Kevin Gurney and colleagues investigated the self-reported inventories of 48 cities across the US. They found that cities used different accounting methods for marine, airborne and on-road emissions, as well omission of petroleum fuel use in some cities. When comparing the self-reported emissions to independent estimates from the Vulcan CO2 emissions data product (an estimate of annual CO2 emissions from fossil fuels), the analysis suggests that the vast majority of cities under-reported emissions. For example, Indianapolis, Indiana, is found to be underestimating emissions by 26.9%. However, a few cities, such as Flagstaff, Arizona, and Madison, Wisconsin, on average were found to be over-reporting their emissions. Read more.