Talk:Snowball Earth/Archive 1

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Archive This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Contents

Semi protection

This page should probably be semi-protected since it is now linked by slashdot, a few minutes ago the article had some rather obvious vandalism. --Lehk 05:05, 6 November 2006 (UTC)

I just put in a request for protection. Hope it sticks ~~ Papeschr 05:19, 6 November 2006 (UTC)

last para

There is probably a more cautious way to word the last paragraph of the Snowball Earth discussion. The anamolous equatorial glacial deposits can be accounted for either by a high axial tilt for the Earth (What untilted it?) or by a lesser tilt in the axis of the magnetic field combined with a "normal" glaciation. Someone reported a very high rate of N/S continental motion in the lower Cambrian a few years ago -- which should make one wonder if just maybe the magnetic field wasn't wandering a bit back then.

How about "Competing theories to explain the presence of "equatorial" glaciers explain the phenomenon by assuming that the Earth's axial tilt at the time was roughly 60 degrees or that the magnetic poles used to determine ancient latitudes were wandering further from the physical poles than at later times."

I have problems with the last paragraph too, which describes the Big Tilt theory as "less radical". Gabrielle Walker's book clearly shows that the Tilt theory is as radical (or even more so) than the Snowball Earth theory, so I am removing the "less radical" bit. --kudz75 00:00, 1 Sep 2004 (UTC)

Ice on the equatorial continents...

If the earth's climate became even colder than it was during recent glacial maxima, continental glaciers would, of course, spread equatorward in Europe, North America, New Zealand and Chile.

However, evidence from recent ice ages suggests that there is no way North and East Asia (except for Kamchatka) would ever develop continental glaciers under present continental locations. This is because, if the earth's climate became even colder than it was during the Kansan Glaciation, the factor that has constantly prevented continental glaciation in Asia throughout the Quaternary - lack of sufficient precipitation to feed glaciers - would be expected to continually intensify a s the oceans cooled.

Thus, if significant cooling beyond the level of Quaternary ice ages did occur, large areas of the high latitudes would become so dry they could never form glaciers no matter how cold the climate becomes (as with Siberia and Manchuria throughout the Quaternary). Moreover, there is e vidence that starvation would cause retreat of ice sheets on their poleward sides even if they advanced much further equatorward than they ever have in the Qua ternary.

If we take this to its logical conclusion, we would have ice sheets spreading constantly towards the equator on both sides as the climate became colder, but retreating on their poleward sides as they were increasingly starved of snow. Eventually, we would have ice only in the lower latitudes where precipitation - even if enormously reduced - was still highest and sufficient to feed ice sheets. At the same time, the high latitudes, even if unimaginably cold, would receive absolutely no precipitation and would thus not be able to maintain or develop glaciers.

Does there exist an obvious refutation of this logical idea??

  • IANAPC (I am not a palaeoclimatologist), but at least a few theories about Snowball Earth say that such a thing might not happen after all -- you'd just get frozen wasteland instead. It would still be intensely cold, but my understanding is that you don't actually achieve total glaciation until the warming process begins. Then I suppose it's like frost collecting on a package of food that just came out of the freezer -- the temperatures are still cold, but now there's free water vapor in the atmosphere to freeze in places that hadn't seen glaciation during the deep freeze. Either way, it still represents an essentially uninhabitable world, but if you can stick it out another couple thousand years after the frost starts forming you can at least make it to the next interglaciation phase. That's the part where the temperature spikes horribly and the atmosphere boils you alive with humidity. Haikupoet 4 July 2005 05:02 (UTC)
The unique feature of the last snowball earth was that all continents were loacted near the equator. So the global ice age could not have started from the poles with glaciers. Something different needed to have happened to trigger snowball earth:
  • A good candidate for an inititial trigger is also in this case a sudden decrease of atmospherical methane to near zero as it is today during that peroid (methane did not disapear fully at earlier times and some theories suggest that every global ice age was triggered by a sudden reduction of methane).
  • As the poles were large oceans the global ice age must have started with swimming ice fields growing from sea water at the poles. Perhapes two incredible strong west wind zones isolated and blew together these ice fields (that slowly rotated around the poles). A regional climate isolation due to the west wind zone can be seen today quite weak at Arctica and strong at Antarctica as the southern west wind zone is much more stronger than the northern one because there are almost no continents that could decrease the wind, see Roaring Forties).
  • After the ice fields were large enough to increase albedo of earth enough a runaway global ice age started with quick glacification of the equatorial continents (which might didn't have a large temperature impact until that time due to the climate isolation of the poles).
  • After this the sublimation you mentioned did happen. Ice sublimed at the the poles but new sea water did freeze out at the bottom of the swimming ice shield, So unless the oceans did not freeze to the ground at the poles the water could have flown back from equatorial regions at the ground of the oceans. And if the pole oceans would have freezed to the grounds the reduction of the ice shield would have stopped at that point were the reduced ice mass again did swim up.
  • So these ice free frozen regions could only exist at the continents and probably did exist there.
One remaining question is the methane trigger. In early times the sun had a radiation that was only 60% of today. CO2 alone did not warm up the earth enough so when evolution developed methane producing bacteria (Archaea) life now had better living conditions so evolution forced life to produce methane up to a certain level. However the sun slowly increased and stil increases its radiation during its main branch life cycle (see Hertzsprung-Russell diagram and Sun) but so slowly that it has nothing to do with current Global warming. When the sun increased it's radiation the methane concentration could decrease the same time (as life has best living conditions at medium temperatures it will happen due to evolutionary forces; so the Gaia theory although a little bit strange at the first sight is not that far from what happend. Completly of-topic side notice: Perhapes ID and creationist people should read some books about that; They would understand what a brilliant and beautifull miracle evolution is and this beauty of life as hyperorganism could be seen as sign of god and a deep gratefull feeling of beeing an integral part of our beloved blue planet earth and start giving respect for all parts of this hyperorganism we depend on). When the photonsynthesis was invented by cyanobacteria a problem did come up: The produced Oxygen waste was a strong poison for ancient life. So from time to time life shifted away from the self produced climate equilibrium and the methane producers were killed by increased oxygen production. Now methane suddenly decreased in atmosphere and the whole ice age process started. After vulcanism finally did an end to a global ice age the methane producing life and the oxygen producing life again settled around a new equilibrium at medium temperature. After the last ice age the new equlibrium was that methane producing life had "lost" and from now on CO2 alone was enough for having medium temperatures. As oxidating carbon with oxygen results in much energy it is no coincidence that after the last global ice age higher animals could expanded at the Cambrium (although they perhapes existed in small niches before) as the oceans were now almost completly aerobic. So since the last global ice age we live in a CO2 driven climate were the CO2 gets slowly reduced by natural erosion and washing out processes when sun increases its radiation. This period will end in about 400 Million years when CO2 concentration for producing medium temperature reaches zero. So there will be a new fundamental change eliminating todays life (especially plants and animals, which do depend on CO2) and giving space for new life of a last hot peroid which will finally end life on earth (in about 2 Billion years) long before sun expands to a red giant (which will hapen in about 5 Billion years). Arnomane 17:55, 20 November 2005 (UTC)

Distracting blank spaces

Formatting that encases the framed table of contents in text, in just the way a framed map or image is enclosed within the text, is now available: {{TOCleft}} in the HTML does the job.

Blank space opposite the ToC, besides being unsightly and distracting, suggests that there is a major break in the continuity of the text, which may not be the case. Blanks in page layout are voids and they have meanings to the experienced reader. The space betweeen paragraphs marks a brief pause between separate blocks of thought. A deeper space, in a well-printed text, signifies a more complete shift in thought: note the spaces that separate sub-headings in Wikipedia articles.

A handful of thoughtless and aggressive Wikipedians revert the "TOCleft" format at will. A particularly aggressive de-formatter is User:Ed g2s

The reader may want to compare versions at the Page history. --Wetman 19:54, 9 August 2005 (UTC)

Chaos: Making A New Science

This name does not violate guidelines as Chaos is not an interlanguage link code. However, I only linked it because other places have linked that article title as well. Laundrypowder 01:41, 29 August 2005 (UTC)

You are probably correct that the colon would not have been a problem here. However, I would still question linking it. Doing so means that you think that a Wikipedia article should be written solely about that book, independent of its author. I don't think this book is that notable, unlike other literature. — Joe Kress 04:28, August 30, 2005 (UTC)
  • Yea, well now that I'm back online I was thinking about finding the other links and removing them too. I definately don't have a problem with your change. Then again, everything is wikilinked on here... Laundrypowder 04:45, 31 August 2005 (UTC)

Isotopes

"lighter isotopes are preferentially used in chemical processes,"... As this stands most readers would assume that this is not true of biotic processes. Is this the intention? --Wetman 22:43, 12 September 2005 (UTC)

  • Don't know, but it is worth mentioning that heavy water is slightly toxic precisely because of the presence of deuterium in the molecule... slows down ion transfer or something like that. So it sounds like it's true about biological processes in general. Haikupoet 00:29, 13 September 2005 (UTC)
The section was quite confusing - so I rewrote a bit, hopefully for clarification. I used the book Oxygen: the Molecule that Made the World by Nick Lane as a guide, guess I should add it as a ref. Let me know if I messed it up :-) Vsmith 00:53, 13 September 2005 (UTC)

I don't understand this sentence, what it's trying to say, or how it relates to the section: "The last isotopes are submerged beneath the ocean water sediment." Jonathan Tweet 23:27, 29 April 2006 (UTC)

Nor do I. It was added by an anon about six months ago and simply overlooked since. Removed it as meaningless. Vsmith 01:33, 30 April 2006 (UTC)

Heat radiation

The Earth's radiation budget is balanced by heat radiation, and this article never mentions it. Is the albedo of snow and ice as low in the long-wave region of heat radiation as it is in visible light? If it is, the whole theory collapses because Kirchhoff's law of thermal radiation would require heat radiation to drop by the same proportion as absorbed sunlight. I presume Snowball Earth wouldn't have made Scientific American if that were the case, but I think we should explain why not. The first external link dismisses the subject with this sentence: "Earth's surface emits radiation at longer wavelengths (infrared), balancing the energy of the radiation that has been absorbed." That's more than Wikipedia says about it. Art LaPella 23:31, 16 October 2005 (UTC)

the graph on the right

the graph on the right says "period" - what period? this needs fixing, I think, but I don't know how

The Tonian, Cryogenian and Ediacaran periods. The word "period" is next to a pink square, that corresponds to the pink rectangles in the graph. The green representing the Snowball Earth means that it supposedly occurred at the end of the Cryogenian and beginning of the Ediacaran period. Art LaPella 05:03, 17 October 2005 (UTC)

Snowball Earth vs. Ice age

What's the difference between the Snowball Earth Hypothesis and the ice age that has occurred at the time of the woolly mammoths? Are they related? Snowball Earth Hypothesis 02:06, 12 February 2006 (UTC)

Snowball Earth is just a case of runaway glaciation. The difference is largely a matter of magnitude. Haikupoet 03:18, 12 February 2006 (UTC)
SE is much more poorly know, though. Evidence from that far back is thin. People don't even agree if all the oceans were ice-covered or not. William M. Connolley 11:30, 12 February 2006 (UTC).

Graph on Right

I think the graph should list the most ancient time on the bottom, and the most recent on top, as per standard palentology.

Y Done | Verisimilus T 11:03, 26 April 2007 (UTC)

Neoprotozoic

In this article, it is stated that this event took place in the neoprotozoic, but in the book "Earth: Portrait of a planet" 2nd ed. by Stephen Marshak page 714, this is said to happen in the late protozoic.

Late=more recent=neo. All much of a muchness. --Wetman 16:08, 4 June 2006 (UTC)

Hypothesis Regarding the Survival of Aerobic Life

When I read the portion of the article relating to the question of how aerobic life could have survived such a period of extreme glaciation, a thought occured to me.

I am not an expert on the subject, but it seems to me that "hot spots" such as the ones that have created Yellowstone and the Hawaiian island chain might very well keep significant areas safe from glaciation, and create viable 'islands' of life on our planet.

I am putting this idea in the discussion section because, as a layman, I do not feel confident enough to put it in the article. However, I hope someone more qualified sees it and, if he agrees, puts my hypothesis in the article proper; and, if he disagrees, puts it in the article and then shoots it down with cold hard reasoning.

This is a thought that I've had in the past; however 'hotspots' relate to hot mantle (i.e. the sub-crustal layer of the Earth) which doesn't correspond to hot water overhead. Its effects are limited to producing volcanism; sub-glacial volcanoes could maybe keep small portions of surface water liquid but the tiny area and fluctuating temperature would mean that it wouldn't be a 'large warm sea'... Sorry if that's a badly worded explanation but I hope you get my drift | Verisimilus T 11:06, 26 April 2007 (UTC)

Writing Style

I really feel the writing style needs to be simplified. The Overview section seems clumsy to me. The following sentence is an example of such. One suggestion is that normally, as the ice spread, it would cover some of the land, and so slow the carbon dioxide absorption, and so increase the greenhouse effect, as volcanoes continue to emit carbon dioxide, and the ice spread would stop; but with all the continents clustered along the equator, this would not happen until the freezing process had run away. Also, what is the difference between 'mya' (million years ago) and 'Ma ago' that is being used here?—Preceding unsigned comment added by Eurolymius (talk • contribs)

As can be seen on mya (unit) and mega annum, they mean the same thing. However, Ma is becoming more 'fashionable' (similar to bce for bc and ce for ad).--Karnesky 03:30, 11 August 2006 (UTC)
I've cleaned up that passage, so will remove that tag. --Karnesky 19:15, 26 September 2006 (UTC)

POV

As the opponents of Snowball Earth and their arguments are not mentioned, this article is POV. That said, I do not understand why the two templates are on top of this page. This is definitely NOT a good, unbiased article yet!! Woodwalker 15:09, 20 September 2006 (UTC)

Delisted GA

First of all, there's only four references, three of which aren't inline, and the fourth only referencing one itsy bitsy factoid about a single article in the Scientific American newsletter thing. How is a reader supposed to know that the other three references actually cover everything in this article, it's filled with all sorts of information which really shouldn't just be taken for granted. Secondly, you've got that cleanup tag up there, and while that doesn't really affect the GA criteria unless the article actually, you know, needs cleanup, so that needs to be resolved somehow. And finally, I can't see any sign here that the article was reviwed in the first place, and so in the end, I am removing this article's GA status. Homestarmy 18:29, 26 September 2006 (UTC)

  1. Is your objection the lack of references, the lack of inlining, or both? Can you please put citation-needed tags where you think is appropriate?
  2. The cleanup tag was added in this edit. The user has very few contributions & I've addressed the specific points in what he posted to the talk page.
  3. The GA was added in this edit. I can also find no discussion.
-Karnesky 19:31, 26 September 2006 (UTC)
Fortunately there's no deadline for making this an acceptable "Good" Article. --Wetman 08:06, 27 September 2006 (UTC)

List of doomsday scenarios

Could use votes to save this article, thanks MapleTree 22:35, 28 September 2006 (UTC)

Slashdotted

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