Global sampling for integrating physics-specific subsystems and quantifying uncertainties of CO2 geological sequestration

► Global sampling method is introduced for quantifying uncertainties. ► Reduced-order models (ROMs) are developed from high-fidelity simulations. ► Leakage relevant risk measures are emulated with probability density distributions. ► Fault permeability is the most sensitive parameter to the impact of CO2 leakage. ► Heterogeneity is quantitatively described using indicator transition probability.