What are the challenges for a floating city?

4 minutes of reading

What if tomorrow we lived in cities that floated on the sea? It’s an idea that is gaining ground through a UN-supported initiative. But is it a maritime pipe dream?

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Living on the water is the stuff of dreams. We think of those houses on stilts in the tropics, or maybe carefree holidays or even the harsh lives of traditional fishermen. There have been numerous projects involving floating utopias: in the 1960s the Japanese Metabolist architects, led by Kenzō Tange, envisaged living in sprawling maritime cities in Tokyo Bay. More recently, the French architect Vincent Callebaut designed a project for a mobile floating village, with overhead wind turbines to make it energy self-sufficient. There have been numerous plans to build floating recreational cities, somewhere between a giant cruise ship and a mobile version of a luxury seaside resort. Some Silicon Valley billionaires, tempted to live in seclusion in international waters to avoid paying taxes, even gave some thought to financing the construction of floating cities where they could set up their businesses on the high seas.

But building on water is already a reality: in the Netherlands, where houses float on fresh water, recently joined by a floating farm near Rotterdam; in Copenhagen, where student accommodation is tied up to the port; in Paris, where the Joséphine Baker pool floats on the Seine. In Singapore, there is a real floating stage in the very centre of the city. These initiatives aim first and foremost to exploit new building potential in places where land is limited, but they can also be seen as technical experiments that help us to prepare for the consequences of climate change. Bridges, solar panels, wind turbines and runways are just some of the many infrastructures that have already seen floating versions take shape, not to mention floating port and tunnel projects.

Today’s technology means that there are now no obstacles to building entire floating cities. The designers of the Oceanix City project offer neighbourhoods for 300 inhabitants, built on floating modules that are energy self-sufficient and produce their own drinking water. Most importantly, they are designing a self-sufficient food production project, through underwater aquaponic farms, located immediately below floating platforms which support four- to seven-storey buildings. The idea is to create new neighbourhoods connected to city centres and designed to promote affordable housing in the world’s most populous coastal megacities.


More and more urban dwellers live on the coast

The UN Human Settlements Programme, UN-Habitat, projects that city populations will continue to grow, reaching 60% of the world’s population in 2030.[1] Urban coastal zones in emerging countries are the most affected: of the 10 world cities that will pass the 10 million inhabitant mark in the coming years, 9 are coastal. This new urban population is particularly exposed to natural disasters, including flooding and periods of coastal inundation which are becoming more frequent with climate change. For example, thousands of disadvantaged people in Nigeria live in Lagos in floating shantytowns and we have all been affected recently by images of Venice beneath the waves and the floods in the south of France. But disaster can take on greater proportions. For example, Indonesia has decided to build a new dry capital while Jakarta, with its 10 million inhabitants, gradually sinks below sea level at a rate of up to 25 centimetres per year.

Alongside this climate problem there is also a housing access problem. According to McKinsey, one third of the world’s population experiences problems when trying to access housing in cities, and the lack of land for building is the biggest obstacle to the development of affordable housing. Some coastal megacities have found a way around this by building higher city-centre buildings while others, such as Hong Kong, are already among the most densely populated cities in the world. Most Asian megacities are making massive investments in offshore expansion in order to create new land for building close to the centre but this brings substantial investment costs and a hefty ecological impact.


Are floating cities a future solution?

It is against this background that the entrepreneur Marc Collins Chen, CEO of Oceanix, has relaunched the idea of building floating cities, alongside the BIG agency’s Danish architect Bjarke Ingels. On 3 April, the UN in New York held a round table on floating cities, led by Amina Mohammed, Deputy Secretary-General of the United Nations. The MIT Centre for Ocean Engineering joined the table to promote the possibility of building cities on water to combat the problem of affordable housing, while protecting residents from the rise in sea level. Floating habitats are therefore no longer the dream of a few libertarian billionaires that they were a few years ago. Nowadays it is an initiative that receives political support, and a prototype is due to be trialled in the coming years.

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Are there risks involved?

However, the construction of floating cities raises other issues, primarily ecological ones. There are those, for example, who point out that the construction of floating cities produces an immediate response to the problem of climate change, without however offering a long-term solution to this problem; the effects of these floating megastructures on marine ecosystems are also ignored. The construction of these marine cities also depletes natural resources, although presumably much less so than offshore expansion in Asian countries, which are very resource-intensive. Should it be seen as a new form of urban sprawl on water?

From a practical point of view, the day-to-day functioning of these floating cities raises questions. How will these floating cities be connected to existing mainland cities? And how will our lifestyles adapt to living on water? A resident of Amsterdam, whose floating home rocks during windy weather, tells Le Monde, “Our lights regularly sway back and forth.[4] We have also had to counterbalance our furniture weight against that of our neighbours!” We need to transition to a way of living that is more open to the unexpected.

In addition to these ecological and practical questions, there is also the social aspect: how do we build affordable housing in these floating cities? This is a key economic challenge that the Oceanix City model hopes to address. Some of the previously envisaged floating cities were aimed at an elite who were the only ones who could afford them. Current projects will have to avoid this pitfall, otherwise they will become floating ghettos for billionaires, thus deepening inequality in the world.

Research into floating cities continues. Let us make sure that it is ecologically responsible and for the benefit of all.