As seas rise, the UN explores a bold plan: Floating cities

A nonprofit called Oceanix is building a prototype floating island as an experimental solution for crowded coastal cities threatened by climate change, the company told the United Nations habitat program Wednesday.

Such buoyant islands would be linked together into floating, self-sustaining cities that rise with sea levels and are built to withstand hurricanes, according to a group of architects, engineers and developers who met at the U.N. headquarters. The prototype will be a small-scale version that could be ready within months, said Marc Collins Chen, an entrepreneur and former French Polynesian politician who founded Oceanix.

Officials at the United Nations welcomed the proposal but have not officially joined the plan to create floating cities. The idea might sound outlandish, but urban coasts are running out of land and becoming increasingly vulnerable as sea levels are projected to rise as much as seven inches by 2030. Ninety percent of the largest global cities are vulnerable to climate change, said U.N. habitat deputy director Victor Kisob. To reclaim shrunken coastlines, Singapore and other seaside megacities already pour sand into the ocean, and sand is quickly becoming a scarce resource.

Amina Mohammed, the U.N. deputy secretary general, said the proposal is more unconventional than approaches the United Nations would have taken even four years ago. “We are trying to adapt,” she said. “We are trying to think ahead.”

The full 4.5-acre floating platforms made of wood and bamboo would be “the basic molecule of a shared urban system,” said Bjarke Ingels of the Bjarke Ingels Group, the architectural firm partnering with Oceanix that is also redesigning the National Mall’s Smithsonian campus.

Each platform would house 300 people. Markets, farms, low-rise apartments and solar panels would stack atop the platforms. The city would grow in a fractal pattern: Six linked platforms, like a hexagon of a honeycomb, would become a village. Six of those villages would be a 10,000-strong town covering 185 acres.

“This is scalable. We would continue to grow this as the demands grow,” Collins Chen said.

Unlike “seasteading,” Silicon Valley’s vision of independent city-states that float outside national rule, the islands proposed by Oceanix would follow local laws. Nor would these be playgrounds for the rich, Collins Chen said. He told the Washington Post he was “not ready to share” projected costs. But he staked his claims of affordability on the cheapness of prefabrication and marine development. Construction costs would stay low, he said, because the floating hexagons can be mass-produced in factories and towed to destination bays.

Squint, and Oceanix’s plans resemble communities that already exist: the houseboats that gather in Sausalito, California; floating apartment complexes in the Netherlands; generations of Tanka fishermen and women who live in China’s southern waterways; the artificial reed islands in Peru’s Lake Titicaca, home to the Uros tribe.

What makes an Oceanix city different, Collins Chen said, is its “integrated vision.” The islands could power and feed themselves. Turbines in the air above the platforms and water below would provide energy, as would solar panels. Rain and desalination systems would provide fresh water. Greenhouses, aeroponic farms and aquatic gardens would provide food. Moorings of Biorock, electrically charged structures that attract minerals and coral, would tether the platforms in place.

The first floating communities would be established at warm coasts, such as those in Southeast Asia. Though architects claimed the platforms could withstand Category 5 hurricanes, ocean engineers suggested the initial cities should be built in calm bays, out of reach from cyclones and pounding waves.

“You have to take small steps,” said Nicholas Makris, who directs the Center for Ocean Engineering at Massachusetts Institute of Technology. “If you’re just trying to get something to work, do it in a sheltered, harbored area.”

Weaving together energy consumption, food production, housing and the marine environment is also a huge challenge.

“The complexity of human systems and ecological systems interacting, we know, is very, very difficult,” cautioned Joseph Stiglitz, the Nobel Prize-winning economist. He cited the unanticipated interactions that caused the 1990s experiment to build a large self-sustaining ecosystem in the Arizona desert, called Biosphere 2, to fail, including cockroaches and microbes that gobbled oxygen. “But the only way we’re going to find out is to actually do these things.”