Analyzing Scaling Laws Beyond City Boundaries Reveals Substantial Environmental Benefits of Dense Settlements
42 Pages Posted: 16 Dec 2024
Date Written: December 05, 2024
Abstract
Urban scaling laws have been proposed to explain how, as populations of cities grow, per-capita infrastructure demand decreases while per-capita socio-economic activity increases relatively. However, previous work deriving these ‘universal’ laws used artificial administrative urban boundaries and ignored the internal structure of cities. It is therefore unclear, whether these scaling effects result from population growth or densification, and how universal these laws are across the entire rural-urban settlement continuum.
We here leverage novel high-resolution remote sensing derived maps to quantitatively assess density-based scaling relations for buildings and mobility infrastructure across the contiguous United States (CONUS), overcoming the conventional one-city-one-value approach. Using 1 km grid cells, we examine scaling relationships between population density and 18 indicators for buildings and mobility infrastructure, covering material stocks, service provisioning, and operational GHG emissions. Results show that residential buildings (building footprint, floor area, materials) exhibit moderate sub-linear scaling (scaling exponents β: 0.82-0.89), while non-residential buildings and mobility infrastructure (area, materials) have pronounced sub-linear scaling relationships (β: 0.42-0.74). While scaling relationships show some variability, they generally hold across grid cell aggregations, outlier removal options, and regions. Scenarios assuming accommodation of additional future inhabitants in dense urban and suburban areas reveal that demand for new buildings and infrastructure could be reduced by 19.6 and 16.2 Gt of materials, and operational GHG emissions by 330 and 350 MtCO2, respectively, compared to a business-as-usual trajectory maintaining current population densities across the settlement continuum. Densification is therefore confirmed as crucial strategy for climate change mitigation and sustainable resource use.
Keywords: scaling laws, population density, infrastructure, buildings, material stocks, greenhouse gas (GHG) emissions
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