Carbon emissions are nowadays an important driver of the value of a firm. We are the first to analyze the potential of carbon emissions data in enhancing the accuracy of firm valuations using the similar public company methodology with multiples. Using carbon emissions has a potential to improve firm valuation accuracy in two separate ways. First, we construct multiples based on carbon emissions (CEM) which are able to estimate firm values. And second, we create more precise peer groups by including carbon emissions (CEPG) in the composition process. To gain deeper insights, we are conducting further analyses, e.g. by measuring the accuracy of carbon emissions peer groups and carbon emissions multiples at valuing carbon intensive or carbon inefficient firms. We extend our study by looking at firms in countries with carbon pricing or by taking ESG and SDGs concerns into account. Overall, we find that CEPG improves the accuracy of firm valuations in more than three quarters of all cases whereas CEM have limited use. Therefore, we recommend analysts, asset managers and investors to include carbon emissions data into their peer group composition.