Can Man-Made Floating Cities Save the Ocean?

The Seasteading Floating City Project by Joe Quirk
(this article first appeared in the World Ocean Journal, Oct. 2015)

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Biomimicry is the means by which cities could be based on nature’s structures. This city design (by Vincent Callebaut) is based on the lily pad, which is solar-powered and environmentally restorative.

What if the way to save the ocean is to live on it?

The solution to restore our abused oceans may be counterintuitive. A diverse international community of marine biologists, nautical engineers, aquaculture farmers, maritime attorneys, security personnel, investors, environmentalists, and artists has initiated the seasteading movement, a campaign to homestead the high seas by building buoyant cities that float on the ocean.

You might well ask: Why on earth?

Start from the realization that we don’t live on Planet Earth. We live on Planet Ocean. Planet Ocean is more than twice the size of Planet Earth, and many believe we can save Planet Earth by building cities on Planet Ocean.

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FMI about the Seasteading architectural design contest visit

What if every baby born added a small improvement to the ocean environment? What if the wealthier each baby got, the healthier the oceans became? What if accelerating the rate by which the poorest billion people became prosperous could fuel a mass restoration of the ocean? What if cities built in the twenty-first century could serve as a giant clean-up system for the planet? What if the increase in human population could restore the seas instead of polluting them?

The solution is cyclical metabolism. It’s not a new idea. The ocean and has been doing it for billions of years. A quarter of the carbon dioxide we produce is absorbed by the ocean, almost half the oxygen we breathe comes from the ocean, a large amount of the nutrients modern people consume have their origins in the ocean, and every molecule of water that passes through our bodies spends 98% of its time in the ocean. The ocean powers all life, and it can power all civilization. Here’s how:

Ricardo Radulovich, an agricultural water scientist from Costa Rica, plans to transform greenhouse gas and ocean pollution into food for the poor. His plan is massive seaweed farms which can transform the nutrient and carbon pollution humanity has dumped into the oceans into edible sea crops. The more carbon seaweed pulls out of the ocean, the more carbon the ocean pulls out of the atmosphere. Life utilizes the carbon cycle, and so should civilization.

Seaweeds are some of the most productive and nutritious plants in the world, representing three large groups, red, brown, and green, and at least 11,500 species, containing a much healthier nutritive profile than wheat, corn or soy, and an astounding diversity of varieties. Most people don’t know they eat various forms of algae all day — from the creamer in your morning coffee, to the make-up or sunscreen you put on your skin, to the toothpaste that cleans your mouth, to the medications or vitamins you take as tablets or capsules, algae permeates your body. Marine algae is in ice cream, milk, sausages, salad dressings, muffins, and mayonnaise. It’s even in baby formula and pet food.

Cyclical metabolism can clean the seas. Humans eat food and create sewage. Algae eat sewage and create food humans eat. Why are we ignoring this symbiosis? Ricardo and others propose that massive algae farms could be stationed near polluted coastal waters all over the world to gobble up the products of untreated sewage, creating biomass we can use to feed and fuel the world. As algae farms profited and scaled up in size, wildlife would return to the purified waters.

Ocean farming wouldn’t just restore the oceans. It would restore the land.

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FMI about Seasteading Floating Sea Farms:

Seventy of the worlds’ available fresh water is used for agriculture, and roughly a third of all land is used for agriculture. Algae farms require no fresh water, soil, or pesticides, and on the ocean they can expand to any size. Unlike land crops, algae grow and harvest year-round. Algae don’t suffer from droughts or floods. They grow in a stable, year-round environment. All they need to ramp up to colossal proportions is carbon pollution and nutrient pollution, two things agriculture is producing in colossal quantities.

Corn and cow farms produce unhealthy food and pollute the oceans. Algae and fish farms produce healthy food and clean the oceans. The transition from agriculture to aquaculture will transform our corn farms into algae farms, and our cow farms into fish farms. This will free up the fresh water for the world’s poor, and we can give the world’s farmland back to the song birds.
“There is the possibility of producing seaweeds, fish, shrimp, oysters, and many other products, directly at sea, without needing a single drop of fresh water,” says Ricardo Radulovich. “So the possibilities are many, and we are barely beginning to exploit them. The area available to produce at sea is enormous. The amount of water available to produce at seas is enormous. So we shouldn’t be at all worried that we’re going to run out food, or we’re going to run out of water. Of course if we keep producing only on land, that may happen. It is happening already. But the sea represents the next agricultural landscape. We have to change our frame of mind.”

By mixing seaweed flour with wheat flour, Ricardo is working to end malnutrition in the developing world. The Bill and Melinda Gates Foundation helped Ricardo found the Sea Gardens Project, which teaches the poor how to grow floating farms which can be scaled up to any size. Soon Ricardo hopes to demonstrate how microcosms can work profitably on an industrial scale. Algae farms will continue to scale up in size, detach, move out, and lay the agricultural foundation for an ocean city.

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Imagine a city built in a lifeless desert that transforms the wasteland into a garden. Imagine if this city could provide an endlessly renewable abundance of food, fuel and fresh water that would not have existed had the city not been built. All the desert residents have to do to access this bounty is to reach a thousand feet below the desert surface.

Such a city-sized horn-of-plenty sounds like something out of a fantasy. Yet the technology is old news. It was demonstrated during the Carter Administration, yet the innovation was abandoned because unsustainable fossil fuels and agriculture were cheaper. Today, as demand for energy, food, and water increases, national governments and venerable corporations are already working to build these energy powerhouses that could support cities.

To understand, imagine this desert city not fixed on land, but floating on the ocean. Such floating cities could provide a virtually endless fountain of food, fuel, and fresh water.

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The ocean is the largest solar panel in the world. Lockheed Martin estimates that each day the tropical oceans absorb three times the amount of energy that the world currently consumes. Incredibly, the ocean’s stored energy can be tapped. We each use a form of this technology every day. Consider your refrigerator, air conditioner, or the engine in your car. Much of the energy that powers our daily lives works on the simple thermodynamic principle that a machine containing a difference in temperatures can create energy.

Now think big. In the tropics, the water at the surface of the ocean is very warm. The water at the bottom of the ocean is very cold. If we send a thousand-foot pipe down into the deep, we have a temperature difference, from the bottom of the pipe to the top, of 20 degrees Celsius. This temperature differential can drive a gigantic steam engine to produce a massive amount of electricity.

Ocean Thermal Energy Conversion, or OTEC, is a clean and renewable energy source. It’s environmentally sustainable, and it’s capable of providing massive levels of energy that can not only power an ocean city, but create enough extra power to fuel the land-based nations of the world.

“Pipe” dream? In 1979, Lockheed Martin constructed the first floating OTEC off the Hawaiian coast, which produced clean, green electricity. It worked! Soon after, the oil crisis ended, oil became inexpensive, and no more OTEC plants were built.

OTEC isn’t a futuristic technology. It’s an old technology that was shelved. The Office of Energy Efficiency and Renewable Energy (EERE), which leads the U.S. Department of Energy’s task force, reports, “Some energy experts believe that if Ocean Thermal Energy Conversion can become cost-competitive with conventional power technologies, it could be used to produce billions of watts of electrical power.”

Ted Johnson, a former Director of Renewable Energy at Lockheed Martin declared, “Water will be the next oil.” Ted Johnson’s new company, Ocean Thermal Energy Corporation, of which he became Vice President in 2011, has projects planned in several tropical island nations.

Imagine if Saudi Arabia was the size of an ocean, but to access the energy, we don’t need to drill into bedrock, only dip a pipe into water.

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If you go fishing on the high seas, you may be disappointed. Most of the world’s ocean is a lifeless desert where the nutrients that sustain life sink below where sunlight can reach to power photosynthesis. Organic matter sinks. For billions of years nature has been depositing all the ingredients necessary to sustain life on the ocean floor, which holds a virtually inexhaustible amount of fertilizer. In fact, the rich concentration of nutrients is suspended in seawater only 500 meters below the surface.

Nearly half of all wild seafood is harvested from less than one tenth of one percent of the ocean surface. These are the rare places blessed with natural upwellings from the deep ocean floor. Once sunlight and algae get a hold of that rich fluid, marine ecosystems flourish, each like an oasis of life in a vast desert.

Patrick Takahashi, a Hawaiian biochemical engineer, asks, “Why are we relying on natural upwellings covering one tenth of one percent of the ocean?” One hundred percent of the ocean floor is covered in the elixir of life. If OTEC plants allow us to double the amount of upwellings to, say, two-tenths of one percent, we double the amount of wild sea life we can create and harvest. A sizable platform will be needed to stabilize OTEC pipes. If we build a city on it, we have a self-sustaining ocean city and aquaculture farm. By accessing the unused nutrient wealth of the deep oceans, these floating metropolises would increase the number of ocean ecosystems without foreseeable limit.

OTEC plantships could also end wars for water. If you think the potential bounty of clean energy and renewable seafood is too good to be true, consider that OTEC plants create fresh water as a byproduct. Producing energy by evaporating sea water and condensing the resulting vapor means you are left with clean drinkable water.

Now compare agriculture to aquaculture. Agriculture supported by oil requires fresh water, produces C02, and drains excess nutrients into the sea, creating “dead zones” that harm marine life. Aquaculture supported by OTEC plantships will be supported by sunlight, produce fresh water, and absorb nutrients from the sea, creating ecosystems of bustling life.

Will immigrants move to floating OTEC cities that host aquaculture farms?

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According to Lockheed Martin, “each commercial OTEC plant would create 3,500 to 4,000 direct jobs. With the potential for thousands of OTEC plants, the economic impact would be enormous.”

Consider the potential for the blue economy. In 2009, 700 million poor and oppressed people told a Gallup poll they want to leave their countries forever and find freedom and prosperity for their children. That’s more than twice the population of the United States. Existing countries refuse to absorb them. Seasteads will require them to survive economically. To coax people to floating cities, better opportunities will have to be offered. Imagine millions of blue jobs causing a mass immigration comparable to the gold rush.

Infected with this vision, The Seasteading Institute has researched the potential for permanent floating ciies on the sea since it was founded in 2008 by Peter Thiel, co-founder of PayPal, and Patri Friedman, grandson of economist Milton Friedman and a third generation political theorist.

After five years of research, we commissioned the Dutch aquatic engineering firm DeltaSync to produce and design a feasibility study for a small floating city. In 2014, the Seasteading Institute was proud to release of our long-awaited Floating City Project report. Our key findings are:
1. A market for a residential floating city exists,
2. A practical design can be built to match the market’s price point,
3. The Seasteading Institute can secure a deal with a host nation willing to grant a floating city substantial political independence.

We conclude that the first floating city with significant political autonomy could be established by 2020.

In DeltaSync’s vision, the city will be composed of solar-powered platforms shaped like squares or pentagons with 50-meter sides. These platforms can be connected and arranged in numerous branch-like structures. The design features apartments, terraced housing, office space, and hotels. Eleven connected platforms could host about 250 full-time residents with an additional 50 hotel beds. This would cost $393 per square foot of gross space, but since 20% of each platform is reserved for green space, the report estimates that private space will cost $504 per square foot ($5425/sq. meter.)

Thousands of potential residents from at least 67 countries and many income levels have filled out our survey letting us know what they want from a floating city with political autonomy. The market demand for the first floating city is vigorous and growing. If such a small floating seastead prospers and attracts residents, DeltaSync believes the city could expand and move out into deeper water. Their long-term plan includes the construction of floating breakwaters made from modular units. This would allow the floating city to expand and enlarge to protect the city from waves. Once our floating city moves into international waters, it would be a true seastead, by which we mean a floating nation.

Now that we have laid the engineering, legal, and business groundwork for our floating city, we need artists to make it beautiful.

Rutger de Graaf, co-founder of DeltaSync, estimates that with 13% of the human population living on water, humanity will achieve harmony with nature, with any size population. According to DeltaSync’s figures, this would be achieved if we cultivate less than one percent of the ocean.

Floating cities are the next frontier. To get involved, or for more information, visit

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Seasteading: How Floating Nations Will Restore the Environment, Enrich the Poor, Cure the Sick, and Liberate Humanity from Politicians
by Joe Quirk with Patri Friedman

Hardcover — March 21, 2017. Available wherever books are sold.
Learn more about the Seasteading Institute at

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World Ocean Observatory

Written by

Dedicated to sharing information about ocean issues: climate to trade, culture to governance. The sea connects all things. Online at

World Ocean Forum

Fresh ideas, new solutions, serious, provocative, and imaginative conversations about the future of the ocean. An active forum of unexpected ideas, opinion, ideas, proposals for change in ocean policy and action worldwide.

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