07/09/2020 – Sustainability Series / Floating Cities / Climate Change / Overcrowding / Asia
Cities on the sea: A novel response to climate change
Helping to tackle the effects of climate change whilst also offering a solution to overcrowding in coastal cities, the concept of ‘water-based communities’ could provide a novel way forward for city planners.
Since 1880, average sea levels have swelled by eight inches (23 centimetres), with about three of those inches gained in the last 25 years alone. And annually, the sea rises by a further .13 inches (3.22mm). This loss of land is already exposing the vulnerability of communities across the world, and this watery encroachment is only set to continue in the years ahead.
According to new research published by scientific journal Nature Communication, 200 million people in the world will live below the sea level line by 2100, with an additional 160 million set to be impacted by higher annual flooding due to rising ocean levels. Of the 200-million directly affected by rising sea levels, researchers estimate that 70 per cent will live in just eight countries in Asia – China, Bangladesh, India, Vietnam, Indonesia, Thailand, the Philippines and Japan.
At the same time, amidst an accelerating urbanisation trend, overcrowding is becoming an ever more difficult challenge for city planners the world over, as they strive to improve living conditions in congested urban centres. Sadly, the countries most exposed to rising sea levels in the years ahead are often also home to the world’s most densely populated urban areas – cities such as Aligarth, Vijayawada and Mumbai in India, and Chittagong and Dhaka in Bangladesh.
In response to the potentially devastating impact of climate change through erosion and flooding, and to combat overcrowding and poor living conditions, policy-makers and engineers alike are looking into how water-based communities could be developed. Located about one kilometre from land in the shallow waters of host nations, these floating settlements could offer a clean slate to rethink how people build, live, work, and play.
Floating the idea
“Floating cities sounds like a crazy idea, but they could lead to all sorts of possibilities if done in the right way,” remarked Victor Kisob, Deputy Executive Director of UN-Habitat, the UN’s programme for human settlements and sustainable urban development, speaking as part of a panel discussion at the World Urban Forum in Abu Dhabi earlier this year. “In 2019, the United Nations pushed forward a discussion on this topic, and we are keen to come up with real solutions for these cities.”
One organisation making waves in this regard is non-profit organisation Oceanix, which, in support of the UN-Habitat’s New Urban Agenda, has designed a concept for the world’s first sustainable floating community.
Marc Collins Chen, Chief Operating Officer at Oceanix, said the city would produce its own power and heat using renewable sources such as sunlight, wind and waves. Water would be harvested from rain generation and vapour distillation technologies.
“I often get asked if these settlements would be robust against tsunamis, hurricanes and other severe weather extremities,” he said. “We’re actually working with MIT’s Centre for Ocean Engineering to see how these modular structures can sustain category five weather conditions. It’s a design issue – it’s about building differently.” Oceanix has also stated that its first cities would be calibrated for the most vulnerable tropical and sub-tropical regions around the globe.
The evolution of water communities
Made up of floating, modular platforms that are moored to the ocean floor, the Oceanix concept allows for the evolution of a community – from a neighbourhood of 300 residents to a city of 10,000, “with the possibility of scaling indefinitely”, the firm said.
Low-rise buildings – distributed to balance weight evenly at 4–7 storeys – would help create a low centre of gravity and resistance to wind.
The platforms that make up the modules are designed with net-zero energy production in mind, with an abundance of clean renewable energy from the sun, wind, waves and current harnessed to power and cool the neighbourhood. Combined, such power sources would generate 30kWh per person living on the floating city, said Oceanix.
‘Fresh water autonomy’ is another key feature of the design, with the platform systems collecting water from rain (via roof collection), humid air (via dehumidifiers), and the sea (via renewable desalination). Grey water would be captured and recycled for reuse – and none of it would be released into the ocean.
“We need to ensure very little waste is coming out of a structure like this to make it sustainable,” stressed UN-Habitat’s Mr Kisob. And indeed, in Oceanix’s proposed floating city concept, materials would be managed in circular loops to avoid the creation of waste. Packaging would be reusable, domestic items would be shared and fixed at an Exchange Hub, and food waste would be collected via pneumatic tubes and converted into both energy and compost for food production within the community.
Organic produce would be effectively grown within the city using aeroponic and aquaponic systems, complemented by traditional outdoor farms and greenhouses. Meanwhile, what Oceanix has called ‘biorock reefs’ arrayed around the platforms would both dissipate wave energy and provide intensive whole-ecosystem mariculture seafood production. Furthermore, seaweed, oyster, mussel, scallop and clam arrays beneath the platforms would clean the water and accelerate ecosystem regeneration.
Regarding transportation around the community, Oceanix’s floating city concept relies upon mixed modes of sustainable electric (including hydrofoil water taxis, catamarans, ferries, and passenger submersibles) and connected mobility (car shares, delivery boats, cars, and drones, and UAVs). An eight-mile flexible roadway per platform (i.e., per 300-strong community) would be shared by small EVs, autonomous delivery robots, bikes and pedestrians, while cars and bikes would be parked out underneath the platform when not in use, in order to reduce space demands.
Shoring up support
As experts grapple with the prospect of coastal communities being flooded by rising sea levels, the world’s first self-sustaining floating city could become a reality within the next decade, hopes UN-Habitat’s Victor Kisob. “The next step would be to design a prototype with partners from the private sector that could be tried and tested,” he said, adding that establishing a “brain trust” to increase knowledge on the science that would guide such an initiative was crucial.
While the technology to build these floating cities exists today, Mr Collins Chen of Oceanix says that hurdles remain ahead of their realisation – not least in bringing all the required technologies together in an affordable way. “If we design something that’s unaffordable, it defeats the purpose of being sustainable. These cities are for the masses, not the few,” he points out.
Equally vital would be the “political will” and finding the right city to host the prototype. “Cities have relied on water throughout history, so the right partner would be a city or government that recognises the role of the ocean in a positive way,” he pointed out. “We are looking to partner with a country that shows recognition of the global issues around urbanisation and a strong leadership that is willing to think outside of the box to effect change.”
Without doubt, floating communities offer a radical rethink of what a city should look like and how it should function – yet to reduce the threat of human displacement and permanent infrastructure damage, such an overhaul of the concept may well be what is required for the world to create more resilient and sustainable cities. Given the chance, ‘offshore’ properties could prove a hit in terms of achieving self-sufficiency and improved quality of life for its citizens. In turn, today’s sea-shore could quite possibly become tomorrow’s prime real estate.