Floating cities as an innovative response to climate change | DW Documentary
Climate change is continuing its advance. Sea levels are set to rise further. How can we respond? We need space - space for water, space for people. And building on water and building beyond the waterfront is a very logical step.
Are floating cities one possible answer to the challenges of climate change? Technically you can do a lot. We have platforms here that can survive hurricanes. Climate friendly and resource-efficient. Is living on water a viable solution? Floating technology, we need it now, at scale, at an affordable rate.
Many people dream of living by the water. And most big cities are located on the coast or by rivers. But the Intergovernmental Panel on Climate Change says the world must brace itself for a one to two-meter rise in sea levels by the year 2100 . Yet our cities continue to expand. Could we soon be living ON the water? It's an idea that architects have been pursuing for decades.
Big architects have played with this theme, but I think the change is now that you go from dream to reality is because of the necessity, because now with the whole urbanization, with climate change, we really need new solutions. Koen Olthuis has committed himself to realizing this vision, and has designed over 300 floating buildings following the example of this hotel from the 1980s. But the idea of a floating neighborhood as an extension of an existing city has yet to really catch on.
We see water as the ideal location where we can grow our cities and make it more safe, but also cheaper to build. If you have to protect your city with all this big walls for maybe 10 or 15 extra meters in the next 100 years, then it's better to already build on top of the water, because that's safer and you can just move up and down with it. Without coastal defenses, one thirds of the Netherlands would be under water.
But it‘s a complex feat. The huge Maesland Barrier protects the Rotterdam region from storm surges. Each gate is equivalent to the Eiffel Tower in terms of weight and size . And Germany, too, has been steadily raising the height of levees over the last few decades.
The danger doesn’t just come from the sea, but rivers, too. It's not just only about space or and or the fact that you can go up and down with the water. There's also flexibility. We really think that our society is changing so rapidly political changes, technical changes and a city has to react to the new situation.
But cities are very slow. If you built a building in stays 50 years or 70 years, you can't change it. But on water, we can react very, very fast Olthuis and his team have designed the world’s first floating city in the Maldives: 5,000 detached homes for 20,000 people, interconnected via roads, canals and bridges.
The ideal situation that we float them out rotate them as a boat, take them out to the main docks and change them and bring them back. Maintenance is more challenging than it would be on land. The bridges will probably need to be repaired every 20 years.
But replacing them is not easy, as the city’s utilities are interconnected and run beneath the roads, bridges and houses. The houses float on pontoons that go down about 1.20 meters into the sea. The price itself of a house to construct a house is maybe a little bit more expensive than building on land because you have your floating foundation. But if you could talk about development cost of these kind of structures, it's less because the price of water. The price of land below water is, of course, less than land in the middle of the city.
So the total development can be much more affordable than building land. And that's necessary because we don't want to build only for the rich. If you really want to solve problems in cities same as in Malé, you have to build affordable housing.
The capital of the Maldives — Malé. With its population of 250,000 people spread across just 8 square kms, it’s bursting at the seams. It’s not unusual for a family of 10 to share a two-room apartment.
The tropical heat is hard to bear without air conditioning. But Malé continues to draw people from the smaller, more remote outlying islands, as it offers better healthcare, education and job opportunities. I think Maldives feels the environment impact most from the world. And we've seen a tsunami and we see the sea level rise every day. There is a need for us to expand the population into small islands. So people started believing or wanting to see an alternative for reclamation or more safer way of expanding life on the sea in the Maldives.
So we believe this is the right time it will be viable and also practical. 15-minutes away from the capital by boat, a private company called Dutch Docklands is building the floating city in a 200-hectare lagoon of a coral reef. The first four homes have just been completed. With a price tag of 250,000 euros for a house with an area of 220 square meters of floorspace, they’re also an option for the islands’ middle classes. Concealed under the wooden houses there is modern technology, such as a gray-water recycling plant for watering the trees. Only time will tell how the sensitive ecosystem of the coral reef responds to the houses‘ mooring, the traffic and altered currents.
Those involved say the city will be environmentally friendly and climate neutral. This is exactly how it looks. We have single storey or two storey houses. We have sand on the street. We will generate electricity from solar or other turbines under the sea, and we will use the seawater to cool systems. Water drawn from the deep sea with a temperature of 7 degrees Celsius is fed through the walls.
By removing the necessity for air conditioning, energy consumption can be reduced by 60%. Wind and wave power cover the other energy needs. This city has everything a city has like football grounds, mosques, offices, everything. That's how when our parents lived, we could go fishing.
We could jump into the water when we want. We don't need to taxi to see the sea, all that kind of thing. So this is more like a village, but used building modern technology. A beautiful, high-tech floating city that responds to the challenges of climate change.
A — seemingly — seductive vision. I’m not very optimistic about how quickly we will be able to adapt. Is the technology like floating technology mature to be able to be used in countries where most of our country is the vast ocean? So it’s an interesting idea, but I am very hesitant to believe that that is the solution for climate change because the real issues that we’re trying to address is reducing our carbon emissions. The Maldives are confronted with the impact of climate change caused primarily by other countries.
Malé no longer has a proper beach. The capital of the island is surrounded by concrete coastal defenses, as it lies only half a meter above sea level. The government already spends 30% of its budget on adapting to climate change. Yet it badly needs that money for schools, hospitals and roads. I don’t want to see a country that is uninhabitable in my lifetime.
And if things go business as usual, that could be a possibility. But I still want to think that there still is time for us to reverse this and save countries like us. At 1.1 degrees today we are experiencing coastal erosion on every single island. Every single island in the Maldives, where Maldivians live, have run out of fresh water. We are increasingly being flooded during the rainy days.
We have more issues with coastal inundation now. And above all, our beautiful reefs are being bleached every year because every year is a warm year now. In Europe, too, we’re feeling the impact of climate change. Our cities are also becoming increasingly built-up. Most average earners here in Amsterdam can’t afford to live in the center. Houseboats have existed in the Netherlands for centuries now.
So why not make greater use of the waterways available? In 2010 a new neighborhood was created 15 minutes from the heart of Amsterdam. It comprises just under 60 homes — some privately-owned, the others affordable rentals. Twelve years ago, Steph’s parents also decided to buy a home here. We didn’t want to be in one of those traditional neighborhoods of newly built houses, with all these houses next to each other with a garden on the same side. And we love sailing and Steph loves the water.
So that was then an easy decision to make to come to this house. Yeah, especially the fact that the boat can be next to your house or in one of the slits down the dock. It’s perfect. it’s not standard and it is with water around. Sacha and Jan felt the city center was just too crowded.
They wanted their son to be able to play alone outdoors. All the neighbors traditionally go for a New Year’s swim together. It’s like a village in the middle of the city. A strong community feeling has grown up over the years in Steigereiland. The houses and jetties rise and fall with the water levels. The lower floors largely already lie below the water line.
So it’s a concrete box which is lifted partly with floating plastic cubes and they put them under to level it because one of the things that you have is that if I have more stuff that my neighbor, I yeah, the house is like this. So that’s one of the reasons why things like we also have a lot of contact with the neighbors is just to, yeah, to discuss things. Because if you put a piano there and you know, they have a problem, so. Not a problem but and at least, you know, something to discuss by the barbecue.
The water quality is good, the fish are happy swimming between the houses. But in strong winds, the floating homes start to rock. Their center of gravity is too high something architects today would plan with greater stability. If you see how big the forces are on these houses, that’s quite extreme. And in all honesty, I sometimes wonder how long this house actually will be here. This house is 10 years old.
I’m not sure if it will get to 100, to be honest. These powerful forces have already caused cracking. Floating homes require more maintenance than those on dry land hence their modular construction, where components can be more easily replaced, recycled, or repaired. How safe is it living on the water? At the Maritime Research Institute in the Netherlands, scientists can simulate extreme weather conditions using wind and wave generators to see what floating solar panels or floating cities can withstand. Olaf Waals knows how much can be done to adapt structures to rough conditions on the open sea. I believe that from what we know from the offshore development that you can do a lot technically speaking like we have platforms here sometimes that survive hurricanes.
So we make in this basin the wind and the waves, and the current associated to a hurricane event, and then we look at the survivability of such a platform. Technically you can do a lot and you have to discuss what do you accept as a cost? Models of floating islands are also tested here. The homes — represented here by blocks — have to stay stable in the water, to prevent their inhabitants getting seasick. You need to find either a flexible connection, then you allow for some motion in a big storm.
that helps in in a big storm that you have a little bit of flexibility to reduce the forces inside the islands. If you connect them rigidly, then it becomes one big pontoon and then it starts to move less. And that can be also beneficial, but at a cost of larger forces inside the island. This floating solar-power facility could make an important contribution to energy production in the future — for floating cities, as well.
The solar panel is, in full scale, 25 meters wide and 7 meters high big enough to let waves through underneath. The idea is for them to be located between offshore wind turbines in the North Sea — where conditions would be a real challenge for a floating city. If you do this in the North Sea, for example, then the forces are still very large. If you do it with mooring chains, you need a lot of mooring chains to really fix the island. We look into hybrid combinations. So you can make, for example, in the North Sea is not as deep, so you can do a reef, an artificial reef, which is basically sand and stones which are mounted to the seabed and they protect from the largest waves.
Right now, it would still be very expensive to anchor floating islands in the North Sea without a barrier. Floating neighborhoods are likewise easier to set up in protected waters. But the development of flexible infrastructure is surging ahead.
South Korea has plans to build an airport spanning the land and sea. We should not wait too long with the research because it also takes time. Like all the big infrastructural developments in the Netherlands, have taken about 40, 50 years to build. And a lot of research was done before they were actually built. The time is now if we want to have the solutions by the year 2100.
Germany still tends to stick to traditional floodwater defense strategies: raising levees and building floodwalls. But in Hamburg that means the River Elbe has become increasingly constrained, in particular by measures taken after the 1962 storm surge. With the difference in water level between high and low tide already more than doubling, the risk of flooding is growing. Professor Antje Stokman thinks giving rivers more space would make waterside-living a safer option in the long-term. The first question is: rethinking the idea of always piling up earth or building more walls.
First of all: how can we build on land so that we give water more room there? We can create floodplains that are built to use space in an amphibian manner. So space can have a dual function to respond to flooding: A park that can be temporarily flooded, but is a park when it’s dry. Houses that are propped up on stilts, or built on mounds. There are many, many strategies that we need to consider more rigorously on land, too! Should we create more floodplain areas that we use more creatively? Floating cafés like this one here by the Elbe are still a rarity despite being easy to build. More and more residential developments involving land reclamation are being created from the IJMeer lake by Amsterdam.
Instead of opting for floating flexibility, Germany and the Netherlands continue to bank on stability. Meanwhile on the Maldives, the coral reef by the capital continues to be filled with sand. Huluhmalé is one of the world’s biggest construction projects designed to combat climate change and create living space.
Alongside the 24-storey skyscrapers, there is also a charming residential neighborhood. The artificial island lies 2 meters above sea level and has been dubbed the “island of hope” by local inhabitants. 80% of the Maldives is not even one meter above sea level. Today it houses more than 100,000 people safely. It doesn’t flood.
It is not affected by coastal swelling. It’s a double-edged sword for us because the impact of reclamation and what it has on our ecosystems that are really fragile, but also what do we do with the rising tides? We don’t have higher ground to go to! The consequences of the project are making themselves felt everywhere: While the corals are dying in part because of piped waste, the construction sediment is also depriving the corals of air. Former school director Ahmed Saeed no longer recognizes the reefs of his childhood reefs that are also the nursery and the feeding ground for numerous fish species. It is all dead coral here. And it used to be a thriving coral formation round here. All this has died now.
Okay there has been coral bleaching. That would have been, but largely due to the dredging especially. I believe the second phase. The dredging must not have been very controlled. In any case: all this area had lots of live fish live coral. But it’s all dead now.
75% of all Maldivian coral reefs are already dead. Extreme heat is mainly responsible. But land reclamation projects have also led to coral deaths. Saeed says that the archipelago’s inhabitants have not been sufficiently informed about the impact. Planners say that floating cities are a gentler intervention in this fragile ecosystem. Floating cities, floating structures, floating technology - we need it now.
We need it now at scale, at an affordable rate. This needs to come to the Maldives now. Time is running out here. The first talks were held with the government in 2008, but the floating-city pilot project continues to face delays.
The floating village would definitely be right now the best solution that we would have. You wouldn’t want to have monstrosities like that where you will probably soon hear about lots of social evils and lots of things happening when people are congested into high-rise places. You see that happening in other countries. Germany isn’t facing such drastic challenges as the Maldives. But population growth in the cities is causing housing problems.
No floating districts are on the agenda yet, however. Does it really make sense to create new city neighborhoods on a big scale on the sea or the rivers? Wouldn’t it be better to reconsider all kinds of land use? We could flood certain areas protected by levees and create floating greenhouses there and think about how to organize high-yield market gardening. Rather than saying we’ll keep that as it is and expand out to the river, too Flooded zones could be used for growing food and not just for human habitation. Or the seas on our doorsteps could help feed floating or conventional cities. Locally based marine aquaculture would help preserve overfished stocks in the wild. Biologist Martina Mühl and her colleagues from the Kiel sea food farm are researching how to create a sustainable circular economy.
If we think ahead into the future and imagine that we will be living on and increasingly with water and operating aquaculture directly on our doorsteps Then I could imagine that we could raise fish, but then we would also have to grow seaweed to make it circular. But we’re talking about big quantities. If we produce one tonne of fish at one spot, then we’d have to produce seven tonnes of mussels at another and algae species, too, in order to remove the nutrients created by the feeding and the excrement of the fish. That would make it circular. One pilot project here involves the growing and processing of seaweed. The sugar kelp does not just help to improve the Baltic’s water quality it’s also rich in proteins, and demand from the food industry is growing.
Seaweed is very healthy. You can call it a staple food. It has a lot of vitamins, minerals, fiber. It can be eaten raw, or boiled and fried I’ll just wash it a bit and then I’m going to eat it. It’s like a tasty, crisp lettuce a bit salty, but very tasty.
Once seeded, the seaweed grows on its own. The mussel farm also benefits the Baltic, because the mussels remove excess nutrients from the seawater. The mussels don’t need feed or fertilizers.
They slurp down whatever’s in the Baltic like a cocktail. They practically eat as they breathe. One single mussel filters about two to three liters an hour. But you’d need 6,000 mussel farms like this one to filter out all the fertilizer run-off washed into the sea by rivers along Schleswig Holstein’s Baltic coastline. And that is hardly practicable.
Closed-circuit systems like this shrimp farm are different. Its autonomous feed supply does not pollute the environment. The shrimps swim in water taken from the Baltic Sea, which is heated up with energy produced by a sewage plant.
In a research project, the used water is so well purified in plant beds that it can be fed back into the Baltic without causing any pollution. One advantage of this system is that it isn’t just the water that circulates, but also the nutrients. It doesn’t matter if you’re in floating cities or in the desert.
What’s important is that you can create new human habitats with this kind of technology. The island capital of the Maldives is not self-sufficient Malé imports almost everything, including most of its fruit and vegetables. A floating city would be just the same in this respect.
Locals live from fishing and tourism — sectors that depend on healthy reefs, which are being destroyed by land reclamation and climate change. Floating cities could be one answer. I think that that we're only at the beginning of these kind of structures on water. You will see many more cities, the 100 biggest cities around the world are next to the water. They will start using the water and that will create worldwide flexibility.
And I think flexibility means that we can react, but also it will be much more sustainable. We use less energy and we can react to any change for the future. Environment minister Aminath Shauna remains skeptical. Can floating cities be realized on a large scale and be ready in time to respond to climate change? Either way: giving up is not an option.
These are all very interesting ways we could possibly adapt to a warmer world. I think we can come together. And the reason why I say this is because we're just emerging from a global pandemic. And in six months we found vaccines. In six months, we unlocked trillions of dollars. So the question is: it's not the lack of money or it's not the lack of technology.
I wholeheartedly believe that the issue here is the lack of political will and failure to understand that the climate crisis is an emergency. Across the world, there are people searching for creative solutions to the dangers posed by climate change — for ways of living more sustainably. Soon, we will see what floating cities have to offer on this front.
The Maldives with its fragile ecosystems could be leading the way.