Scaling and Population Loss in Mexican Urban Centres

Despite its pervasive implications, many cities worldwide continue to expand in a fragmented, horizontal manner. We analyse urban growth dynamics in 69 Mexican metropolitan areas from 1990 to 2020 using census data, developing a model of urban form change based on population size, density, and spatial configuration. We employ a radial probability density function and the urban expansion factor to create a framework for comparing urban expansion over time and across different regions. Over the past three decades, Mexico’s urban population has nearly doubled. However, populations have shifted outward, resulting in a decline of 2.5 million residents in central areas. Our analysis shows that distances from the city centre have increased by 28% on average, driven by population losses in central zones combined with growth in peripheral regions.

💡 Research Summary

The paper investigates urban growth and population redistribution in 69 Mexican metropolitan areas over the three‑decade period 1990‑2020. Using census data disaggregated onto a 470 × 470 m grid, the authors compute radial population densities (σ) in 100 m concentric rings and average densities (¯σ) within disks of increasing radius. To enable meaningful comparisons across cities of vastly different sizes, they introduce a “remoteness” scaling factor r = 1000·s/√P, where s is the physical distance from the historical city centre and P is the city’s total population. This transforms each city into an equivalent one‑million‑inhabitant reference, preserving the original density distribution while normalising spatial extent.

Cities are then divided into four remoteness zones: central (r < 3), intermediate (3 ≤ r < 5), distant (5 ≤ r < 9.3), and peri‑urban (r > 9.3). The analysis reveals that, despite a national urban population increase of 54 % (from 81.7 million to 126 million), all metropolitan areas experienced a net loss of about 2.5 million residents in their central zones. Conversely, the intermediate, distant, and peri‑urban zones gained 5.8 million, 16.1 million, and 11.7 million people respectively. The share of urban residents living within the central zone fell dramatically from roughly 40 % in 1990 to 22 % in 2020, and the average distance to the city centre (or remoteness) grew by 28 %.

The change in radial density Δσ(s) = σ(s,2020) − σ(s,1990) shows a clear dependence on distance: negative values dominate for r ≈ 2‑4, indicating central density loss, while positive values appear beyond this range, reflecting peripheral densification. This pattern holds across all examined cities, suggesting a systematic “core abandonment” phenomenon.

To interpret these dynamics, the authors propose a two‑component model separating extensive and intensive effects. The extensive component scales with overall population size and captures the agglomeration‑driven outward expansion. The intensive component reflects size‑independent factors such as housing policies, infrastructure investments, and institutional capacity. By quantifying both, the model demonstrates that Mexican urban growth is not merely a function of demographic increase but also of policy‑driven processes that accelerate peripheral growth and central decline.

Overall, the study concludes that Mexican metropolitan areas are undergoing a shift from traditional high‑density cores toward a more dispersed, suburbanised form—an urban sprawl characterized by declining central densities and expanding peripheral populations. The findings have important implications for transportation planning, service provision, and sustainability policies, emphasizing the need for integrated strategies that both revitalize city centres and manage peripheral expansion.