Monitoring subsurface CO2 emplacement and security of storage using muon tomography

► Monitoring CO2 migration during carbon geostorage is a major challenge. ► Cosmic-ray muon tomography could be used for CO2 monitoring in a geostorage site. ► We have developed a simple model to test the sensitivity of the method. ► We can detect as little as 0.4% change in the mean reservoir density at 1 km depth. ► Muon detection could monitor migration of CO2 continuously and inexpensively.