Future of development: Urban agglomerations and Syphon Effect

How can we balance rapid urban growth with sustainability?

Urban development symbolises socioeconomic growth and human progress. In recent decades, worldwide urbanisation has garnered significant attention due to a substantial increase in urban populations. In 1980, the global proportion of the urban population was just 39%, which surged to 50% by 2008, equaling the rural population. Currently, the urban population stands at 57%, and projections indicate that by 2050, urban population figures will reach 70%.

The growth of the urban population and the urban syphon effect (where large cities attract more talent and resources) go hand in hand. Large cities offer superior healthcare, better education, and abundant job opportunities, which draw more human resources. This influx of talent to large cities further accelerates urban development, strengthening the urban syphon effect.

The syphon effect is evident in numerous global metropolises. Examples include China’s Beijing and Shanghai, the UK’s London, France’s Paris, the US’s New York and Los Angeles, as well as Japan’s Tokyo, and so on. Big cities attract human resources and economic investment from their surrounding areas and other countries, propelling their rapid development. However, prolonged syphon effects may strain the core cities’ ecological capacity and hinder the growth of smaller neighbouring towns.

Establishment and development of urban agglomerations

To avoid the imbalanced development caused by the syphon effect of large cities, numerous countries have proposed the idea of urban agglomeration development. This policy entails multiple cities coordinating their growth, which can effectively alleviate the population pressure on core urban areas. As large cities within urban agglomerations spur development in their peripheries, smaller towns can also access better resources, helping them retain talent.

Credit. Midjourney

There are multiple mega-urban agglomerations worldwide, such as the Great Lakes Urban Agglomeration in North America, the Yangtze River Delta Urban Agglomeration in China and the British Urban Agglomeration. The formation of urban agglomerations has diminished administrative constraints between neighbouring cities, enhancing opportunities for cooperation. These urban agglomerations exhibit active internal resource flows, such as population migration, goods transportation, fund transfers, information exchange, etc.

After long-period resource interactions, various cities within urban agglomerations exhibit distinct levels of sustainability. Cooperation between cities has promoted regional economic development, yet it has also led to issues of uneven urban growth. Once two cities establish a long-term cooperative relationship, their connections with other surrounding cities may weaken, which is detrimental to balanced urban development.

Sustainability of urban agglomeration 

In order to facilitate comprehensive and well-rounded urban development, The United Nations introduced 17 Sustainable Development Goals (SDGs) in 2015, covering various aspects, including social, economic, and environmental dimensions. Many countries have caused ecological and environmental damage to prioritise economic development, which is undoubtedly catastrophic for the entire planet. Therefore, SDGs proposed by the United Nations point out the direction for national development. While promoting economic development, attention should be paid to the coordination of climate, environment, ecology, resources, and other aspects. Urban agglomerations are an integral part of a country, and the sustainable development of urban agglomerations directly affects the sustainability of a country. Therefore, solving the sustainable development problem of urban agglomerations is an important issue that countries will face in the future.

Future of urban agglomeration development

There is no strict limit on the number of cities in urban agglomerations. The Great Lakes Urban Agglomeration in North America has more than 100 cities, while the Yangtze River Delta Urban Agglomeration in China has only 27 cities. Is the number of cities in an urban agglomeration greater or lessr? Whether a single large urban agglomeration or several small cities were a superior means of integrated and coordinated development for urban agglomerations, This is a problem that needs to be faced and solved in urban agglomeration development. Perhaps government managers hope to connect their cities with big cities, believing that the more cities in an urban agglomeration, the better. Ecologists believe the local ecological region should determine the number of cities in urban agglomerations. Collaborative management of large areas of ecological land, such as forests, rivers, and wetlands across multiple cities, is more conducive to ecological protection. Economists, from an economic perspective, believe that urban agglomerations formed by economic complementarity among cities are the most meaningful. 

Whether the number of cities is large or small, the ultimate goal is to achieve sustainable development. In addition, sustainability science can provide an effective scientific model for determining the scale of urban agglomeration. The SDG scores can be used to assess the development strengths and weaknesses of cities. By considering the geographical locations of these cities, the potential cooperative relationships could be explored to determine the most suitable collaboration approach. For instance, if City A faces deficiencies in food production and is situated near City B, a significant agricultural hub, establishing a long-term food import-export agreement between the two cities can help address City A’s food scarcity issues and promote balanced development. Furthermore, once cities A and B are united, entity C will possess a new set of SDG scores. On this basis, considering the sustainability of Entity C compared to other cities, additional avenues for cooperation can be explored.

In summary, one of the drawbacks of urban agglomeration development stems from a lack of systematic and scientifically defined combinations of cities, resulting in imbalances in their progress. To overcome this challenge and ensure sustainable development, it is crucial to establish the appropriate scale of urban agglomerations. This also constitutes a significant concern for the future of urban agglomeration development that requires attention.

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Journal Reference

Meng, Q., Zhang, Z., Fei, X., Guo, Y., & Xiao, R. (2023). Scale optimization of urban agglomerations based on the connection strength between cities under the framework of sustainable development. Environment, Development and Sustainability, 1-24. https://doi.org/10.1080/23738871.2022.2057865

Rui Xiao is an Associate Professor and a doctoral supervisor at the School of Remote Sensing and Information Engineering, Wuhan University, China. He is also a visiting scholar at Cornell University and Arizona State University in the USA. His work has been published in world-leading journals in urban and environmental studies. Rui's research interests encompass urban sustainable development, ecological environmental changes, optimal land-use planning, and the water-food-ecology nexus. He has published multiple academic papers, and the citation frequency of his papers is more than 3000.

Hanyu Yin is a master's candidate at the School of Remote Sensing Information Engineering, Wuhan University. His research interests include urban computing and sustainable development in urban agglomerations. His specific research involves comparing 17 sustainable development goals within urban agglomerations, exploring collaborative models within cities, and analyzing the ecological and environmental changes resulting from urbanization processes. These studies aim to offer government officials and urban planners ideas and solutions for sustainable urban development.