There are major environmental differences between living on land and living at sea. To start with, we can talk about Natural Disasters.
On July 27th, 2022 the Philippines experience a magnitude 7.2 earthquake. Here in Manila, the towers were swaying back and forth like a ship in the waves for almost a full minute. Every year, earthquakes strike dozens of countries across the globe, and unlike seasteads, much of the infrastructure they impact is not designed to endure sustained swinging motions. The 2010 earthquake that struck Haiti for example was magnitude 7.0 and killed over 150,000 people. The difference in damage between these two countries lies in the difference in infrastructure. With the Philippines being located along the Ring of Fire, earthquakes are much more common and they are taken into account in every aspect of the building codes.
At sea, seasteads will be subject to wave motion which is somewhat similar to the motion of the Earth during an earthquake, but seasteads are always specially designed to handle this motion. Moreover, the force of earthquakes cannot pass through water. So unlike buildings on the coast, which may rock and sway in the waves, a floating city located just a few miles away during an earthquake will be completely stationary and unaffected by powerful forces. This is one advantage of living at sea.
Another natural disaster that you are insulated from on the ocean is tsunamis. As counterintuitive as it might seem, tsunamis are only dangerous near the shore. In the deep ocean, a tsunami is notable for having an extremely long wavelength, so long in fact, that most ships will pass over the slight increase in water level without even noticing that a tsunami had just passed. It takes special instruments to measure water pressure at depth to know if a tsunami is passing through, but as the wave nears the shore, it grows taller and taller, and gets slower and slower, until eventually, it crashes into the land and washes over coastal structures, destroying them in the process. Over 260,000 people died in the Indian Ocean Tsunami in 2004, brought on by an earthquake in Indonesia.
Other dangers especially prevalent in the Philippines are floods and landslides, again two dangers that can only happen on land, as in the ocean there are no mountains for landslides to take place on, and any extra rain simply slips off the roof and into the ocean. Drought is also a non-existent threat since desalination can always be increased if there is a lack of water, but since drought is usually only dangerous for crops, this threat is doubly unimportant on a seastead, since most crops we grow will be aquaculture and not agriculture.
In fact, almost all known natural disasters from tornadoes to forest fires simply can’t occur in the ocean. The only exceptions to this are hurricanes, but we can position seasteads in areas that are never hit by hurricanes.
So besides natural disasters, what are some other ways in which life on land is different from life at sea? Well one stark difference, is how wildlife is incorporated. On land, pests such as rats, bats, and other creatures are exterminated on sight. Even deer and raccoons are undesirable in cities and can be a nuisance. On land, animals flee before civilization, but in the ocean, they can live in harmony with it. A floating city will have urban infrastructure on top, but be productive farmland beneath the waves. As the city grows, the amount of algae, seaweed, and kelp grows with it, as well as the fish population that will thrive in such an environment. As the fish population grows, you can expect to see more squid, dolphins, whales, and other marine life. Some more exotic species can even be grown by individual households as a side job. Some species of urchin and sea cucumber can sell for upwards of $50 a pound, you can imagine a cottage industry of exotic seafood popping up in every city offering a different species of exotic food. Compare this with land, where you can’t grow crops in the city, and even in rural areas where you can you are typically limited to tomatoes, strawberries, or other small well-known food products that can be grown on small plots.
In a floating city, you have more than just the freedom to grow your own food, generate your own electricity, and start your own business, you can also choose where you want to live without selling your house. Since every house can be detached from each other and re-arranged to be located somewhere else in the city, you can move at the drop of a hat for a much lower cost. This also has a huge impact on housing prices and makes us rethink our very concept of real estate. A good neighborhood turning bad will no longer affect housing prices for instance since the home can simply leave the neighborhood whenever it wants to.
Lastly, let’s not forget the passive health benefits of living at sea. The algae and seaweed in the ocean act as a passive carbon filter, drawing CO2 out of the air and refreshing it with oxygen all day. Some scientists have said that living near the ocean can be better for your health, and certainly, with a power grid based on solar and OTEC the total lack of pollution in the air will lead to healthier people overall.