Hundreds of years in the future, the surface of the Earth has become unlivable.

Vacating our terrestrial settlements, our species migrates into the ocean and begins

a new chapter underwater.

Could humans build neighborhoods and cityscapes on the ocean floor?

Could our species colonize the ocean with bio-domes and giant air bubbles?

If the surface of our planet can no longer sustain us, will humans ever live underwater?

The surface area of Earth is approximately 197 million square miles; however, 71% of

our planet is covered in water.

Around 80% of that water has never been explored.

Logistically, studying the ocean is similar to studying a foreign planet.

We can’t breathe underwater, just like we can’t breathe in an extraterrestrial atmosphere,

so we rely on specialized equipment to investigate sub-aquatic habitats.

Investigating the ocean is a constant challenge; but for a moment, let’s think outside of

scientific research.

During the 21st century, the population of our species could rise to astronomical heights—an

estimated 11 billion by 2090.

As our population increases, our ecological footprint will follow.

The Earth’s climate will become increasingly dangerous.

The average global temperature will increase by several degrees.

Violent storms, scorching heat waves, and infectious diseases could ravage the world’s

ecosystems.

By the end of the 21st century, humans may need to escape from the Earth’s unlivable

conditions.

If anthropological damage wasn’t frightening enough, a natural disaster could also transform

life on the surface of Earth.

For instance, a series of towering, super-volcanic eruptions could fill the atmosphere with toxic

chemicals, forcing humanity to vacate the surface of Earth.

But where would we go?

To safely avoid fluctuations in the Earth’s climate and toxins in the atmosphere, humans

may retreat to underwater sanctuaries—entire colonies built below the ocean waves.

If the surface becomes uninhabitable, the colonization of the ocean could be a necessary

step for the preservation of our species; but there’s a greater question we’ve yet

to address.

Could humans actually live underwater?

Any ocean-based habitat must satisfy a short-list of basic human needs.

A functioning settlement must guarantee the safety, survival, and comfort of its inhabitants;

however, providing even the most essential human needs creates several unique challenges.

In terrestrial ecosystems, humans can breathe freely, but humans rely on technology, like

SCUBA equipment, to inhale and exhale underwater.

Like astronauts in space, we cannot survive in the ocean without a constant and reliable

source of air.

Before we build homes and cities on the ocean floor, we have to create a breathable environment,

like a giant bubble, cycling a steady stream of breathable air.

Pressure control is another necessity inside any ocean habitat.

At the surface, humans have adapted to atmospheric pressure; but, for every 10 meters underwater,

the pressure increases by one standard atmosphere or atm, a unit of measurement that describes

the pressure we experience at sea level.

Below 25 meters, inert gases like nitrogen can trigger a condition called inert gas narcosis,

which alters your central nervous system, leading to faulty judgment and hallucinations

similar to the effects of an anesthetic.

To avoid inert gas narcosis, many divers fill their tanks with Heliox, which combines 21%

oxygen with 79% helium.

Decompression sickness, also known as “the bends,” is yet another inevitable hurdle

If a diver returns too quickly to the surface, nitrogen bubbles called air embolisms can

form in their tissues and bloodstream.

These bubbles can block your major blood vessels, cause excruciating joint pain, and damage

your internal organs.

Thus, divers must swim to the surface very slowly—at a speed of 33 feet per minute

with regular stops—so these harmful gases can escape their bodies.

Can you imagine fighting the bends every time you navigate your underwater home?

Because of these incredible challenges, it’s unlikely human beings will settle in the deepest

parts of the ocean.

Some theorists have proposed radical concepts like skyscrapers standing on the deep seafloor,

but the pressure alone would endanger anyone who lived there.

An enclosed, surface-level colony would create a much safer habitat with lower risks of narcosis

and decompression sickness.

A surface colony also offers direct access to important terrestrial resources like air

and sunlight.

If we want to create a functioning underwater habitat, we may need to build that habitat

as close to the surface as we can.

But even a shallow colony will depend on a powerful life support system.

The system must circulate a stream of mixed gases, modulate internal temperatures, control

humidity, and recycle excess carbon dioxide inside of the colony.

A similar system supports the only undersea laboratory in the world, the Aquarius Reef

Base.

Aquarius is located 3.5 miles off the coast of Key Largo in the Florida Keys National

Marine Sanctuary.

This base provides researchers with a unique opportunity to live beneath the waves and

collect data first-hand from coral reefs.

Aquarius is stationed at a relatively shallow depth of 15 meters.

Researchers known as aquanauts can work inside the reef base indefinitely, but before returning

to the surface, they must undergo 17 hours of decompression.

The longest-standing aquanaut was Fabien Cousteau, grandson of famous oceanographer Jacques Cousteau.

In 2014, Cousteau lived and worked inside Aquarius for 31 consecutive days, during which

he collected the equivalent of two years of data.

Assuming we can surmount the physical challenges of undersea habitation—like breathable air,

high pressure, and dangerous illnesses—what would an ocean-based, human colony look like?

In 1998, futurist Philip Pauley designed an underwater colony called the Sub-Biosphere

2.

His adaptable, sub-aquatic settlement could house 50 to 100 occupants as well as small

populations of animals and plants.

This intricate structure was designed to imitate the diversity of our terrestrial environment.

Using isolated bio-domes, Pauley theorized miniature, sustainable ecosystems, like a

rainforest, a desert, and a coral reef.

Other futurists have pushed the envelope in different directions.

One devised a massive, underwater globe, constructed around a sprawling city center.

Another interesting concept was developed by a Japanese company called the Shimizu Corporation.

They proposed a deep-sea spiral that connects a resource-sustaining factory on the ocean

floor to a livable, 500-meter sphere floating just below the surface.

As it stands, humans do theoretically have the technology to build underwater habitats.

We could create bio-domes, ocean globes, and underwater factories; but total self-sufficiency

remains a challenge.

Humans rely too much on the surface of the Earth for life-sustaining resources, and that

isn’t going to change anytime soon.

In the not-too-distant future, however, humans may adopt a hybrid lifestyle.

We may seasonally inhabit untapped regions of the ocean to avoid dangerous climate conditions.

But first—this field of research needs a surplus of money and resources.

Right now, all eyes are staring into space, looking for a new home in the cosmos.

But the future of humanity could be waiting underwater.