Fictional science premise: How could the sea submerge most of the Earth's landmasses?

[Meurglys]

Stephen Baxter is generally considered a ‘hard’ science fiction writer and this is part of the blurb from his recent novel, Flood.

the world is drowning and there is nowhere left on earth to go. Next year. Sea levels begin to rise.

The change is far more rapid than any climate change predictions; metres a year. Within two years London, only 15 metres above the sea, is drowned. New York follows, the Pope gives his last address from the Vatican, Mecca disappears beneath the waves.

Where is all the water coming from? Scientists estimate that the earth was formed with seas 30 times in volume their current levels. Most of that water was burnt off by the sun but some was locked in the earth’s mantle. For the tip of Everest to disappear beneath the waters would require the seas to triple their volume.

That amount of water is still much less than 1% of the earth’s volume. And somehow it is being released. The world is drowning.

The biblical flood has returned. And the rate of increase is building all the time. Mankind is on the run, heading for high ground.

Nuclear submarines prowl through clouds of corpses rising from drowned cities, populations are decimated and finally the dreadful truth is known. Before 50 years have passed there will be nowhere left to run. FLOOD tells the story of mankind’s final years on earth.

I haven’t read it, so I don’t know the details of how the water is released but I assume Baxter has found a somewhat plausible mechanism for it to happen.

[Asuka]

@Meurglys

Stephen Baxter is generally considered a ‘hard’ science fiction writer and this is part of the blurb from his recent novel, Flood.
I haven’t read it, so I don’t know the details of how the water is released but I assume Baxter has found a somewhat plausible mechanism for it to happen.

I believe scientists recently discover there’s actually more water underneath the Earth’s crusts?

I believe fluid dynamics would dictate that even if the crust were pierced the waters underneath the crust would just stay as they are but I’m no expert.

[Ludovic]

I think I got one scenario. A terrorist organization, or science experiment gone wrong, builds auto-replicating space probes that divert the aforementioned icy comets to the planet. Perhaps the terrorists programmed them to mostly rain down in the Pacific (perhaps each one comes with a self-correcting rocket for adjustments) because they are landlocked and thus will not suffer the flood themselves.

[watchwolf49]

@Asuka

I believe scientists recently discover there’s actually more water underneath the Earth’s crusts?

I believe fluid dynamics would dictate that even if the crust were pierced the waters underneath the crust would just stay as they are but I’m no expert.

The Earth’s core is made of Ice XLIII, a remarkable crystal structure that appears to be exactly like iron … humans drill down and pierce the protective shielding … with the pressure release liquid water streams out covering all the land …

Make it a slow process so the horror builds as more and more people fight for less and less land …

[Grey]

Peppering the world with ice comets requires that they have some sort of ablation shield allowing the majority of the mass to reach at least the lower atmosphere. That means a lot of heat getting dumped into the air.
That said a “sauna Earth” nefarious plot would be almost more troubling than just a sea rise.

[MrDibble]

@eburacum45

Europa probably has 2-3 times the water of Earth.

Not quite.
And I wanted a waterworld for the pressure differential. I think Europa would reach equilibrium a lot sooner than a watery superEarth.

[Ludovic]

I have thought about the heat release of comets but I do not know how much that would be. Does anyone have any numbers for that? I was thinking of a story myself where there were comets diverted to replenish (rather than increase) Earth’s water, and the heat release would be part of the story, so ideally it should be plausible that the heat release would be large enough to be noticeable but small enough that humans could still live after taking appropriate measures.

[MrDibble]

@Meurglys

Stephen Baxter is generally considered a ‘hard’ science fiction writer and this is part of the blurb from his recent novel, Flood.
I haven’t read it, so I don’t know the details of how the water is released but I assume Baxter has found a somewhat plausible mechanism for it to happen.

The existence of the components of water in the mantle isn’t in doubt (it was confirmed finally in 2014, after Flood was published, when ringwoodite was found as diamond inclusion) but it’s not in the form of H[sub]2[/sub}O and I don’t think Baxter provides an actual mechanism for getting the water out, he just postulates “mantle oceans” or some such thing, whereas the actual mechanism of water cycling to the deep mantle involves outgassing from mantle melts, which isn’t going to leave a lot of spectators when the outgassed water vapour eventually condenses in a million-year rainstorm. So, yeah, loosely based in science, but about as “hard” as my wormhole idea.

[MrDibble]

@Ludovic

I have thought about the heat release of comets but I do not know how much that would be

Lots.
Instruments on Galileo detected a fireball that reached a peak temperature of about 24,000 K, compared to the typical Jovian cloudtop temperature of about 130 K, before expanding and cooling rapidly to about 1500 K after 40 s. The plume from the fireball quickly reached a height of over 3,000 km

That was just from the first fragment, A, of one comet. Note that 3000km is half the radius of the Earth. Then read about fragment G at that link…

[watchwolf49]

We could bring the comets in slower, so that the heating only melts the ice, letting the liquid water rain down nice and slow … gobbling up land while more and more people fight for less and less land …

[Leo_Bloom]

Heard this three prime ministers ago:

So, it’s proven that the Earth will be flooded in two weeks. Pope gets on mass media: Now is the time for all of us to enter Christ’s embrace. Grand Mufti in Mecca (or whatever, it’s a joke fer Chrissake), same, says: it is finally upon us that Allah has summoned his servants. Netanyahu in Jerusalem: we have two weeks to learn how to live underwater.
ETA: Carry on.

[LSLGuy]

Here’s some good info about the effects. Not necessarily about a good cause, but still useful to an author.

https://what-if.xkcd.com/53/
https://what-if.xkcd.com/54/

I like that Flood scenario in post #21. Shame it’s already taken and just recently to boot.

[Francis_Vaughan]

We just need to start trucking the higher bits of the continents out and dumping them into the oceans. Eventually[sup]*[/sup] we will achieve any chosen mix of land and sea. It will require long term maintenance as the isostacy of the crust will start to push the now heavier oceanic crust down and the lighter continental crust will start to rise. But we can keep trucking rocks across and eventually[sup]**[/sup] we should achieve a stable configuration.

*for large values of “eventually”.
** for extremely large values of “eventually”.

[LSLGuy]

That reminds me …

When I was about 7 my grandfather and I were walking in a nature park. After I did something he said “Someday the world will be completely flat. And all because little boys will keep throwing rocks off of hills and into valleys.”

Wise man he was.

[md2000]

Recall that the recent meteor in Siberia, thoughtfully captured on dashcams and security video across a huge swath of Russia - blew out windows and caused damage dozens of miles away from the path of the object. that one was calculated to be about 70 feet in diameter. IIRC, the meteor that gave us mammals superiority over dinosaurs was estimated to be 10km diameter.

The Chicxulub impactor had an estimated diameter of 10 km (6.2 mi) or larger, and delivered an estimated energy of 420 zettajoules (over a billion times the energy of the atomic bombings of Hiroshima and Nagasaki).[19] By contrast, the most powerful man-made explosive device ever detonated, the Tsar Bomba, had an energy of only 210 petajoules (the yield of 50 megatons of TNT),[20] making the Chicxulub impact roughly 2 million times more powerful. Even the most energetic known volcanic eruption, which released an estimated energy of 1 zettajoule (the equivalent of approximately 240 gigatons of TNT) and created the La Garita Caldera,[21] delivered only 0.1% of the energy of the Chicxulub impact.

I’ll leave the math to others, but 2/3PI*R^3 where R=5km is probably not enough volume for a huge rise in sea level. Don’t forget, there are plenty of mile-high cities…

Hitting earth with enough ice to impact the sea level would be very interesting.

[dracoi]

I would suggest some kind of volcanic mechanism, but I think the most extreme one we have an example of is the Siberian Traps region. Checking the numbers from Wikipedia, I see that as much as 4 million cubic kilometers of material was laid down. If you did that underwater, it would be a substantial displacement… but since Antarctica alone has twice as much water locked up in ice, it’s still not as dramatic a rise as global warming alone. Even with lots of sci-fi handwaving, it’s hard to justify all this magma doing more than doubling the sea rise from melting ice alone. Plus, the original event took place over millions of years. If you sped it up, the toxic gas from that much volcanic activity would kill humans almost as fast as being underwater.

[dracoi]

@watchwolf49

We could bring the comets in slower, so that the heating only melts the ice, letting the liquid water rain down nice and slow … gobbling up land while more and more people fight for less and less land …

This idea is probably more expensive and more difficult than the idea of carving up mountains and dumping them into the ocean. Slowing comets by that much is a lot of work.

[TreacherousCretin]

@choie

I think the guy is hoping for a near-Waterworld type of scenario. Like, one where the very highest elevations are all that are left.

As illustrated by our hero having to dive down several hundred feet (?) to the ruins of Denver. Trouble is, when he resurfaces, why aren’t the nearby Rocky Mountains anywhere to be seen, as they’re still 4-5 thousand feet above sea level.
(It embarrasses me to admit I sat through the whole film.)

[LSLGuy]

Here’s an interesting demonstration of the scale of extra water needed or the amount of hill and valley leveling required to make Earth into (almost) Waterworld.

APOD: 2016 September 11 - All the Water on Planet Earth

[watchwolf49]

@dracoi

This idea is probably more expensive and more difficult than the idea of carving up mountains and dumping them into the ocean. Slowing comets by that much is a lot of work.

Perhaps I should have said bringing in comets that already are slower, like a Mars sized blob in Earth’s orbit and moving just a tiny bit faster … we could see it closely closing in … watch as material starts streaming in … rising ocean levels slowly but surely … so more and more people fight over less and less land …