[Sci-fi] Plausible scenarios for the evacuation of Earth at TL10-11

[tanksoldier]

The problem with your scenarios is that, absent cheap FTL drives and a convenient habitable planet, your scenarios are insufficiently dire for evacuation to make sense.

Exactly. Even if everything dies you still have gravity and air on Earth itself, you have the building materials on Earth... you have the people already on Earth.

Why build habitats in space when you can build habitats more cheaply and easily on Earth itself?

You need a disaster so big that it makes lifting all that stuff out of a gravity well and building in a vacuum with no gravity BETTER than building a similar habitat on Earth.

[Michael Thayne]

Without a lot of warning, the prospects for getting very many people at all off-earth are pretty grim. The most economical near-future methods of getting stuff into orbit require expensive infrastructure that would be almost impossible to scale up quickly: space elevators and laser lift systems. In a setting with roughly the THS level of development, I'd guess you're looking at being able to move somewhere on the order of ten million people per year—even with many years of warning, you're only evacuating a fraction of Earth's population.

But that's nothing compared to the problem of housing all those people. In a setting with THS-like rapid terraforming of Mars, maybe you could set all the minifacs to crank out very basic survival gear (CO2 filter masks and such), but otherwise the actual number of people you save is going to be much less than the number you could theoretically get into orbit in a year. (This makes sense if in your setting the orbital population is dominated by tourists and people who work in orbit for stints of weeks or months rather than years.)

[johndallman]

Originally Posted by Seneschal

A facet of EP that we did want to keep is the evacuation of Earth. This gives us several things we're looking for: a crisis that has affected all of civilization (but not made it unrecognizable) in the not-too-distant past, a new environment that humanity has to quickly adapt to, a shake-up of Earth-based geopolitics so that we may tweak existing cultures, social structures and economic systems, and an exploratory vibe, with various factions looking to resettle a derelict Earth.

Relevant SF: John Varley's Eight Worlds setting has many of the elements you're looking at, and is also a lot of fun.

[jeff_wilson]

A more efficient use of resources might be to construct aerostatic greenhouse domes, sometimes known as "Cloud Nines", that take advantage of the square-cube law to achieve buoyance with few cubic miles of air kept at shirtsleeve temperature. This keeps you well above most apocalyptic goings on, don't require rockets or spaceflight at all, and lets you replenish air and water at your leisure. Brave gondoliers descended from generations of champion Kramer Krane players can man the scoops to retrieve heavier elements.....