[ASB] Sea level drops by 50 metres in the early 20th century

[SinghSong]

How do the ships in the docks and slipways at London, Southampton, Portsmouth, Dover, Cardiff, Bristol, Hull, Liverpool, Dublin, Queenstown, Middlesbrough, Glasgow etc get to it, however?

On wheels?

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Like I showed in the images above, the paleo-channels of the ice age rivers are still there, under the water. And they'd still combine and run again if sea levels fell once more. The Solent itself's the submerged, flooded channel of an ice-age river, after al- and most of the surrounding sea ports would still be situated along the banks of the river and its tributaries. With the former Solent River Valley being the main reason why the Isle of Wight came into existence at all in the first place. The sea level may be falling, but if there's still rainfall, those rivers'll still keep flowing all the way to the sea (though it's still anyone's guess how the rivers' respective flows might be altered by the ASB's POD), and permit riverine trade to endure.

It'd still be fairly sheltered, and have access to the Atlantic. Along with Cork & Dublin (where as you can see on that map you included, there'd now be convenient new natural bays to harbor ships in, at the new mouths of the Lee and Linney Rivers, looking out over the Celtic and Irish Seas, both of which are still open to the Atlantic). Sure, they'd have to move the docks in Cork and Dublin c.5 to 8 miles downriver respectively; but the historical port city of Bristol's docks were 8 miles inland as well, and Bristol still survived, and continued to thrive after they moved its docks downstream to the mouth of the Avon.

So the UK's capacity to traverse the seas certainly isn't an automatic write-off ITTL. But maintaining control over (the former island of, now peninsula of) Ireland's just gotten way, way more important for the British. And for further context, the new coastlines in the North Sea and British Isles, post ASB-event ITTL, would roughly correspond to the '8000 B.C.' coastline on the map below- from which one can see that there are a fair few other pre-existing paleolithic river channels which'll re-emerge, the mouths of which'd still be prime sites to relocate any newly-built docks to, from the former mouths of their respective tributaries:

All the rivers which feed into The Humber and The Wash estuaries'll all merge back into one as tributaries of the 'Greater Ouse River'; likewise, all of the rivers which feed into the Severn Estuary into the 'Greater Severn River', and all of the rivers which feed into the Eastern Irish Sea south of the Isle of Man are set to be tributaries of the restored 'Greater Mersey River'- all of which'd comfortably have a greater flow rate, and thus presumably carve out deeper channels, than the present-day River Severn.

 

[Arthur_Phuxache]

It, along with Cork Dublin (where as you can see on that map you included, there'd now be convenient new natural bays to harbor ships in, at the new mouths of the Lee and Linney Rivers, looking out over the Celtic and Irish Seas (significantly reduced, but still wide and deep enough, to carry seafaring traffic, and open to the Atlantic).

Sure, they'd have to move the docks in Cork and Dublin c.5 to 8 miles downriver respectively; but the historical port city of Bristol's docks were 8 miles inland as well, and Bristol still survived, and continued to thrive after they moved its docks downstream to the mouth of the Avon. So the UK's capacity to traverse the seas certainly isn't an automatic write-off ITTL. But maintaining control over (the former island of, now peninsula of) Ireland's just gotten way, way more important for the British...

Where does the money/labour/machinery come from to build these new dockyards, now that world trade has collapsed, fishing and agriculture are unviable, and people are starving?

It's a gradual extinction level event. Most of the world's population will die off before anything can be done, like most of these big ISOT/ASB events.

 

[SinghSong]

Where does the money/labour/machinery come from to build these new dockyards, now that world trade has collapsed, fishing and agriculture are unviable, and people are starving?

It's a gradual extinction level event. Most of the world's population will die off before anything can be done, like most of these big ISOT/ASB events.

Necessity tosses those sorts of considerations up in the air. The British Empire used military pioneers to carry out civil construction projects effectively free of charge, without any extra pay or bonuses to the soldiers/press-ganged workers, as part of their 'military and civic duties', on multiple occasions IOTL- that's where all the money/labour/machinery needed to build most of British India's railways, canals and ports came from (most of it going into the hands of the corrupt administrations, of course).

You seriously think that such a catastrophic extinction-level event wouldn't be getting every industrial nation on earth declaring states of emergency and martial law? That they wouldn't be putting their old 'navvies', and the Royal Pioneer Corps (or the regional equivalents thereof), to work harder than they'd ever worked before, to desperately try and save themselves (and everyone else) from literal extinction? And that if the economy collapses to the extent where they're no longer to provide the workers a living wage, they wouldn't simply employ conscription, and perhaps even revert to fully-fledged serfdom, in such a dire situation?

 

[fluttersky]

How do ship-owners/ship builders know where to anchor their ships, without knowing how much the sea level will drop? The tide will go out, and not come back.

The maximum rate of sea level drop would be around one inch per day. Enough that it can be adjusted to.

Where does the money/labour/machinery come from to build these new dockyards, now that world trade has collapsed, fishing and agriculture are unviable, and people are starving?

I don't really think that argument about fishing/agriculture being unviable and world trade collapsing is likely to be accurate.

My intent behind this ISOT scenario was very much one of "recognizable but different world"- do you think it would be better if it occurred at the start of the 19th century rather than the start of the 20th century, i.e. pre-industrialization and with world maritime trade being of relatively less importance?

 

[Arthur_Phuxache]

My intent behind this ISOT scenario was very much one of "recognizable but different world"- do you think it would be better if it occurred at the start of the 19th century rather than the start of the 20th century, i.e. pre-industrialization and with world maritime trade being of relatively less importance?

It's a bonkers idea whenever you set it, and it will cause as much misery and death as a new ice age.

The idea that existing population levels/communities/nations/empires will survive this inexplicable ecological disaster (where has seawater actually gone?) is implausible.

Why would they?

 

[SinghSong]

It's a bonkers idea whenever you set it, and it will cause as much misery and death as a new ice age.

The idea that existing population levels/communities/nations/empires will survive this inexplicable ecological disaster (where has seawater actually gone?) is implausible.

Why would they?

Existing population levels/communities/nations/empires? Probably not- though there are going to be plenty of exceptions (can't see this afflicting landlocked countries/regions too much, at least not relative to everyone else). And at the very least, some people/communities/nations/empires WILL survive this. Why wouldn't they?

That being said though, might also be worth factoring in how, using the dry adiabatic lapse rate of around 10 °C (18 °F) per kilometer of altitude, lowering the sea level by 50m (with the water effectively evaporating out of existence, rather than being locked into ice caps as happening during the polar maximums) will also automatically cause global average temperatures, at sea level, to rise by 0.5 °C in the same time-frame of just ten years (such that you'd basically see TTL's sea level temperatures, in 1910, being roughly on a par with sea-level temperatures today IOTL).

And how much drier would said world be, if the ocean shrunk by such an amount (with a fall of 50m representing roughly 2-3% of the water on earth being teleported away, BTW)- how would this affect stuff like precipitation and desertification? Although, having said that, the total volume of water that's been lost ITTL, to reduce the world's sea level by 50m, is roughly equivalent to the volume that's locked in the polar ice caps, and tundra permafrosts. Meaning that if this does lead to practically all of the world's ice caps melting due to accelerated global warming, the resulting sea level rise would just return the world's sea level to roughly what it was before (thus potentially being spun by the ASB itself as "pre-emptively saving human civliization, ensuring they won't be flooded into oblivion by anthropogenic climate change a couple of centuries down the line, as would otherwise have been inevitable! But with way less loss of life, since they've only got less than a fifth of the population and don't have nukes yet!").

Might be more fun if the ASB actually did something with all that water though, like teleporting it away via a deep-sea portal to Mars. In which instance, if and when earth-bound civilization managed to recover and develop to the extent where it became spacefaring, Mars would be a lot more habitable ITTL, and represent a suitable prize for TTL's 'winner of the ASB survival challenge'...