Three‐scope carbon emission inventories of global cities

A major challenge for cities taking action on climate change is assessing and managing the contribution of urban consumption which triggers greenhouse gas (GHG) emissions outside city boundaries. Using a novel method of creating city‐level input–output tables, we present the first consistent, large‐scale, and global assessment of three‐scope GHG inventories for 79 members of the C40 Cities Climate Leadership Group. These inventories cover the emissions from sources located within city boundaries (Scope 1), emissions occurring as a consequence of the use of grid‐supplied electricity, heat, steam, and/or cooling (Scope 2), and all other GHG emissions that occur outside the city boundary as a result of activities taking place within the city (Scope 3). We find that, by only accounting for territorial emissions, without Scope 3, the 79 C40 cities under‐report 4% of global annual GHG emissions from six key infrastructure‐related transboundary sources (73%) and from service‐related sectors (27%). In contrast, when only accounting for consumption‐based emissions, the C40 cities would miss the mitigation target on 41% of their territorial emissions. We argue that cities should complement their GHG inventories, adding full Scope 3 to Scopes 1 and 2, and develop low‐carbon consumption strategies in addition to current infrastructure‐focused action on climate change.