By early next century, the rising sea levels may drown the beach coasts of San Diego and erode much of the city's seaward suburbs. This would make living and working there so troublesome and risky that many families and businesses might well venture to move to a more constant environment just offshore under the sea.
In this scenario of the future, a suburb of San Diego is resurrected in 2121 within the sea. Using the technology fashioned and perfected from one hundred years of oceanic exploration, as well as from the experience of San Diego’s US Navy submarine fleet, these submarine homes-- suitable for about ten people each -- are tethered, like giant California kelp, onto the rocky sea floor using robust holdfasts.
The idea of such a sea-bound community is not just to hedge bets so that San Diego may survive drastic sea-level rise but also to promote eco-friendly lifestyles in the sea using traditional and novel techniques of mari-culture. It will still be an expensive enterprise, however, but there’s a commercial impetus from the growth of the seaweed bio-fuel industry which by the early 22nd Century may serve to fully replace fossil fuels.