Horizontal urban growth

February 2020: Current urban growth patterns show strong tendencies for outward and horizontal expansion outside East or Southeast Asia. These growth patterns are generally considered to be unsustainable. It highlights the need to incentivise vertical/upward urban growth to deliver low carbon, walkable, resource efficient, and resilient future cities.

Information

Recent studies find that most urban growth is horizontal with increased outward expansion towards suburbs. Increased population numbers, ‘soft’ regulations on land acquisition, zoning, construction, economic development policies, and investment are driving low-rise, outward urban expansion.  Exceptions to this trend can be found on East and Southeast Asia which records a steep rise in construction of high-rise buildings.

Implications and opportunities

Outward patterns of expansion are generally regarded as unsustainable due to their high energy demands and extensive land use. Identifying urban growth areas and how to incentivise upward expansion may aide the development of guidance for future cities. This guidance could prevent the need for ‘retrofitting’ cities and allows for urban growth that is low carbon, walkable, resource efficient, and resilient. These changes would require policy, behaviour and attitude adjustments for land land-use patterns within and around cities to incentivise sustainable urban growth and development.

Limitations

The paper offers insight into current urban growth patterns but only provides limited guidelines for urban planners. Practical application would require adaptation to specific regional contexts.

Sources

Mahtta, R., Mahendra, A., & Seto, K. C. (2019). Building up or spreading out? Typologies of urban growth across 478 cities of 1 million. Environmental Research Letters, 14(12), 124077. doi:10.1088/1748-9326/ab59bf 

UPI. (2019). Cities are expanding outward, not upward – an unsustainable pattern. Retrieved from https://www.upi.com/Science_News/2019/12/20/Cities-are-expanding-outward-not-upward-an-unsustainable-pattern/9621576863225/