# A question about Snowball Earth: was there enough water? **URL:** \ **Category:** Factual Questions\ **Created:** [February 22, 2012, 10:18am UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621 "2012-02-22T10:18:41Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [February 22, 2012, 10:18am UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/1 "2012-02-22T10:18:41Z")
As I understand it, the Cambrian explosion is supposed to have been preceded by a snowball Earth. This is allegedly demonstrated by there being glaciers at the equator There’s just one thing that puzzles me: was there enough water at the time? There isn’t now. ---
**Author:** ![Anaglyph](https://avatars.discourse-cdn.com/v4/letter/a/ed8c4c/32.png) [@Anaglyph](https://boards.straightdope.com/u/Anaglyph)\ **Post date:** [February 22, 2012, 10:41am UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/2 "2012-02-22T10:41:07Z")
As in milder glaciation events, the larger mass of water present as inland ice would have been compensated by a lowering of the sea level ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [February 22, 2012, 10:59am UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/3 "2012-02-22T10:59:07Z")
> [@Anaglyph](#): > > As in milder glaciation events, the larger mass of water present as inland ice would have been compensated by a lowering of the sea level Which exposes more land. Which needs more water to become ice to cover it. Was there enough water? ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [February 22, 2012, 11:17am UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/4 "2012-02-22T11:17:57Z")
Think of it this way. The earth’s surface is something like 71 percent water. If you took 50 feet of water off of the surface of the oceans, you wouldn’t expose that much land. Cover the entire land surface in 50 feet of ice, and that only takes 29 of that 71 percent. Cover it in another 50 feet of ice (for a total of 100 feet) and you’re up to 58 of that 71 percent. You can use the remaining 13 of that 71 percent to cover newly exposed land (which would be far more than what you need). So you could easily snowball the earth even without a huge drop in ocean levels. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [February 22, 2012, 11:53am UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/5 "2012-02-22T11:53:30Z")
A snowball Earth with glaciers at the equator doesn’t mean the whole planet was covered in ice, any more than the fact that their are glaciers in Sweden today means that all of Sweden is covered in ice. All that a glacier requires to form is sufficient snow and sufficiently low temperatures that it doesn’t melt. You don’t need to cover the entire continent with ice to produce glaciers, just some of the larger valleys. Even today, much of Antarctica isn’t covered in ice, and it sits at the pole. ---
**Author:** ![j\_sum1](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@j\_sum1](https://boards.straightdope.com/u/j_sum1)\ **Post date:** [February 22, 2012, 1:00pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/6 "2012-02-22T13:00:56Z")
> [@Blake](#): > > Even today, much of Antarctica isn’t covered in ice, and it sits at the pole. Sorry, I am going to dispute that. The Dry Valleys are a small proportion of the Antarctic landmass. At the pole the ice is more than 3km thick and IIRC about 80% of Antarctica has been pushed below sea level by the weight of the ice. The thought is that the land would spring back of the ice was ever to melt. ---
**Author:** ![Crotalus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crotalus/32/41_2.png) [@Crotalus](https://boards.straightdope.com/u/Crotalus)\ **Post date:** [February 22, 2012, 1:01pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/7 "2012-02-22T13:01:50Z")
> [@Blake](#): > > Even today, much of Antarctica isn’t covered in ice, and it sits at the pole. Really? I thought Antarctica was over 90% ice-covered. [Cool facts about Antarctica.](http://faculty.umf.maine.edu/gretchen.legler/public.www/antarcticawebsite/coolf.htm) Ninja’d by j\_sum1. ---
**Author:** ![Snarky\_Kong](https://avatars.discourse-cdn.com/v4/letter/s/a183cd/32.png) [@Snarky\_Kong](https://boards.straightdope.com/u/Snarky_Kong)\ **Post date:** [February 22, 2012, 1:55pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/8 "2012-02-22T13:55:48Z")
The surface area of Earth is ~196 million square miles. The total volume of water on Earth is ~330 million cubic miles. Water gains about 9% of volume when it freezes. Taking that excess volume and distributing it over the surface of the planet would result in a layer of ice about 800 ft thick. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [February 22, 2012, 3:02pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/9 "2012-02-22T15:02:38Z")
IIRC, in the last ice age weren’t sea levels down about 300 feet? (Land bridge almost Alaska to Asia?) glaciers a mile thick in some northern latitudes? If instead the snow fell steadily further south as the snow line moved towards the equator, eventually all the land surfaces would be covered. Is it NOT a snowball earth if some places only have 10 feet of snow? Like the real world today or 20,000 years ago or the antarctic, some spots would be bare rock, some would have variable snow cover of feet, some would have feet or miles of ice cover. Depends on weather patterns more than the earth’s water cover. ---
**Author:** ![Tom\_Tildrum](https://avatars.discourse-cdn.com/v4/letter/t/e95f7d/32.png) [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)\ **Post date:** [February 22, 2012, 3:56pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/10 "2012-02-22T15:56:15Z")
As we all remember from childhood, a snowball and an iceball are very different things. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [February 22, 2012, 4:47pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/11 "2012-02-22T16:47:31Z")
Assuming the theory is correct, the land would have been largely covered in snow, but not necessarily to any great depth. Not all of the land would have been under glaciers, there isn’t enough water. This would have had the effect of increasing the Earth’s albedo, so that more of the sun’s energy was reflected into space. Only a thin covering of ice was necessary to achieve this. The Earth might have looked like a snowball with grit in it, please don’t take the term too literally. Note that at the time of snowball earth, all life was contained in the oceans. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [February 22, 2012, 5:06pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/12 "2012-02-22T17:06:33Z")
As has been said, at this point there was no multicellular life on land, and only the beginnings of multicelluar life in the ocean. So it doesn’t matter how extensively the land was covered by glaciers. What matters is the extent of the sea ice. Covering large areas of the ocean with ice means drastically lowered photosynthesis. If you have permanent icecap over the oceans at the equator, then there will be almost no life left on precambrian Earth. The land is a sideshow. I guess I don’t understand the question of whether there was enough water to allow glaciers at the equator. There’s a lot of water on Earth, it’s called the ocean. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [February 22, 2012, 5:52pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/13 "2012-02-22T17:52:59Z")
> [@Alka\_Seltzer](#): > > Not all of the land would have been under glaciers, **there isn’t enough water**. I don’t understand your reasoning for this statement. What are you basing that on? ---
**Author:** ![Svejk\_1](https://avatars.discourse-cdn.com/v4/letter/s/ea666f/32.png) [@Svejk\_1](https://boards.straightdope.com/u/Svejk_1)\ **Post date:** [February 22, 2012, 8:36pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/14 "2012-02-22T20:36:14Z")
> [@Alka\_Seltzer](#): > > Not all of the land would have been under glaciers, there isn’t enough water. > [@Snarky\_Kong](#): > > The surface area of Earth is ~196 million square miles. The total volume of water on Earth is ~330 million cubic miles. Water gains about 9% of volume when it freezes. Taking that excess volume and distributing it over the surface of the planet would result in a layer of ice about 800 ft thick. Reading a thread before posting isn’t such a bad idea you know. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [February 22, 2012, 8:37pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/15 "2012-02-22T20:37:25Z")
> [@ZenBeam](#): > > I don’t understand your reasoning for this statement. What are you basing that on? As you remove more water from the sea, it’s level falls and more land is exposed. There isn’t enough water to bury the existing landmasses in ice without exposing a lot of new land. Glaciation occurs when snowfall exceeds melting and sublimation over a long period of time. As more of the Earth freezes, including the oceans, precipitation would decrease. The air over Antarctica is the dryest on Earth. I don’t see how that could lead to complete glaciation over land. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [February 22, 2012, 8:39pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/16 "2012-02-22T20:39:28Z")
> [@Svejk\_1](#): > > Reading a thread before posting isn’t such a bad idea you know. **Snarky\_Kong** ’s statement about expanding ice isn’t relevant, as the snowball earth theory does not state that all of the water turned to ice. Only the top few meters did, as the Earth’s heat prevented most of it from freezing. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [February 22, 2012, 8:46pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/17 "2012-02-22T20:46:26Z")
> [@Lemur866](#): > > . . . [At] this point there was no multicellular life on land, and only the beginnings of multicelluar life in the ocean. . .. Well, [maybe, and maybe not](http://www.sciencedaily.com/releases/2010/06/100630171711.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29). There might have been multicellular life a billion years preceding Snowball Earth, although it was probably a dead end, and our multicellular ancestors are probably more in the timeline of Snowball Earth. ---
**Author:** ![Svejk\_1](https://avatars.discourse-cdn.com/v4/letter/s/ea666f/32.png) [@Svejk\_1](https://boards.straightdope.com/u/Svejk_1)\ **Post date:** [February 22, 2012, 8:50pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/18 "2012-02-22T20:50:48Z")
What \*\*Snarky \*\*said _is_ relevant (but not even necessary to disprove your point about there not being enough water), but what you are saying is not. The 197 million sq miles includes the sea bed. Obviously, if you distribute 330 million cu miles over 197 million sq miles, that gives you more than 1 mile of ice on every single square mile, seabed and land area alike (I wonder how \*\*Snarky \*\*gets to 800 ft when there’s 5000+ ft in a mile), - and that’s not even taking into account that the 330 million cu miles would expand by 9% as the water becomes ice. That a lower sea level would free up land is not remotely a problem for having a world covered in glaciers. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [February 22, 2012, 8:56pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/19 "2012-02-22T20:56:56Z")
Did you read my point about glaciation and precipitation? The average depth of the ocean is nearly 4km. How exactly does that mass of water get distributed so that all the land is covered in a significant depth of ice? ---
**Author:** ![Svejk\_1](https://avatars.discourse-cdn.com/v4/letter/s/ea666f/32.png) [@Svejk\_1](https://boards.straightdope.com/u/Svejk_1)\ **Post date:** [February 22, 2012, 9:09pm UTC](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621/20 "2012-02-22T21:09:34Z")
Look, I’m just saying that when someone has pointed out that there’s enough water on the planet to cover the entire surface including the seabed with a thick layer, a statement that “Not all of the land would have been under glaciers, there isn’t enough water” just does not cut it. [Next page](https://boards.straightdope.com/t/a-question-about-snowball-earth-was-there-enough-water/613621.md?page=2)