CityLoops: Urban Circularity Assessment
A city-scale material-flow and stock accounting method with system-wide indicators, developed within Horizon 2020 CityLoops, Closing the Loop for Urban Material Flows, and adapted from Eurostat's economy-wide framework for urban circularity decisions.
- Period
- 2022–2023
- Status
- Completed research
- Role
- Co-author · Horizon 2020 grant 821033
- Scale
- Five CityLoops pilot cities
Co-author · Horizon 2020 grant 821033
- Named as one of four authors of CityLoops deliverable D4.4, Urban Circularity Assessment Method.
- An evaluation of 29 urban material-flow methods followed by a city-scale adaptation of Eurostat economy-wide material-flow accounting.
- Ten scale indicators and eight circularity indicators, paired with material-flow and bottom-up building-stock accounts.
- A reproducible path from data collection and mass balancing to Sankey diagrams, indicators and a city dashboard, prepared for five pilot cities.
The method estimates and interprets urban material flows and stocks from the best available evidence. It does not claim to audit every tonne moving through a city.
Circular-economy ambitions need a scientifically sound but operable method for understanding how materials enter, accumulate within and leave a city, even when local data are incomplete.
My contribution
At Metabolism of Cities, I co-developed and co-authored CityLoops D4.4 as one of four named authors. The method combined economy-wide material-flow accounting for two reference years with bottom-up building-stock accounting and 18 scale and circularity indicators. It specified Sankey and dashboard outputs for facilitated application in Apeldoorn, Bodø, Mikkeli, Porto and Seville.
Decisions and constraints
Decisions I made
- Adapt Eurostat economy-wide material-flow accounting to the city scale rather than invent a disconnected vocabulary, preserving comparability with national and European statistics.
- Pair two-year material-flow accounts with bottom-up building-stock accounting, because flows alone cannot explain accumulated construction materials or future demolition waste.
- Make mass balancing and downscaling explicit, documented choices when local data are incomplete, then carry the processed evidence into indicators, Sankey diagrams and a dashboard.
Operating constraint
Local flow and stock data vary sharply in availability and quality. The method had to remain scientifically sound and comparable while still being operable by municipal practitioners across five different city contexts.
Claim boundary: The method estimates and interprets urban material flows and stocks from the best available evidence. It does not claim to audit every tonne moving through a city.
What can be checked.
- Named as one of four authors of CityLoops deliverable D4.4, Urban Circularity Assessment Method.
- An evaluation of 29 urban material-flow methods followed by a city-scale adaptation of Eurostat economy-wide material-flow accounting.
- Ten scale indicators and eight circularity indicators, paired with material-flow and bottom-up building-stock accounts.
- A reproducible path from data collection and mass balancing to Sankey diagrams, indicators and a city dashboard, prepared for five pilot cities.
Documents, code and live work.
The case study states the claim. These sources let you inspect the underlying artefact in its original context.