Sunday, May 28, 2017

Is there anything for simulating the effects of an extreme ice age?

It's relatively easy to simulate sea level rise.  Contour maps are perfect for that.  Want to simulate an X foot rise in sea level?  Look at each "X feet above sea level" contour.  Unless it marks a depression (an area completely surrounded by higher land) that's part of a new coastline.

It's crude, but it'll get the job done.  You get a new map, be it of the entire world or just one part of it, with the new sea level.

It is, theoretically, equally easy to simulate drops in sea level.  You just do the same thing with an ocean floor contour map.  I haven't actually seen any sea level drop maps out there, so I don't know if it's been implemented.

Ice, however, is complex as all fuck.

At first it seems simple enough,  It depends on temperature and precipitation.  Those two things affect each other which is the first complexity that you'll notice, but it's just the beginning.

Salt water, fresh water, dry land, and ice all react to solar heating differently.  And with both kinds of water it also depends on how deep the water is before we get to the wet land beneath it.  That in itself would be an annoying problem to tackle, but temperature and precipitation are as much determined by those things as they are by the movement of the air and water initially heated by those things.

So now we're talking about ocean currents and wind patterns, which are themselves determined by temperature, precipitation, and solid things that get in the way like land and ice.

And just to add some more feedback loops, land and ice are changing this entire time.  That mountain range that was blocking the wind might end up being a non-factor if the ice sheet (a thing known for being flat and non-mountain-like) rolls right over it.  And there aren't going to be any constants in coastal areas because the more ice there is on land the less water there is in the sea, which means more dry land and changing coast lines which is going to change the wind patterns and the water currents and also need to be factored in when thinking about the initial solar heating because as noted dry land does not react to the sun in the same way as sea water.  (Nor as ice.)

And, in short, the whole thing is a massive fucking headache.

But I very much want to be able to get some kind of simulation, however rough, of "drop the temperature/solar output by X and the world looks like Y with the ice sheet being Z thick at [point on ice sheet you clicked on]" for . . . reasons.

Good reasons?  Of course not.  Just reasons.

And I'm pretty sure no such thing exists, but considering that we haven't had a snowball earth in a long time it's not like I can just look up historical recreation maps and see various levels of extreme ice age with the continents in their current positions.

And that's annoying.


  1. I would assume something like this does exist because I've worked with people whose research required analogous models. That was long time ago and it wasn't cheap or simple, but a lot of 3D mapping and modeling, especially when precision isn't critical, has come a long way...

  2. Like, models for specific glaciated areas definitely exist...

    Also I feel like you're kind of underselling the complexity of falling sea levels, which are also part of glaciation...

  3. So, like, mostly people are trying to do the opposite of what you're proposing: predict glacial loss and sea level rise and related climate effects based on temperature changes, etc.

    Like these people:

    But since they're trying to do it with the continents we have, a simplified version of that type of predictive modeling run in the opposite direction would do some of what you want, no?

  4. Related and cool tho prob not useful:

  5. So, what do you want this for? Cause maybe you could combine what's known about the Pleistocene and what's known about Snowball Earth into one picture?

    1. Basically what I want it for is so I can understand a setting for a story I'm doing. If 2/3rds of the earth's surface is covered in ice, which two thirds is it? not like I can just have "above and below these latitude is ice" because ice ages don't work that way.

      Where does the ocean ice end and the open water begin, which places have ice sheets, and how thick, as opposed to places with similar temperature but no ice sheet, what areas have mountains poking through?

      All of it matters for what the characters face. The first thing that matters is when one considers the question of where wildlife can be found, but it also matters what was never iced over, what was and stayed that way, what was and receded, and, also where are the hell are the coastlines now?