In a slightly future Earth I want to explore undersea colonization, but I need strong plausible incentives to emerge and convince people to do it. I could entertain societal, economic, geopolitical, technological, geological or other factors or combinations of these. I do not want just one eccentric billionaire or dictator with a crazy idea; but a sane reason that would encourage many independent groups to begin building undersea colonies.


closed as too broad by L.Dutch, Mołot, Frostfyre, sphennings, Azuaron Jul 26 '17 at 17:42

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    $\begingroup$ Welcome to Worldbuilding. Your questions make sense, but having multiple questions in one make it too broad. Please narrow it down to a specific problem. You are welcome to split it in multiple single questions. $\endgroup$ – L.Dutch Jul 26 '17 at 3:48
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    $\begingroup$ Several countries could be swallowed by the sea some time in the future, take the Marshall Islands for example. People also claim the Dutch are threatened, but I do not know if that could actually happen. So with enough global warming, we migth get even pretty advanced civilizations underwater pretty soon. This has of course happened in the past, take for example en.wikipedia.org/wiki/Doggerland or more recently en.wikipedia.org/wiki/Rungholt . I think the sea coming to us is your best and most realistic bet $\endgroup$ – Raditz_35 Jul 26 '17 at 6:02
  • $\begingroup$ Undersea evil lair. It's the hottest thing these days $\endgroup$ – Nahshon paz Jul 26 '17 at 10:25
  • $\begingroup$ Question narrowed. $\endgroup$ – Jean Luc Picard Jul 26 '17 at 15:33
  • $\begingroup$ That's not actually narrower... there's literally dozens of equally valid answers to this question. $\endgroup$ – Azuaron Jul 27 '17 at 14:39

As Alexander pointed out, the technological challenges are substantial. So there would have to be an even more powerful factor to push for undersea development.

  • Interested parties might create legal precedents that a seafloor settlement outside the EEZ of any existing nation does constitute a new, sovereign nation. That means building the settlement, not provoking any major power, and getting expensive lawyers.
  • Global warming causes the flooding of some island nation. To preserve their sovereignty and EEZ, they build a seafloor settlement. The ground happens to be more stable a couple of kilometres off the shore, and not directly in the surf.
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    $\begingroup$ Well done! I starred at this question a lot tonight and couldn't come up with even a single motivator for moving undersea. I thought about global warming and desertification destroying all above-sea farms, but even then I saw that green houses, shade houses and above-sea indoor farming would be easier than moving beneath the waves. I considered overpopulation, refugees and plague. I even considered extra-terrestrials. Nothing justified the cost. But both of your ideas do justify the cost. Independence and National Sovereignty! Excellent Answer! $\endgroup$ – Henry Taylor Jul 26 '17 at 5:54

For all I know the sea, i.e. very large amounts of water, provides an excellent radiation shield.

So, a credible driver for underwater colonization might be increased radiation levels, for example due to a missing ozone layer.

It would also help with credibility of the whole setup. Building a habitat for humans under the sea is technologically challenging, to say the least. At 100 m below the surface you have approx. 11 bar of pressure, some 11 times more than above the water. This constitutes not only massive load on any structure you build, most of all on the outer shell, it also provides extreme hazards in case of a breach of the outer hull.
None of that is impossible, but it's difficult, which equates to expensive.
It also means it cannot be done in a hurry, but you would need a few decades to build structures large enough to count even as a city, not to mention widespread colonization, as you ask for. Obviously, fear of an ugly death is a strong driver for such development, especially when it is paired with enough time to not only react but also to handle the notorious deniers.

So, the setup I would suggest would be that for some technobabble reason, the ozone layer is depleting. That is clearly noticeable, not reversible, and will continue to eventually become lethal for most life in the scale of 50 years or such.

As a radiation shield, you don't really need 100 m of sea water. You might also want to be able to make use of the harmless radiation, i.e. light, because it is mightily convenient. So I suggest your colonization starts in fairly shallow waters, on the continental shelves. That also facilitates construction, moving people and things back and forth, and whatnot.

After the first habitats are built, the technology will advance, as is always the case: do something often enough and you will get better at it.
Gradually, you can move more people into those habitats, providing at first part-time shelter, and then more and more as your facilities grow, while in the meantime your ozone layer becomes ever thinner, speeding the need to move under the sea while at the same time being able to provide room for ever more people.

So, to sum it up: The main driver could be ozone depletion and the resulting increase in radiation (UV mostly).

What would it look like: Mostly tubes and bubbles, to survive the pressure. On the inside: Anything you darn well please. And a realistic timeline might be half a century.

  • $\begingroup$ For radiation shielding, I don't know that underground cities won't be a more economic and technologically feasible en.wikipedia.org/wiki/Derinkuyu_underground_city $\endgroup$ – Nahshon paz Jul 26 '17 at 10:28
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    $\begingroup$ @Nahshonpaz i don't know about feasible. After all, moving a cubic kilometer of sea out of the way is generally considered much easier than doing the same with a cubic kilometer of rock. $\endgroup$ – Burki Jul 26 '17 at 10:55
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    $\begingroup$ At that depth, you encounter the problem of natural light and of course the heat. Also, it is needed for UV, as you can see in this underwater protection against UVa and UVb to go deep but other radioactives waves are actually not going that deep. You can read a bit about it in : Is the bottom of the ocean a good place to make a long-term base?. $\endgroup$ – AxelH Jul 26 '17 at 11:20

Undersea development is possible. Undersea colonization, with present technological level - no.

Building human habitat on the ocean floor is possible, but very technologically challenging. Even in shallow (<100m) waters, it is much more convenient to have above the see level platform and perform all bottom activities from there. A large scale mining of solid ores may require an actual base on the floor. Or it may not - it will all be decided by economics.

Colonization is different from exploration and mining. Colonization assumes that a colony could be self-sustainable, and we are not at this level quite yet. Colony requires energy, air, fresh water, food and other basic necessities. We can potentially have a nuclear reactor and derive all other things from its energy, but this setup would be expensive and potentially unsafe.


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