Talk:Ice age

Precise Definition of Ice Age

This article describes an Ice Age as "a geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in an expansion of continental ice sheets, polar ice sheets and alpine glaciers.". I am not a scientist but to mee this definition seems a bit "wooly". What counts as long term? How far should temperatures fall below their "long term" levels before an ice age is identified? What percentage of the earth should be covered in glaciation? etc etc

I was unable to find anything better on the web so it may be that the above description is the scientific consensus, does anyone know? Alternatively perhaps people think this issue is too esoteric for an encyclopedia?

Zanzare (talk) 14:10, 30 December 2009 (UTC)

I don't think there is any need for a precise definition, from a scientific POV. It is just a label (analogy: there was no need for a precise defn of "planet" from a science POV) William M. Connolley (talk) 22:49, 30 December 2009 (UTC)

It is a fuzzy term, though the time-spans are typically millions of years or more. I just made some changes to the lede that will hopefully improve some clarity. Awickert (talk) 23:04, 30 December 2009 (UTC)

While I agree that neither "age ice" nor "planet" would necessarily need a strict definition, we should beware the fate of Pluto.94.220.254.157 (talk) 04:27, 1 March 2010 (UTC)

Pluto is still there. That's the thing about labels, they don't change the facts, they're just useful handles for describing them. Tasty monster (=TS ) 18:49, 20 September 2010 (UTC)

New version

I think it is better and more correct the new version of "Ice age",this one:

"An "Ice Age" or, more precisely, "Glacial Age" is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in an existence of continental ice sheets, polar ice sheets and alpine glaciers.

The Earth's climatic history has been divided, in intervals of millions of years, into Ice Ages and Interglacial Ages. The term Ice Age refers to a long interval of time (millions years) where the Earth's poles are covered with ice sheets more or less extensive and where the average temperature of the poles remains below 0 °C) . The Ice Ages are considered the Earth's climate history "seasons" and they are divided into Glacial periods (or alternatively "glacials") and Interglacial periods (or "Interglacials"). The Glacials are the stages of advancement of the ice sheets (called glaciations) and the Interglacials are the stages of retreat (these periods last for thousand years).

Interglacial Ages last millions of years, when the ice sheets have retreated to a minimum extent at the poles, and they separate two successive Ice Ages."

We should vote to choose the best one.--93.151.235.163 (talk) 10:39, 20 September 2010 (UTC)

No we shouldn't. We should discuss how to improve the article. Tasty monster (=TS ) 18:54, 20 September 2010 (UTC)

Main image of the globe during the ice age

Anyone agree the heading image of the earth seen from space at the height of the last glaciation is not very helpful? I've been trying for fifteen minutes to match it to ordinary geography, that is to grasp from what angle it's supposed to show the earth. I supppose the N Atlantic is at the centre, but the rest? If northern Europe is the big hump on the top right, then what are the big white spots at right centre of the picture? Ethiopia and east Africa? That won't do: those ice sheets were relatively small in extent compared to those in the north. The edge outline of the ice to the left looks strange too. The lack of differentiation between non-glaciated continents and sea is a big drawback - both are shown as simply dark! I've seen much better pictures using the same idea, at the very least this one needs some captioning. Strausszek (talk) 10:03, 20 October 2010 (UTC)

I must say I had the same difficulty, but it became much clearer as soon as I blew it up a bit, when cloud over the oceans seems to become less obtrusive. The image has N at the top; the west coast of West Africa is at the centre, with Europe at upper right, S America creeping into the lower left, N Am upper L, the whole of Africa lower R. The smaller white area I think you mean at about 2 o'clock is I think the Caucasian mountains. The only white in Africa looks like cloud from the original image. More contrast for continents would certainly help at the image size WP users are likely to see it. Richard New Forest (talk) 22:50, 20 October 2010 (UTC)

Hard to believe

The "Sun's orbit around the Galaxy" is mentioned. This seems to refer to the spinning of our Galaxy. This has a period of 250,000,000 years. It is hard to believe that this spinnning is the cause of the ice ages, with much shorter periods. — Preceding unsigned comment added by 93.97.194.200 (talk) 15:30, 15 July 2011 (UTC)

That's because they are wrong, ice ages do not occur more than once in the planet's history. The crystalline structure of a snow ball earth is the moon! The ice-age equates to a day of brama, therefore every 26,000 years the earth enters 'extremities' which cause evolution to take over. This 2012 prophecy? Is just another set motion for the poles to change and the planet to under go extremities until the planet dies. True, there are polar tilts when the planet gets cold, but that's new compared to its age and has nothing to do with magnetism. What you are trying to comprehend is Kali yuga, which we are also in, basically the sun is turning direction or curving. We are still in the ice-age so to speak. Heat escapes, planets condense, oceans spread and contract, deserts arrive, Truth hurts. Later.--69.255.42.105 (talk) 23:59, 31 October 2011 (UTC)

Overly Long Paragraphs

Some of the paragraphs in the article are way too long, which adversely affects readability. That's bad writing for for all but very advanced literary writers, who can sometimes pull it off. Most writers should instead break larger paragraphs into smaller ones. Especially in articles for wide public consumption.

69.171.160.110 (talk) 02:24, 27 September 2011 (UTC)

Criticism about Ice Age Theory & Alternative Theories

Not all people are convinced by the Ice Age, there are certainly scientists who belong to the "there is no ice age" camp. Anyone know anything worth mentioning about them? PhilaSiti —Preceding undated comment added 13:33, 29 October 2011 (UTC).

I am one of the many. It began as a theory postulated in 1836 by a Swizz naturalist called Louis Agassiz and has become enshrined as "scientific" dogma. This theory has been pulled to pieces so many times, most especially because so much has been found that questions it, even flatly refutes it, yet is still clasped to the bosoms of all conventional scientists. A constant situation throughout all the sciences. It's a wonder we get anywhere at all. (Here's to the renegades, who so often turn out to be right after living lives of ridicule.) To the average person, they've been taught it all their lives and just take it for granted. But the most telling argument against is that no one has ever, not once, come up with a convincing reason for why any such thing ever happened in the first place. Try reading Allan & Delair's Cataclysm, the heavily researched and compelling evidence against ice ages. You may not believe (as I do) in their postulated world flood, but you'll find the ice age idea shattered.Stellabystarlight (talk) 20:29, 20 November 2011 (UTC)

If you have something to say about the article or improving it with any sources, then bring it up. I don't think rants or soapboxing/preaching are allowed ont he talk pages. You aren't talking about the articleBunser (talk) 20:33, 20 November 2011 (UTC)

If you're interested in the causes of ice ages, then Ice_age#Causes_of_ice_ages is the place to start. As for scientists who don't believe they existed - that is a new one on me. Got any decent refs? William M. Connolley (talk) 21:53, 20 November 2011 (UTC)

Of course I'm talking about the article. And this isn't a rant. I can do a rant and this isn't one of them. Also it's in answer to someone's question. As for adding to the article, I have no doubt it would be removed, so why bother? Dogma is dogma.Stellabystarlight (talk) 21:10, 20 November 2011 (UTC)

That was more than a decent reference. And it itself is referenced by enough books, articles, and presented papers to collapse a book shelf. J.B. Delair is an Oxford-based geologist. He is also the Museum Curator of Geology at University of Southampton, England. D.S. Allan has since died, but he was Cambridge-based and a science historian specializing in paleogeography, particularly in the Artic regions. Serious and learned questioning of the validity of an ice age or ice ages (it began with only one ice age postulated and has grown like Topsy ever since) has been going on for well over a hundred years. And yes, there are a number of theories trying to prove a cause, but none is without serious flaws, so serious that the whole theory (and it is only a theory) might well come tumbling down in our lifetimes. It also means we do not face another ice age if it isn't true to begin with.Stellabystarlight (talk)

I was hoping for scientific papers, rather than a popular book praised by Atlantis Rising magazine [1]. But anyway: even assuming they were correct, why would event in 9000 BC have any effect on our understanding of the ice-age cycle, which has gone through 8 cycles over the last 800 kyr? We don't face another ice age anyway even on the conventional theory, so that bit is redundant William M. Connolley (talk) 22:58, 20 November 2011 (UTC)

I suppose reading the book (if only the section devoted to the theory of ice ages) would help answer that question rather than just assuming it must be "unscientific" (therefore useless) if praised by something (I'm not familiar with the magazine you've mentioned) you find foolish. (If you do...I really don't know.)Stellabystarlight (talk) 23:46, 20 November 2011 (UTC)

I have read Allan & Delair's Cataclysm!: Compelling Evidence of a Cosmic Catastrophe in 9500 B.C. This book is remarkable for its profound scientific ignorance and illiteracy of Quaternary geology, mechanics of extraterrestrial impacts, sedimentology, taphonomy, and geology in general. There are Young Earth creationist publications that exhibit a better understanding of basic geology than this book does. For example, this book argues that Pleistocene glacial tills were not deposited by continental ice sheets. Despite the overwhelming sedimentological evidence to the contrary, this books argues that what Earth scientists agree to be glacial deposits are instead impact ejecta from an extraterrestrial impact in 9500 B.C. This book either ignores or dismisses interglacial paleosols, radiometric dating, and other evidence associated with these glacial tills in order to compress the deposits of multiple glacial-interglacial cycles into what it argues to be the deposits created by a single extraterrestrial impact event. In another case, they argue that manganese nodules found on the ocean floor are fragments of the comet that hit Earth and created Pleistocene glacial tills as impact ejecta in 9500 B.C. Also, this book unhesitantly and uncritically uses completely fictional evidence, i.e. the "flash-frozen" mammoths of Siberia, to support its arguments. The entire book uses innumerable misinterpretations, misrepresentations, and selective citation of material culled from the published literature in order to fabricate a case for a terminal Pleistocene extraterrestrial impact-created Deluge. This book is contrived fringe / alternative science at its worst and what geologists regard at its funniest while sharing drinks. Paul H. (talk) 14:31, 13 December 2011 (UTC)