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Creation of a Snowball/Slushball Earth
gloomy forest rain
becomes wrote in little_details
Setting: This is a futuristic Earth-like planet inhabited by a space-faring human-like race.

Search terms: ice age causes, snowball earth, slushball earth, snowball earth causes. I've been reading about space clouds, silicate weathering, and the lowering of greenhouse gases, but I'm not sure I fully understand them.

Situation: I have a planet that I need to turn into a snowball or slushball—that is, nearly the entire surface of the planet must be frozen at the same time. However, I need for someone to cause this change intentionally, and it needs to happen rapidly, if possible in under ten years. The science can be fuzzy and imaginary technology is absolutely allowed.

1) How can I turn this planet into a snowball/slushball using some kind of technology?
2) What sort of technology could that be? (Something invented would be best.)
3) What's the shortest amount of time in which this could happen?
4) What is a simple but scientific explanation for this process? (I don't need to provide hard scientific evidence.)

Thank you in advance. :)

I had no idea what this question was about, but thank you Google:

Oops, sorry. I put the link in the post.

Not sure what sort of technology would fit your world best, or how long you want the snowball to last, but I do recall reading that once you get permanent ice down to a certain latitude, a feedback loop will set itself up and do the rest. This is the albedo-temperature feedback effect.

Since you aren't operating on Earth, check your continent placement. Snowball Earth happened at a time when there were no landmasses over the tropics to divert warm currents poleward. You might have conditions ready for a slight shift in temperature to freeze everything for eons.

Ideas about terraforming Venus might help, since Venus would need to be drastically cooled in the process. This one suggests putting a cloud of crystalline light-reflectors in a ring around Venus, to block sunlight. It's using a timescale of 1000 years, but some of that is in getting our tech up to par and mucking about with atmosphere and rotation.

For shortest amount of time this cooling could happen in... volcanic cooling, caused by atmospheric ash blocking sunlight, is extremely fast. Krakatoa, when it erupted in 1883 and possibly in 535, caused global chaotic weather (droughts, summer snowfall, etc.) and crop failures in 535-536 and 1883-1888. A similar eruption of Tambora in 1815 caused 1816 to be named The Year Without A Summer.

Hope this helps! ^_^

I'll have to read up on continent placement. That could be really useful.

That information about terraforming Venus is fascinating, too.

I'd considered a volcanic eruption as a possibility, or maybe an impact winter, as the start of it. I'll have to look into that some more.

It does help. Thank you! :)

My first thoughts were volcano, asteroid impact, and nuclear weapons. Glad to see someone agreeing.

If the planet's currently Earthlike, changing it that dramatically that quickly will require Sufficiently Advanced Technology; there's no feasible terraforming concepts out there that don't work on much larger timescales. When it happened to ours it did so over at least millenia.

Volcanic or nuclear winters will cool things for a few years, but nothing even slightly close to that unless they were intense enough to aerosolize the top yard of topsoil across the entire planet or something (at which point you've got other problems). If someone wanted to do it that quickly, they'd basically be flipping a switch speedwise and might as well have the capability to shift the planet to a colder orbit or something.

Well, I can use any Sufficiently Advanced Technology that I can make up. That's not a problem.

I might have to see if I can use a volcanic eruption. Nuclear winter won't work. And I don't want to kill everyone, so I guess I have some thinking to do.

Thank you.

There's a couple things that might do. One would be a hand-wavey tech solution to reducing greenhouse gases that goes too far, takes too much CO2 and methane and etc. out of the atmosphere of a civilization that's got a bit too oil-reliant, as we have. (We currently have a number of different tech ideas for doing this, such as injecting CO2 down wells, but none of them would be this severe by themselves--the iceball flks might have done a combination that had unexpected runaway consequences of some kind.) That could be mild the first 30 years and rapidly get bad, growing more stable once the very deep ocean currents stabilize the carbonate acid/base balance they're carrying.
Another one would be a serious asteroid hitting us which ends up changing our orbit outward very slightly, also knocking sun-blocking debris into the atmosphere. Problem with this one is how difficult it would be to have people survive this, as it'd probably kill 95% of land plants and animals and a great deal of sunlight-dependent kelps and corals and plankton. This might need something like returning colonists from some other planet coming back to a wasteland.
And finally, any nasty one-two-three combo of any of the suggestions made so far.

Edited at 2014-05-02 07:12 am (UTC)

That hand-waving is probably my best option. I'll have to look into it. Thank you!

I'm mildly surprised that nobody has suggested the simplest answer of all: Put a big "sunshade" between the planet and its star, that blocks all incoming light.

The technology you'll have to handwave into existence is fairly simple to gloss over: What it takes to make a planet-scale umbrella, what it takes to keep such a large man-made structure from breaking up, and what it takes to keep it in orbit between the planet and its star. The heat that does escape from the greenhouse effect (and there is some, even on Venus) would never be replaced, leaving the planet to steadily get colder.

The deaths from this would all be indirect: Lack of light would lead to crop failures (which could only be partially offset by grow lights, even if those are suddenly put into crash production), plus the cold.

Yes. This is perfect. Thank you so much.

Added bonus (or caution): If the light is blocked off for long enough, you'll have more than an ice age; you'll have to need to go outside for a pail of air every so often.

Depends on how completely it's blocked. If the sun-shade is just partial, it could lead to a lot of cooling but not get all the way to bucket-of-air territory, no matter how long it stays there.

Thanks for the tip. I'll have to make sure it's partial then.