Spatio-temporal metabolic rifts in urban construction material circularity
Bibliographic record
Abstract
Global demand for resources currently exceeds Earth's carrying capacity. Representing a majority of global resource use, and associated environmental burdens, cities must address overconsumption by improving material circularity. This work explores the potential for the construction sector to reduce the indirect environmental impacts connected to increasing material circularity in the coming years. An urban metabolism simulation tool based on system dynamics and life cycle thinking is deployed to estimate the effects of circularization on environmental impacts. Illustrating with a case study of Montréal (Canada), impacts are disaggregated to supplier nations, provinces and territories. As material circularity increases over time, impacts decrease in the sub-national and international regions, but increase in the city due to the activities associated with second life valorisation. In supplier regions, especially Brazil, Mexico, and Norway, environmental impacts decrease between 80 and 100 % in all 18 impact categories by 2050. However, these decreases are found to be shared mostly among Canada's more developed trading partners, revealing an environmental justice risk for circular materiality to disproportionally favour the better-off. Five of the 18 categories did not undergo spatial burden-shifting, improving at all spatial levels in the assessment, while 13 showed decreased environmental impacts remotely at the expense of increased impacts within Montréal.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".