Updating the input-output database is a crucial part for the development of large-scale economywide equilibrium models designed for various policy impact analyses. While it is often preferable to adopt the latest database for modeling exercises, the implications of this update are much less examined in existing literature. In this study, we provide a critical evaluation of upgrading the inputoutput data of a global energy-economic computable general equilibrium model. Specifically, we will answer the following question: How could datasets with different reference years affect results of policy simulations that aim at reducing CO2 emissions? We find that higher mitigation costs across regions using data for the year of 2011, as opposed to cases using the 2007 and 2004 data—an observation that could be explained by the increasing fossil fuels prices over time. We also provide an analytical framework and numerical examples to support our argument, and propose an adjustment to address the concerns of using input-output data that embed the combination of energy prices and the related consumption levels deviating from a more sustainable state.