1. A method for evaluating a carbon dioxide (CO 2 ) sequestration site, comprising: a) obtaining data relating to said sequestration site; b) from said data, generating input parameter values and associated input parameter value uncertainties; c) obtaining a reservoir simulation model for said sequestration site; d) generating multiple sets of different values for said input parameters based on said input parameter values and said input parameter value uncertainties and inputting said multiple sets into said reservoir simulation model; e) running said reservoir simulation model with said multiple sets of different values for said input parameters to generate output parameter values with associated output parameter value uncertainties; and f) converting said output parameter values with associated output parameter value uncertainties into performance metric answer product information having associated performance metric uncertainties usable in evaluating said sequestration site.