The evaluation and dynamic monitoring of urban sprawl is essential to the sustainable development of cities and therefore attracts enthusiasm from numerous scholars. This study conducted a thorough review of the literature on the multidimensional and multiscale measurement of urban sprawl. Firstly, it provides a definition based on the common characteristics of urban sprawl to contribute to a relatively uniform definition and judging criteria. Secondly, indicators of growth, morphology, density, land use mixture, and accessibility dimensions are sorted out, as well as dimensions that are not widely operationalized but make sense. Thirdly, the review spotlights single-dimensional measures in large-sample comparative studies and booming comparative studies based on multidimensional measures. Furthermore, another focus lies on different spatiotemporal combinations of temporal and spatial scales for the measurement. Overall, there are large gaps in comparative studies on the multidimensional measurement of urban sprawl under multiple spatiotemporal scales. In particular, few micro-scale studies focus on inner-city units, and few measure urban sprawl at multiple scales simultaneously. Finally, the challenges and future of multidimensional and multiscale measurements are discussed: relativity and uncertainty of sprawl criteria; strong dependence on the choice of spatiotemporal scales; comparability of sprawl measurements that remains to be improved; the necessity of long-term international cooperation on the measurement of urban sprawl at the global and regional levels. The article appeals for more multidimensional and multiscale urban sprawl measurement studies based on multi-case comparisons in the future, especially in the developing context.

There is growing concern about the consequences of future urban expansion on carbon storage as our planet experiences rapid urbanization. While an increasing body of literature was focused on quantifying the carbon storage impact of future urban expansion across the globe, rare attempts were made from the comparative perspective on the same scale, particularly in Central Asia. In this study, Central Asian capitals, namely Ashkhabad, Bishkek, Dushanbe, Nur Sultan, and Tashkent, were used as cases. According to the potential impacts of BRI (Belt and Road Initiative) on urban expansion, baseline development scenario (BDS), cropland protection scenario (CPS), and ecological protection scenario (EPS) were defined. We then simulated the carbon storage impacts of urban expansion from 2019 to 2029 by using Google Earth Engine, the Future Land Use Simulation model, and the Integrated Valuation of Environmental Services and Tradeoffs model. We further explored the drivers for carbon storage impacts of future urban expansion in five capitals. The results reveal that Nur Sultan will experience carbon storage growth from 2019 to 2029 under all scenarios, while Ashkhabad, Bishkek, Dushanbe, and Tashkent will show a decreasing tendency. EPS and CPS will preserve the most carbon storage for Nur Sultan and the other four cities, respectively. The negative impact of future urban expansion on carbon storage will be evident in Ashkhabad, Bishkek, Dushanbe, and Tashkent, which will be relatively inapparent in Nur Sultan. The potential drivers for carbon storage consequences of future urban expansion include agricultural development in Bishkek, Dushanbe, and Tashkent, desert city development in Ashkhabad, and prioritized development of the central city and green development in Nur Sultan. We suggest that future urban development strategies for five capitals should be on the basis of differentiated characteristics and drivers for the carbon storage impacts of future urban expansion.

Although polycentrism is widely promoted by city planners and policymakers as a potential solution for alleviating the sprawl of central urban areas, there is no sufficient empirical evidence to verify the validity of this claim. Our study aims to complement this experience by providing solid evidence on whether polycentric urban structures can mitigate the problem of urban sprawl. In this study, the corresponding evaluation factors are selected from four perspectives: socioeconomic, spatial form and organization, and ecological environment, to measure the performance of Hangzhou’s polycentric spatial development. The results show that the performance in Hangzhou has improved significantly, and the performance improvement is more prominent over the 2010–2020 period. Third, the changing characteristics of the spatial development performance of the city centers show a significant diversity. During the study period, the development of Jiangnan city started early, but the development performance of Xiasha city improved significantly, and the development of Linping city was relatively the weakest. Fourth, socioeconomic and urban spatial organization are the main factors causing the temporal stage and spatial variability of the performance in Hangzhou. It can be seen that market-driven endogenous factors are more conducive to improving spatial development performance than government-led exogenous factors.

The spatial mismatch between affordable housing neighborhoods and public services/facilities significantly reduces the well-being of low-income dwellers, which has risen to a typical issue of spatial injustice. Previous studies on accessibility evaluation most focus on a single type of service, lacking empirical studies exploring the integrated spatial accessibility of multiple services for low-income residents. Taking Harbin City in northeast China as an example, this study assessed the spatial accessibility of transit, education, healthcare, shopping, and recreation facilities for affordable housing neighborhoods, using the Gaussian-based 2SFCA method. The pattern of accessibility for each type of facility in Harbin showed obvious spatial differentiation between the urban core and the city periphery, for both affordable housing neighborhoods and other neighborhoods. The sample household survey indicated that low-income households who were generally characterized as elderly, less-educated, under-employed or unemployed had extremely restricted and passive residence choices. In comparison to non-low-income households, the spatial accessibility of higher-level facilities for low-income households was relatively poorer. Particularly, affordable housing neighborhoods had much lower accessibility of subway stations, though more than 97% of low-income respondents living in affordable housing neighborhoods chose to solve the daily trip demand by taking a bus or the subway. With respect to equity-oriented urban planning, more importance should be attached to the spatial accessibility of public services and facilities when planning affordable housing projects for low-income households.