It sure an extinction level event, but let's investigate a little bit the capacities of making floating means, which they may need in this situation
I won't bother for looking ww2 productiin capacities, and will use fresh data from google for whatever I need, so scale down if you need it, anyway future looks grimm for them so it does not matter that much.
Production world wide, per year:
- concrete - 4.4 billion tons
- steel - 1.9 billion tons
- electricity - 27 million GWh
- natural gas - around 3000 billion cubic meters
There is no time to adjust production of energy, electricity etc - 1 year is too short, and best case scenario is to dump all there is in to making safe jakets.
Appropriate/considered technologies of that time:
concrete cargo ships - were build back then, lasts for quite long, sure has some cons but a legit war tech
zeppelins, and alike
usual iron ships, pontoons etc
cast basalt-gabbro-diabase ships pontoons - more like pontoons, more or less fictional application of this realy existing technoloy
Floating means design and required numbers:
Nothing complicated, proper ships take too long to build, so it more like smaller size pontoons, which then assemblied in some sort of island, floating platphorms - so more like square minecraft design, and more attencion is how much tonnage can be produced.
Assuming gradual decrease of production capacity, proportional to land mass dissapearance, which not so realistic, but if then numbers needs to be slashed in half. But real situation may be worse, or may be better(unlikely, but on the other hand war time efforts, then maybe) so that coefficient is not known, so let's assume best case - they do manage to produce those annual numbers, this or another way.
What is typical ratio of mass of a ship to cargo it can take - do not remember exact number but it around 1to6 to 1to8 ratios, will take lower number here, more robust crude construction, so 1 to 6.
materials used(mass) to payload it can carry - 1 to 6
To cast 1 tonne of stone it requires about 1MWh of electricity, steel is the same.
what do we have as result
Concrere pantoons - 4.4 * 6 = 26.4 billion ton
Steel pantoons - 1.9 * 6 = 9.6 billion tons
Cast stone pantoons - 27 * 6 = 162 billion tons
Zeppelins filled with NG - less than 1.5 billion tons displacement, and more like half or less of that number as payload
note
oil extraction is not counted and that about 6 times the electricity we generate, and considering that stone cast stuff may be the winner, it worth put max of oil energy as just a heat in to meltig and casting those stone pantoons. Not every stone is good for it, and it requires energy to extract as well, but usually it still cheaper than iron ore extractio.
ability to scrape cars and such for steel is not counted - and considering how much is produced yeach year, there should be a sizeable pile to recycle, but more or less this potencial is covered by stone castig.
what do we have at the end and what it gives to those guys.
Rounding up, they have about 200 billion tonn capacity, the for 10 billions it is about 20t per human, more than I was initially expecting
In therms of surface area, let's take 1m tick pantoons, it is too little, but to increase surface area, best case scenario - 20 million ha (or about 40 million acres)
So with 10% dietary need to be provided by plants grown ther(only necessities for vitamins and fiber), and 90% by fishing it may be sufficient for 400 million people
number may be more, or less. It like in assumption 2 people per ha, assuming yeilds one typically see 3-4t of food from ha won't be in place as problems of fertilisation, sea water moist and all kinds of problems. Google also isn't that much helpfull saying sustainable food growth requires 5 acrs per person, so as aquaponics setup is enough for 100 people per ha - so a big uncertanty here
aquaponics setups, and associated technologies should be a priority for reasons of high production yeilds, so as it is the way to keep microelements and other fertilising stuff in the system
If we take aquaponics system, with 100 people per ha, and it being just 10% of their food(initially), then we can get 20 billion people capacity. So surprisingly there are potencial scenarios when every one is taken, instead of 4% lottery ticket.
But that's an initial number not sure how sustainable is such a degree of fishing but if not, it can for sure prolong the struggle at least by few years. Where will be also natural decline of population (medical service is none, quality of food is different) so as other factors.
conclusion and perspectives
So there may be scenarios where most people are saved, at least for few more years, with expected significant decline of population, even if all are taken.
Technological competencies can be saved, as even for a less optimistic scenario population is high enough for that, but the main problem is that energy sources become inadecuate for implementing that theoretical knowledge, the problem can be solved, but it a long road.
Keeping stuff affloat probably a manageble activity and next 40-60 years it may be assumed they retain 70-80% of their fleet. Concrete ships did last for 60 years so, if they resist initial devastatin and struggles, they may have a chance to turn the table - they will have few decades at least.
So, in a reasonably optimistic scenario, humanity can retain its technological capacity, and not die out, even if probability of such scenario is low, but there is a road out.
P.S.
Can't answer in comments due se broke site for me, js or what so do it this way
- How do you continue to mine natural reources from the now submerged earth with WW2 technology? Solar is not an option. – @Trish
OP gave initial conditions, I filled the gaps in those conditions, and clearly stated them. I have such freedom of intrpreting the question because OP isn't dead set on any specific development, he just wants the end result - land mass is no more sticking above sea level.
And he gives 1 year to prepare, I guess it reasonable to assume some speed of sinking, and end of the year tip of everest makes T-100 I'll be back, but just under the water. At very least OP didn't state it sinks in 5minutes now, and his attempts to word the question clearly indicate it is a gradual process. So some portion of land is available until the last minute of the year.
I like that @Pelinore comment:
- "something went wrong and earth’s solid terrain has been liquified" 🙄 Umm [holds up hand] that might have been us [shuffles feet and looks a little embarrassed] some malfunctioning self replicating nanobots originally designed to build flat road surfaces accidentally fell into our prototype experimental temporal displacement device in the now non existent future of 2417 and proceeded to turn the entire planet into a smooth spheroid, sorry about that, just one of those things, a freak accident, shouldn't happen again 🤗 – @Pelinore
I had similar scenario in mind, flattening the planet, and wrong depth is set, and wrong planet - in that sense I didn't had the problem may or may it not happen - if it can be done it may happen. But I decided to skip that part, as it not so relevant for the q.
My goal was to investigate what is a best case scenario, is there in such scenarion any best case and how it looks like, what are some numbers about it, what kind of size it is - is it enough for anything or not. I'm not interested to develop a story for the OP, but I interested to know is there a potencial for a story at all or not in such conditions. It turns out, that to contray to my initial expectations - there is a potencial for such setting, and that all I wanted to know.
And specifics in which way and how access to resources dissapear it all up to one who writes the story, I do not, I just say what can be done with certain resources, which are left or right of a number some one may have in his story.
To flesh the stuff with more aspects it quite a work, but in some sense it is typical doomsday and boostrapping combination. That bootstrapping aspect is what attracted me, and which potencial (is there some or none) I was evaluating.
I would like to comment on your answer as well, just that "nor does Newtonian physics allow it" - there is a potencial energy of high spots which can be used to flatten things, and more so processes of errosion do happen continiously it just slow - so it already happening meaning physics already allowed it, at much lower speed, and if there is an catalyst of the process, in my and Pelinore case those are nanomagic - it has the energy it needs for the process and physics isn't there to object the case.