Urban GHG accounting: discrepancies, constraints and opportunities

To date, many cities have engaged in efforts to become more sustainable. These efforts often are translated into measures to reduce their greenhouse gas (GHG) emissions, leading to a proliferation of standards and methods. Discrepancies exist between these various accounting approaches in terms of the definition of system boundaries, allocation procedures, quality of data, and the reporting and verification of results. This paper examines some of the most important theoretical and practical issues and challenges of urban-related GHG accounting and highlights how existing approaches deal with these. Three different GHG emission accounting standards are compared and critically analysed: the Global Protocol for Community-Scale Greenhouse Gas Emissions (GPC), Bilan Carbone and ISO 14064-1:2018. The Organizational Environmental Footprint (OEF) and a previous analysis about footprinting performed by the European Commission are used as analytical lenses. Based on this analysis, suggestions are made for enhancing comprehensiveness and transparency, and providing guidelines for driving cities towards a more low-carbon path.