Talk:Dansgaard–Oeschger event

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Reliability[edit]

I'll read the paper tomorrow. For now, my opinion is that relying on *one* paper for information this precise is inappropriate. The text, as it stands on the page, is far too definite. (William M. Connolley 10:19, 6 Mar 2005 (UTC))

Well, the study is about the precision. As for "relying on one paper for information this precise is inappropriate", let's all keep that in mind. Temperature record of the past 1000 years (SEWilco 19:27, 6 Mar 2005 (UTC))

Any plot errors?[edit]

I am far from an expert, so please feel free to point out any egregious errors in the plots and revert if necessary - just trying to inject a little aesthetics. Leland McInnes 08:41, 5 February 2006 (UTC)[reply]

If you mean the first graphics plot, "comparing" the temperatures between Arctis and Antarctis, they in fact contain statistical mistakes, because both the methods and the amplitudes are chosen differently and thus mislead the reader. Notwithstandign this, the conclusion appears to be correct. 2A02:8108:9640:AC3:7D95:52CE:73CD:83A5 (talk) 13:44, 24 September 2019 (UTC)[reply]
Regarding plotting techniques, note that plotting programs cannot read the words "before" or "ago". In these cases the backward data have to get a minus sign. Regrettably the overwhelming majority of our "scientists" are not not even able to handle such programs, with the result that times run differently from one study to the other. And also in this wiki article. A bad sign!2A02:8108:9640:AC3:7D95:52CE:73CD:83A5 (talk) 13:52, 24 September 2019 (UTC)[reply]

Rapidity?[edit]

JimR added:

typically over 1-100 years,

I'm fairly doubtful about this. The gas stuff doesn't have 1y resolution. The isotopes might, in theory, but I don't think they show changes that fast. There is a recent paper (GEOPHYSICAL RESEARCH LETTERS, VOL. 32, L24703, doi:10.1029/2005GL024486, 2005) wot sez:

Extremely rapid fluctuations observed in records of electrical conductivity measurements (ECM) from Greenland ice-cores provoked the idea that the climate system may be capable of flickering between two states during rapid climate transitions. Here it is shown that in general, the flickers seen in ECM records probably reflect the highly non-linear response of electrical conductivity as ice approaches acid/base neutrality, rather than significant changes in the climate system. High frequency, relatively low amplitude changes in chemistry, superimposed upon the broader changes typical of climate transitions would be capable of producing the observed characteristics of ECM records. It must be stated that this result does not detract from the observation of extremely rapid changes in, for example, ice core chemistry and isotopes, which clearly demonstrate that Earth’s climate is capable of very rapid and major reorganisations.

which suggests that some elements of the "rapidity" seen may not be real. William M. Connolley 11:41, 19 February 2006 (UTC)[reply]

The paper William mentions is by Stephen Barker, at [1]. Alley (2000), which I cited in the article, says that the GICP and GISP2 ice-core records "provide annual resolution for some indicators", but also that "The warming as recorded in gas isotopes occurred in decades or less" (in line with William's point about gas resolution being less precise than annual). Alley (2000) also refers to an earlier paper, Taylor et al (1997) Science 278 825-827 The Holocene-Younger Dryas Transition Recorded at Summit, Greenland (free abstract; full text). This does refer to increases in non-sea-salt sulphate and direct-current electrical conductivity over periods of less than 5 years: the Barker article's cautions would seem apply to these measurements. However, Taylor et al also say:
Between 11,645 and 11,612 B.P., there are excursions in delta D, deuterium excess, mean particle size, non-sea-salt calcium, and accumulation that last <5 years.
Aren't these data free of the caveats Barker makes about ECM? -- JimR 01:46, 26 February 2006 (UTC)[reply]

Global synchroneity[edit]

The reference you have just queried (Bond et al. 1999) may have been misapplied in the earlier draft of this article - perhaps it was intended to support a different statement? Verisimilus T 15:09, 6 March 2008 (UTC)[reply]

The trouble i have with the statement, is that from my readings (and i'm just a layman) the D-O events have some indications of having had global impacts, but that its rather uncertain if they were global (ie. if the D-O events where in the NA, then the effects seen elsewhere could be feedback-effects), and i seem to recall that several of the Southern Hemisphere effects aren't syncronous - but rather lag by quite a bit (in some cases).
Bond is a good reference for this article, but in the right places ;-) --Kim D. Petersen (talk) 15:20, 6 March 2008 (UTC)[reply]
A quote from Bond, "temperature variations constrained to the glacial portion of the Greenland ice record", suggests that this certainly isn't the right place to put it! I'll read through and include it. Verisimilus T 18:01, 6 March 2008 (UTC)[reply]

Please consider the following as references for the "citation needed" under Causes.

Cronin, Thomas M., 1999, "Principles of Paleoclimatology," Columbia University Press. p. 462.

Pickering, Kevin T. and Lewis A. Owen, 1994 & 1997, "An Introduction to Global Environmental Issues," Routledge, London. pp. 107-111. — Preceding unsigned comment added by Nhy67ygv (talk • contribs) 04:45, 26 May 2012 (UTC)[reply]

Merge with 1500-year climate cycle[edit]

merge, but without the all the pseudo-science from the 1500 year article. --Kim D. Petersen (talk) 15:24, 6 March 2008 (UTC)[reply]

This seems like a bad idea. For one thing it presupposes that the Dansgaard-Oesger cycles are "Bond cycles in disguise" (a dubious suggestion, as is the supposed equivalence of Holocene Bond cycles with Dansgaard-Oeschger events). For the phase relationship between Antarctic and Greenland cycles, see Blunier and Brook, Science 2001. The direction of causality is not clear from the leads/lags in this study, but the temporal offsets appear to be confirmed by marine records such as MD95-2042.Orbitalforam (talk) 16:56, 12 May 2009 (UTC)[reply]

North Atlantic currents are not a possible cause[edit]

R. Seager has apparently shown that there is no way the shutting down of the North Atlantic current could have driven the Dansgaard-Oeschger event, and changes in atmospheric circulation regimes had to be the driver. See http://www.ldeo.columbia.edu/res/div/ocp/gs/ for his explanation, and links to papers. Gf1605 (talk) 01:05, 6 November 2009 (UTC)[reply]

Role of the Bering strait[edit]

The following news story (and the linked paper at the bottom of that page) may have some "Bering" on the topic:

Johnson, Scott K., "An open Bering Strait blocks off sudden swings in climate", ArsTechnica, retrieved 2012-04-11.

Regards, RJH (talk) 16:40, 11 April 2012 (UTC)[reply]

1,800yr Lunar Tidal Cycle Fits Glacial Data[edit]

I've just made a discovery when using the 1,800 lunar tidal model of arctic environment of Northern Russia during the last 20,000yrs and the assumption of a millennial peak triggering H1 at 17,000 B.P. See 'Radiocarbon Variability in the Western North Atlantic During the Last Deglaciation' (2005) by Laura F. Robinson et al. matched at 10,000 B.P. with the graph in paper 'Holocene Treeline History and Climate Change Across Northern Eurasia' (2000) by Glen M. MacDonald et al.

The Maximum Forest Extension is 2 cycles of 1,800 yrs, showing peaks at 4,400 and 8000 yr B.P. (uncalib) which fits with the lunar tide into the arctic basin cycle and extrapolates to the date of 17,000 yr B.P., the onset of Heinrich 1. The tree data shows dips due to the lunar tidal minimum. The diagram can be seen here [url=http://www.unexplained-mysteries.com/forum/index.php?showtopic=249553&hl=]1,800yr Lunar Tidal Cycle Fits Glacial Data[/url]. 176.24.226.120 (talk) 07:39, 18 June 2013 (UTC) Alan Lowey[reply]

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Causes[edit]

Did none of these "scientists" ever note that the Antarctis, in contrast to the Arctis, rests on a continental shelf, and is surrounded by water, allowing circulations of water streams that obviously have a damping effect on temperature fluctuations.2A02:8108:9640:AC3:7D95:52CE:73CD:83A5 (talk) 14:00, 24 September 2019 (UTC)[reply]

Current DO event?[edit]

Just saw this[2] haven't read it yet (paywalled). reddit thread. 2602:24A:DE47:BB20:50DE:F402:42A6:A17D (talk) 14:50, 9 August 2020 (UTC)[reply]

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