will inject CO₂ into reservoir rock samples in the laboratory under representative underground conditions to reach an in-depth understanding and develop a mathematical formulation of coupled Hydraulic-Mechanical-Chemical (HMC) processes that occur in rock as a result of CO₂ injection. We will incorporate the model into an open-access numerical code and validate it by reproducing laboratory observations. We will finally use this numerical tool to simulate megatonne-scale CO₂ injection at two sites. The developed knowledge of coupled HMC processes in rock during CO₂ injection puts more reliable constraints ‎on reservoir injectivity and storage capacity‎ and provides a more realistic understanding of the risks associated with induced seismicity and CO₂ leakage towards the surface, two obstacles that in part fed into delays in widespread deployment of Carbon Capture and Storage in deep geological formations, also referred to as geologic carbon storage. Thus, the successful development of EASY GEO-CARBON will pave the way for optimized ‎geologic carbon storage and its rapid and vast scale-up.