Contributing author: Sophie Riopel-Gewelt, Assistant Manager, Airport Slot & Capacity Policy
Rapid urbanization
The beginning of the 21st century has been marked by the rise of a global economy and rapid urbanization. The agricultural sector’s productivity improvements in the previous century has led to a rural exodus in many countries and the rapid growth of urban agglomerations. Although cities occupy 0.5% of the world’s surface, they consume over three-quarters of its resources. As much as 55% of the global population lives in cities, compared with 30% in 1950. Globalization, characterized by the increased movement of people, goods, and services between cities and countries, is raising many cities to megacity status.
Megacities refer to very large city metropolitan areas, typically with a population of more than ten million people, and powerful economies. Tokyo, New Delhi, Shanghai, São Paulo, and Mexico City are the world’s largest cities in terms of inhabitants. Each boasts a population in excess of 20 million, and the Greater Tokyo area is home to 37 million inhabitants. As urban populations increase, the land area occupied by cities is increasing at a higher rate.
According to the United Nation’s Department of Economic and Social Affairs, in its 2018 Revision of World Urbanization Prospects, the number of megacities has tripled since 1990; by 2030, 43 urban agglomerations are projected to house at least 10 million inhabitants each. The megacity trend has major implications for airport systems and transport infrastructure.
Constraints of existing airports
As major megacities were growing and expanding outward from the core city center, many airports, built mostly after World War II, were surrounded by residential neighborhoods and became physically constrained over time. Consequently, further expansion of airside infrastructure became difficult or extremely costly, with substantial costs associated with the acquisition of residential properties and compensation schemes.
In the context of robust and consistent growth of air transport demand, the inability to effectively expand the existing infrastructure of airports serving megacities, and their airside components in particular, led to the fast saturation of these airports. The growing number of slot-constrained airports serves as a direct testament to this fact: as of Winter 2020, there are 169 slot-coordinated airports at Level 3. Practically all main airports serving major cities, and certainly the global cities—those that act as primary nodes in the global economic network—are capacity constrained. Twenty-eight out of 33 such airports (85%) are coordinated at Level 3, indicating that their capacity is fully stretched, and that growing demand cannot be fully accommodated. The three additional airports are schedule-facilitated at Level 2, meaning that demand is close to capacity.
Greenfield airports and scarcity of land
When capacity is fully allocated, building new airports capable of accommodating growing air transport demand can represent a viable option. As an example, two recently built major airports—the new Istanbul Airport located in the Arnavutköy district on the European side of the city and Beijing Daxing International Airport located on the border of Beijing and Langfang, Hebei Province—added a combined total of eight new runways into the global airport network, a notable expansion of airport infrastructure at the global level.
Several other airports are also being developed to tackle the capacity crunch, and once again, most of them will be serving rapidly expanding megacities, including Mumbai, Sydney, Chengdu, and Xiamen. Construction of the new airport in Xiamen requires significant reclamation of land: out of 46 square kilometers of the total construction area, 17 square kilometers will be reclaimed from the sea.
Building airports on reclaimed land and artificial islands is not a novelty, but rather a proven way to develop airport infrastructure when conventional terrain is not available. This approach is closely related to the civilizational phenomenon of people concentrating in coastal regions. It is estimated that as much as 40% of the world’s population lives within 100 kilometers of the coast. As such, there is a match between large populations living in megacities located on the coast and an opportunity to create new lands from oceans and seas.
Airports on reclaimed land and artificial islands
Land reclamation is the process of creating new land for oceans, seas, riverbeds or lake beds, and can be achieved with several different methods. Irrespective of the method, it is a costly procedure that has long-standing ecological ramifications that need to be properly mitigated. As such, developing airports on reclaimed land and artificial islands implies substantial costs. Nevertheless, there are several successful airports developed on reclaimed land that brought long-term economic benefits to the local communities as well as the global air transport system, with all the combined costs gradually recovered through user charges.
Japan boasts the highest number of airports developed on artificial islands, with the most notable cases of Osaka-Kansai Airport—the third busiest airport in the country built in 1987–1994, Chubu Centrair International Airport serving Nagoya built in 2000–2005, and Kobe Airport developed in 2000–2006.
Other notable Asian airports developed on artificial terrain, fully or partially, include Incheon International Airport in the Republic of Korea (opened to traffic in 2001), Hong Kong International Airport (in commercial operation since 1998) and Changi Airport in Singapore (land reclamation began in 1975). But this phenomenon is not limited to Asia, as airports on reclaimed land can be found in other parts of the world. For example, parts of Hamad International Airport in Qatar, Nice Côte d’Azur Airport in France, and San Francisco International Airport in the USA were developed on reclaimed land due to the lack of conventional ground.
Costs and benefits
Developing airports on reclaimed land and artificial islands implies substantially higher costs as compared to airports built on conventional grounds. Such projects have significantly longer amortization periods and higher associated risks. Therefore, there is a natural upward pressure in terms of airport user charges. However, it is clear that in the long run, the economic and social benefits of such airports outweigh the costs, subject to proper safeguards with regard to environmental impact and proper mitigation measures. Adding infrastructure will induce costs that will have to be internalized by both users and end-users, but it is the only way of ensuring sustainable growth of air transport from both economic and environmental perspectives.
Developing airports on reclaimed land and artificial islands is one possible way to deal with land scarcity and the looming capacity crunch in the air transport industry, but it may be appropriate only in particular circumstances. Airport developments cannot be pursued if done in isolation from modal connections with railroads and motorways, which represents an additional consideration for such projects.
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