scrape_r_rational/data/cache/2tuqpg.md

Help with global effects of a continent appearing in the Pacific Ocean for a story

Post:

Alright so here's the basic out line. Magical race from another universe is under threat, so they decide to move their entire continent somewhere else. After doing a quick scan of the multivierse they find a planet with similar atmospheric conditions and large bodies of water. Archmages cast the spell and boom multiversal continent transfer complete. (Whether or not moving your entire continent is the smartest move is debatable, since they assume that any world teleport to would not have the plants and such that they could eat, and don't have the time to create a seed bank or something similar.)

Turns out the planet they moved it to is ours, and here's the question. If a continent that was about the size of the continental US (around 8 million kilometers^2 in size we'll say) iterated with the the Pacific plate, displacing (not destroying or converting it) any water and atmosphere, what would the effects be?

I've been able to figure out a rough estimate of how much the sea would rise (its about 95 meters globally, give or take a few meters) but I don't know what effects it would have tectonically or how it might affect weather/atmospheric conditions. Does anyone have a better background in this that might be able to help me out?

Edit: not kilos kilometers, those are rather different

Comments:

• u/alexanderwales:

  That's such an extreme change that I'm not sure existing models are going to help too much. You start off with a tsunami far, far worse than anything in human history, which destroys human civilization as we know it and kills at least half the population, and then the sea level rising floods out every single coastal city.
  
  In terms of weather, it depends on where exactly your continent gets placed in the Pacific. [Check out this XKCD what if](https://what-if.xkcd.com/10/) which goes into some details about how the world would change if it were flipped on its side, since he goes into some detail on how the climate would be affected. Are you placing the continent so that it disrupts the jet streams?
  
  But mostly, any concerns about weather are going to be overshadowed by the fact that your proposed scenario is wiping out a significant chunk of life on earth.
  

  • u/Threedoge:

    And once again XKCD proves to be relevant. Thanks I hadn't seen that one, and yes coastal/near coastal settlements seem to number around a billion individuals, though I still need to see if there is a better way to sample that. And its also the underlying conflict of this story, to see if it would even be *remotely* possible for this group to redeem themselves in the eyes of our populous.
    

• u/eaglejarl:

  I would try submitting this one to What If XKCD. Seems right up Randall's alley. 
  
  I don't know the effects, but some things I'd look for:
  
  * Plagues resulting from the numerous dead bodies where you just killed most of the human race
  * Total collapse of human civilization due to deaths and destruction of infrastructure. 
  * Disruption of ocean circulation leads to temperature changes in the ocean causing massive weather changes and die offs
  * Reduced ocean area means less evaporation there, but other areas are now flooded. Total area to evaporate from has gone up, so the weather gets wetter
  * Depending on [where it arrives](http://www.worldatlas.com/aatlas/infopage/tectonic.gif), the new continent could end up spanning the boundary of two continental plates. This could lead to more vulcanism and might, over geologic time, tear the new continent apart.
  

• u/OffColorCommentary:

  Are you sure you want to displace the water instead of doing some sort of swap?
  
  Without the sea level changes and massive tsunamis, you're still looking at a giant mess.  The new continent will completely change pacific ocean currents.  To get a sense of the scale of what ocean currents do to our climate - England and Siberia have the same latitude.
  
  What the new currents would shake out to after adding a continent is beyond prediction for now.  You can count on ending all the known effects (like the extreme mildness of US's west coast), but there's no telling what new ones we'll get.  I'd bet on warming up Alaska (to England levels) and generally cooling down Australia, but that's a shot in the dark.
  
  Places with sudden warming will experience flooding, and places with sudden cooling will have deaths due to exposure and wide-scaled infrastructure shutdowns (Australia does not have snow plows). Everyone who has crops will lose them, and so many plant species will die off that we might have to start importing ones appropriate to the new climates once things settle down.
  
  But that's all post-change. It'll take a long time to settle all that water into a new cycle, and until it does you're going to have rapid temperature shifts, which means rapid changes in air currents, which means hurricanes and tornadoes.  The eventual power of hurricanes (not tornadoes) will quickly go down since the new oceans will be smaller, but the big ones triggered by the sudden change in equatorial flow will suck.
  

• u/FaceDeer:

  If the archmages know the water's going to be displaced rather than destroyed or "swapped", they'll know that their own continent is going to see major flooding as well. Will they be able to calculate how much by? They could perhaps raise their continent by that amount when they make the transition.
  
  How rapidly is the water displaced? If it's "instant" the resulting tsunami is going to be incredible, will probably kill billions. It'll also screw over the arriving continent, so again, the archmages will need to account for this.
  
  Do they know the destination world is inhabited? If so, they're deliberately making a choice to kill billions to save their own skins. They're going to be seen as history's greatest monsters. Even if it's accidental, expect the whole world to hate their guts. How well does magic fare against nuclear weapons and so forth? Could get reeeal ugly unless they fall all over themselves trying to help fix the mess they made.
  
  Does it overlap any islands in the Pacific? What happens to them and their inhabitants? Probably small potatoes compared to the flooding, but it'll probably matter if they wind up with Hawaii embedded in the middle of their land.
  

  • u/Threedoge:

    In order:
    
    Yes they do know that it would cause some flooding for their land mass, and the intimidate secondary spell that would be cast is one that would basically create large walls of force to create a flood wall around the continent (there will be some flooding because the universal tunneling spell would have to finish first before they could work on the second).
    
    Not instantaneous, I would say about a three day period.
    
    No they don't have a clue that its inhabited. They know that the world has a rich nitrogen/oxygen atmosphere and large bodies of water, and that its in the goldylocks zone. Everything else is a mystery to them.
    
    Yes it would, for lack of a better term, swallow smaller landmasses, though if I'm positioning this thing right it wouldn't eat Hawaii. I think, need to run those numbers again.
    
    And finally yes, what they are doing is going to be considered an atrocity by basically everyone. We're talking about wiping out nearly a billion or so individuals in just the initial floods, let alone what famine/oil scarcity/god knows what else.
    

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