UNIVERSITY OF HONG KONG
FACULTY OF ARCHITECTURE

09 Hypercity

Director/Producer: Tom COZENS
Music: Tom COZENS
Script: Tom COZENS and Professor Chris WEBSTER

Executive Producers: Professor Chris WEBSTER and Dr Eric SCHULDENFREI
Assistant Producer: Alex TAIT
Production Assistant: Winnie YEUNG
Editor: Nick BRIER

Academic Contributor: Professor Chris WEBSTER
Actors: Xianwei LONG and Yi SUN

As cities grow in size, their so-called externalities – the third-party good and bad spill-over effects from private transactions – grow at a faster rate than population. Crime and traffic congestion, income and patents all tend to grow more rapidly than city population, displaying super-linear returns to scale.  When a city doubles, these products of human interaction tend to rise by approximately 115%. By contrast, the infrastructure that supports cities tends to display sub-linear returns to scale. Doubling of city size requires only roughly 85% more road space, water pipes and electricity lines. Large cities are cheaper to build than smaller cities but are more economically productive. Large cities are also more productive of social ills and some of these may cancel out the positive social gains from greater economic productivity. Since economic gains are captured individually via wages and wealth, but social ills are shared (a tragedy of the commons), this explains the relentless rise of the megacity. That relentless rise means that new forms of regulation and control will be needed. Will the 21st century’s polycentric megacities of 50-100M people require more of the same kind of control systems as the 500K-1M megacities of the 20th century? Will it turn out that smart city governance technology has arrived just at the right time – delivering new kinds of automated control systems? Variable traffic speed-limits adjusted in real time can now keep flows moving at optimal rates to avoid the traffic stop-start ‘waving’ that plagued urban driving for half a century. Construction waste and air and water pollution monitoring, source-tracing, pricing and optimisation systems are being developed to support cap-and-trade markets that turn urban externalities into tradable commodities. If smart city tech can solve many of the ‘curses’ of the city, will cities get even larger? What is wrong with ‘large’ if we can all live together happily?

Chris Webster, HKU, 2021

Featured HKUrbanLabs:

iLab
Centre of Urban Studies and Urban Planning
Fabrication and Material Technologies Lab
Ronald Coase Centre for Property Rights Research

Readings:

Chau, K. W., & Wong, S. K. (2014). Externalities of urban renewal: A real option perspective. The Journal of Real Estate Finance and Economics, 48(3), 546-560. https://doi.org/10.1007/s11146-013-9418-z

Li, X., & Nam, K.-M. (2017). One country, two “urban” systems: Focusing on bimodality in China’s city-size distribution. The Annals of Regional Science, 59(2), 427-452. https://doi.org/10.1007/s00168-017-0838-1

Liu, X., Derudder, B., & Wu, K. (2016). Measuring polycentric urban development in China: An intercity transportation network perspective. Regional Studies, 50(8), 1302-1315. https://doi.org/10.1080/00343404.2015.1004535

Ng, E., Yuan, C., Chen, L., Ren, C., & Fung, J. C. H. (2011). Improving the wind environment in high-density cities by understanding urban morphology and surface roughness: A study in Hong Kong. Landscape and Urban Planning, 101(1), 59-74. https://doi.org/10.1016/j.landurbplan.2011.01.004

Sarkar, C., Webster, C., & Gallacher, J. (2017). Association between adiposity outcomes and residential density: A full-data, cross-sectional analysis of 41Y 562 UK Biobank adult participants. The Lancet Planetary Health, 1(7), e277-e288. https://doi.org/10.1016/S2542-5196(17)30119-5

Wu, J., Wang, Z., Li, W., & Peng, J. (2013). Exploring factors affecting the relationship between light consumption and GDP based on DMSP/OLS nighttime satellite imagery. Remote Sensing of Environment, 134, 111–119. https://doi.org/10.1016/j.rse.2013.03.001

Zhu, T. (2011). Building big, with no regret. AA Files, (63), 104-110. https://doi.org/10.1163/9781684171170_003

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