Three-quarters of the world’s megacities sprawl seaside. More than 40 percent of Americans live in oceanside counties. The National Oceanic and Atmospheric Administration projects that number will increase, even while the seas rise an estimated 20 feet over the next 80 years. Efforts to erect sea walls and implement massive pumping systems are underway in some locales, but even with those measures in place, tens of millions of people will be displaced.

Where will they all go? Most will go inland, of course, and maybe a few will join Elon Musk on Mars. But increasingly, technologists are envisioning off-land human societies—on the water, underwater, and in the air—and they’re developing the technologies that will allow it to happen.

None of this is to downplay the havoc being caused by climate change (or to suggest we should be less diligent about mitigating it), but as legendary sci-fi author Kim Stanley Robinson, whose recent novel New York, 2140 depicts a permanently flooded but still-vibrant Manhattan, says, “It’s important to stay positive about the future, no matter how messed up things are now.”

In that spirit, here’s a look at the new communities we can — and may have to — create.


Seasteading

In January 2017, a startup called Blue Frontiers made an agreement with French Polynesia, a nation that may lose a third of its islands to rising seas by the end of the century. The deal called for the company to build an artificial island (aka a seastead) hosting 300 homes, setting aside 25 percent of the spaces for Polynesians and creating what Blue Frontiers calls “the world’s first environmentally restorative community.”

That’s more than just a nod at sustainability — part of the seastead design process considers the local ecosystem and works toward minimizing environmental impacts, with rainwater harvesting, seabed monitoring, built-in composting, and, of course, renewable energy to power it all.

“Seasteads could be the technology for startup societies. It’s a Silicon Valley sensibility brought to the problem of governance that doesn’t get any better.”

What will this community look like? Picture a connected set of floating platforms, each of which supports a house or group of houses with balconies galore, connected by bridges and walkways and topped with green roofs.

Seasteading as a concept is still in its early stages, and working with existing countries are part of what Joe Quirk, president of the Seasteading Institute, a nonprofit think tank whose research inspired the Blue Frontiers project, calls “strategic incrementalism towards autonomy.” In time, he hopes the developments will become independent nation-states, with systems of governance left up to the people who found them. “Seasteads could be the technology for startup societies,” Quirk says. “It’s a Silicon Valley sensibility brought to the problem of governance that doesn’t get any better.” (That’s certainly how they’re hoping to fund the pilot project. The public presale of Varyon, a cryptocurrency to fund Blue Frontiers, ended on July 14.)

Right now, the technology exists for building a floating city in shallow waters, but what about a new mid-ocean community completely cut off from both an existing landmass and a sovereign government? “The fundamental challenge with [seasteading on] the high seas is waves, and the cost of stability in waves,” Quirk says. “The technology is available, but it’s expensive.”

Floating Pavilion, Rotterdam, Netherlands. Photo: Xavier TESTELIN/Getty

At present, that technology takes the form of the Floating Pavilion in Rotterdam, built by Dutch engineers to show how floating architecture works, as well as oil platforms and the Office of Naval Research’s Floating Instrument Platform (FLIP). The interiors of the FLIP rotate, and the vessel literally flips from horizontal to vertical to keep everything remarkably stable, even in 40-foot waves. This idea could be updated to allow for mid-ocean seasteading.

To be independent, any future ocean-based society will need to harness resources in order to maintain the technology keeping it afloat. That’s where Blue Revolution Hawaii comes into play. Both a book and a project by Patrick Takahashi, a biochemical engineer and director emeritus at the Hawaii Natural Energy Institute, Blue Revolution works “hand-in-hand” with seasteading, but its focus is less on governance and more on creating systems powered by ocean thermal energy conversion (OTEC).

This energy concept has been around since the Carter administration and utilizes the four-degree Centigrade difference between the ocean’s surface and deep-ocean temps. Takahashi says OTEC could easily power a self-sustaining city, complete with next-gen fisheries and on-site water desalination (a notoriously energy-intensive process). In Takahashi’s vision, there would be plenty of energy left over to create exportable, sustainable fuels, so the community would also have an income source. For instance, OTEC could be used to power a kelp plantation “to produce methane or a biomethanol product, or hydrogen from hydrolysis of water,” according to Takahashi.

First, though, some billionaires are needed. The technology is there, but the Pacific Ocean International Station, the first proposed step toward an OTEC-based energy system, will cost in the neighborhood of $1.5 billion — which the group is actively seeking.


Deep-Water Living

A lot has been made of so-called underwater hotels, but most are really just a lower-level room a few feet below the surface — more like a beneath-the-waves basement than the basis of an underwater society. Jules’ Undersea Lodge, however, is different. To get to it, you have to scuba dive 21 feet deep into a Florida lagoon.

Based in a decommissioned research lab called La Chalupa, the lodge was designed by undersea-living pioneer Ian Koblick, who is also the president of the nonprofit Marine Resources Development Foundation and author of Living and Working in the Sea. Koblick has lived underwater several times for up to three months and was one of the first people to live on the edge of the continental shelf, which he did for several weeks off St. John in the U.S. Virgin Islands in 1969. He calls it a “huge adventure,” and says he and the scientists who worked there went into it without knowing “if it was going to pan out or not — and we weren’t sure of whether you’d have long-term physical problems” from living underwater. Luckily, they didn’t.

When it comes to long-term subaquatic lifestyles, Koblick is the realist and Jacques Rougerie is the dreamer. Rougerie, who has also lived underwater for long stretches, once spending 71 days in La Chalupa in 1992, is a French architect who cites Jules Verne’s Nautilus and Jacques Cousteau’s Calypso as inspirations for his beautiful organic structures of future underwater living, from insect-like underwater rooms that together form a village, to a manta ray–like ship that can explore the deepest ocean abysses, to a renewably powered underwater lab that can house eight scientists called SeaSpace. He’s thought about necessities, too, like a sea farm that would allow deep-sea denizens — he calls them “Meriens” — to grow produce underwater, supplementing their diets of more readily available kelp and fish.

Some of Rougerie’s other creations are hybrids, with a portion of the design sticking up out of the water and the rest below, like the SeaOrbiter International Oceanic Station. Rougerie calls it a “slow-pace drifting vessel.” This design, inspired by seahorses, is neither tethered to the ocean floor nor powered to move; instead, it wanders with ocean currents. This low-power design would allow for solar or wave power to keep living systems going, since locomotion would be incidental.

For now, Rougerie’s ideas are still just that. Many would depend on advanced materials that don’t yet exist to deal with the realities of undersea living — a problem Koblick is all too aware of. “You see in these architectural renderings [of undersea structures], they always show these huge glass domes. They don’t realize someone has to be out there cleaning the dome every day or you won’t be able to see out of it in a week,” he says. “You’re liable to get mussels and algae and everything that grows on coral or rock growing on the glass.”

As much as Koblick loved his time underwater, he also appreciates the importance of natural light. He says that one of the “most memorable moments of my life” was when, after three weeks of living on the bottom of the sea, under its hazy light and cold temperatures, “we came out of decompression and saw the gorgeous palm trees waving, the blue sky, white clouds, and big sun.” There’s something to be said for living on the land after all.


Up in the Air

In his book New York 2140, author Kim Stanley Robinson writes about “sky-living in sky villages,” with small, self-sustaining farming communities floating through the air attached to balloons. To Robinson, the upside of this arrangement is clear: “To be on a stable floating village platform at about 10,000 feet would be really a great view all the time,” he says.

The downside: increasingly powerful storms — which are expected due to climate-change impacts.

That’s why the best bet for sky-living might be a more itinerant existence. Like Rougerie’s SeaOrbiter, a drifting approach could be a way to deal with atmospheric changes and winds without expending energy to fight it. “It is not easy [for a balloon] to stay in one place,” says Lodovica Illari, a senior lecturer in meteorology at MIT’s Department of Earth, Atmospheric, and Planetary Sciences (EAPS). “The atmosphere has very few stagnant points.” This is why most designs for airborne habitats involve balloons, which allow whatever’s attached to (or inside) them to go with the flow.

“With food and energy provided, [balloon-borne sky villages] would be a kind of wandering life with lots of possibilities for visiting places below; a kind of combination of travel and being at home in a small village.”

With a little help from an interface called the Float Predictor, designed by Illari and her colleagues, a balloon traveler can input where they want to go and the program will forecast which is the best day and time to catch the appropriate wind. In this way, it might be possible to slow-travel the planet, sailing along on the fingers of a jet stream.

Float Predictor was developed as part of the Aerocene project, with Argentinian artist/philosopher Tomás Saraceno. He wants to leave behind the violence of the Anthropocene — the geological era defined by human beings’ defilement of the planet — and usher in what he calls the “Aerocene…an era of ecological awareness, in which we learn to float together, live together in the air, and come to an ethical commitment with the atmosphere and the planet earth,” as Saraceno puts it in a TED Talk.

Whatever you think of Saraceno’s utopian vision, his thinking has some practical antecedents: When in residence with the French space agency CNES, he became acquainted with montgolfière infrarouge (MIR) technology: balloons powered by solar radiation from the sun and infrared radiation from the earth, which have been used since the 1970s by scientists taking air samples in the stratosphere. With no motors and no electronics needed to keep them operating, these simple balloons have proven longevity — one stayed aloft for 72 days. And they can scale, says Bill McKenna, a researcher at MIT’s EAPS who worked on the Aerocene project. The larger these balloons are, the more they can lift, and “with the technology that exists, they can lift quite a bit — as long as they stay clear of tall clouds below,” McKenna says.

Robinson suggests that solar energy, easily accessible in the sky, could provide such a floating village with plenty of power, enabling sky villagers to “do agriculture in some compact, intensive way,” he says. “With food and energy provided, it would be a kind of wandering life with lots of possibilities for visiting places below; a kind of combination of travel and being at home in a small village.”

Saraceno stresses that his ideas will inevitably run up against conventional notions of boundaries and borders, both horizontal and vertical. The troposphere (the atmospheric level we live in that’s below the stratosphere) is heavily regulated — both for strategic political and military reasons and the safety of plane passengers. However, McKenna says, the “stratosphere is more open to experimentation.”

Once you get into the stratosphere, of course, you’re above the clouds — and most weather. But then you’re too high for humans to live without being enclosed in a pressurized space. So the sweet spot for humans who might live in the skies would likely be heights of 7,000 to 10,000 feet, where most people are comfortable after some adjustment. There will still be weather to contend with, and McKenna points out that there are all types of no-fly areas out there. But perhaps, in time, navigating around or over them might be just another part of reexamining how we live.