|WikiProject Environment / Climate change||(Rated Start-class)|
These arguments for and against are arguments to the argument. How about just letting the theory be described and arguments for it rather than judging that it exists? There are a great deal of opinions that exist in the world for which there is no cogent proofs. That the argument exists should not force the argument itself to be denied, pithy characterizations like "hot air," "junk," and "wacko" are mere name-calling rather than logical argument. —Preceding unsigned comment added by 220.127.116.11 (talk) 07:25, 26 December 2007 (UTC)
This article is currently a disaster, and is apparently based entirely on two popular books, neither of which sounds reliable (Avery/Singer is definitely junk (Note: Is This a weasel?)) William M. Connolley 10:21, 22 August 2007 (UTC)
- Agreed, but in its defense it's a brand new article, and new articles always have kinks that need to be worked out. (I hope you don't mind, but I added the above section title here.) I suggested some references to Ugajin (talk) earlier because he was still working on it and I don't have time to thoroughly research and work on this article right now:
- Note that the second link above points out that Bond and others don't think the cycle casts any doubt on anthropogenic global warming, which is not clear in the article as it is currently written. Some more information on problems with the cycle and the disputed claims regarding it would give a more balanced article.
- The "timeline" is hard to follow as well, and it would probably be better as a graph with some real data in it so people can easily see size and consistancy of the cycle, both in the North Atlantic and globally. If it is kept as a list then WP:LIST should be followed, including the points about providing references and no original research for the list.
- Some other problems: 1) someone should make sure the lead section follows the guidelines in WP:LEAD, 2) phrases like "Some climatologists and climate modelers argue..." and "Global warming skeptics have ... argue[ed]..." should be avoided per WP:WEASEL, 3) the article has no sections, 4) references could be improved by using citation templates, and 5) the "but the hypothesis itself exists independent of political considerations" line seems unclear and confusing (is it merely stating the obvious or is it trying to say the hypothesis has support from both sides? Even if it's the latter, different conclusions are still drawn by both sides.). -- HiEv 23:08, 22 August 2007 (UTC)
- One further reference:
- Note that on page 4 when discussing Dr. Bond's 1,500-year cycles it says:
- While offering a useful basic framework, this pattern alone does not account for all aspects of past fluctuations and thus is not a sufficient predictor for the future. For example, we usually think of cycles as having a regular, bell-like shape. But during the millennia corresponding to the last ice age, Bond's 1,500-year cycles were closer to rectilinear, indicating sudden starts and stops. As is clearly recorded within the deep layers of Greenland's ice, the transitions often took just a few decades. This abruptness was especially pronounced as the climate warmed. Has this also been the case during our own epoch, the Holocene? If the Holocene's "Bondian" cycles, too, have been rectilinear, one would expect the post-Little Ice Age warming to have been completed within a few decades. One would also expect that in the absence of the Industrial Revolution, global temperature would have stabilized for a warm plateau of several hundred years. But in fact, global temperatures in the decades immediately after the Little Ice Age did not simply jump to a new plateau.
- This seems to suggest that the cycle's pattern may have changed again since the Little Ice Age and it makes it clear that other factors are also (if not more) important. -- HiEv 23:49, 22 August 2007 (UTC)
- Thanks. Unfortunaely this stuff has got emboiled in GW politics, in that some wackos have taken it up as the explanation for the current warming.  is this category. Notice taht with the implausible events removed, there are very few "events" within the holocene William M. Connolley 08:37, 23 August 2007 (UTC)
- No problem and I agree. While the evidence somewhat supports such a cycle for some of Earth's recent history, it does not refute the overwhelming evidence of anthropogenic global warming. (And the cycle certainly isn't "unstoppable" as Avery and Singer claim.) Still, you should probably refrain from using words like "wackos" here since that may be seen as a personal attack. -- HiEv 23:57, 23 August 2007 (UTC)
Never edited a wikipedia page; don't think I'll start. None of the ice cores actually exhibit a 1500-year cycle. They only exhibit a 1500-year pacing, that is, D-O events tend to come in multiples of 1500 years. This is a pattern typical of stochastic resonance. This article also appears to confuse a Bond cycle (sets of progressively colder D-O events that terminate with a Heinrich Event) with Bond's 1500-year cycle. These are two different things. Bond's 1500-year cycle refers to the percentage of hematite-stained quartz and feldspar grains eroded by glaciers and deposited in the North Atlantic as ice-rafted debris (IRD), that is marine sediment cores, not ice cores. Somebody (other than me) might want to highlight this in the article. To find an excellent reference, using google scholar search for 'schulz 2002 1470'. This will explain the pacing v. cyclicity issue as well as why GISP2 exhibits a 1500-year periodicity in it's Delta O-18 power spectrum (giving great insights into the nature of time series analysis). And no, I am not Micheal Schulz. —Preceding unsigned comment added by Bb4r (talk • contribs) 10:47, 13 September 2007 (UTC)
I think the dates should be at least converted to absolute, and the Before the Present stuff dropped, and possibly the BCE just changed to BC. —Preceding unsigned comment added by 18.104.22.168 (talk) 12:42, September 18, 2007 (UTC)
- I can vouch for the fact that Bb4r's contribution above is not from Michael Schulz, for what it's worth, because Michael Schulz would not make the errors it contains! Cycles come in various shapes, not just sinusoidal - eg the 100 kyr cycle is sawtoothed rather than sinusoidal, but is highly periodic. A cycle may be paced or may be stochastic, in which case it would probably be aperiodic, but is still a cycle if it repeats itself. Stochastic resonance means that periodic components can be detected when they might otherwise be missed, thanks to a stochastic "overprint". The Bond cycles are not the same as Heinrich events but are linked to their occurrence in Bond's model. Shulz's abstract - that Bb4r alludes to - includes the remark: " ... This result emphasizes the nonstationary character of the oxygen isotope time series. Nevertheless, a fundamental pacing period of ∼1470 years seems to control the timing of the onset of the Dansgaard-Oeschger events". If Bb4r thinks that ice-rafting events are unrelated to ice sheet history then he/she is in a (very small) minority. Thanks for not interfering with the article, Bbr4. Orbitalforam (talk) 15:51, 25 February 2013 (UTC)
So where does
- ≈2400 BC (Bond event 3) — the Middle Neolithic cold epoch
- ≈3900 BC (Bond event 4) — the Early Neolithic cold event
- You sure you googled it? Try  and  in Google Scholar. —Bender235 (talk) 21:45, 15 May 2008 (UTC)
OK, we're getting better. Now I've removed "cold" from the unknown events, because Bond specifically notes that his events *don't* show up as cold periods in the Greenland cores. He finds them in ice-rafted debris stuff, I think, which isn't known to correlate to temperature. I may have missed something, though, so if you can find Bond calling these "cold" please re-add William M. Connolley (talk) 22:41, 15 May 2008 (UTC)
What conerns me is how these various cycle are so readily discounted as having an affect on our current climate conditions. Loke the North Atlantic oscillation - which doesnt seem to have been factored in either. - Jeremy Cottam —Preceding unsigned comment added by 22.214.171.124 (talk) 12:16, 3 October 2009 (UTC)
Removed image - failed verification
I've removed the graph , which i've tried to verify. Its not from Alley as claimed, and its not from Bond. Please fix up the reference on the image if its to be reinserted. --Kim D. Petersen (talk) 19:39, 2 June 2009 (UTC)
List of events
The list of events looks much like WP:SYN / WP:OR, especially the things associated with the events. Civilisations rise and fall; inevitably, the falls or rises will co-incide with some events. Unless some outside commentator has linked them, we should not William M. Connolley (talk) 21:45, 23 June 2010 (UTC)
- B has restored some of these, uncited, with the edit comment gosh, you're a pain in the neck , which is hardly polite. I've left him a warning on his talk page. The uncited ones are:
- ≈2,800 BP (Bond event 2) — roughly correlates with the Iron Age Cold Epoch (900–300 BC)
- looks dodgy, since  is http://hol.sagepub.com/content/17/2/177 William M. Connolley (talk) 14:30, 8 November 2011 (UTC)
1,800 Yr Lunar Tide Cycle Fits Glacial Data
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=]1,800 Yr Lunar Tide Cycle Fits Glacial Data[/url]. 126.96.36.199 (talk) 07:29, 18 June 2013 (UTC) Alan Lowey
- Unfortunately, Wikipedia is not the right place for original research. Publish a paper, have it go through peer review process, and then come back here. --bender235 (talk) 09:39, 18 June 2013 (UTC)
Bond Events probably not "1500 years"
Hello. While describing these as 1500 ± 500 year events is technically correct, perhaps the article should be edited to reduce emphasis on 1500 and 1470 year cycles and periods. The concept of a 1500 year climate cycle, especially in the Holocene, is dated and inconsistent with recently published work (both for ice cores and ice-rafted detritus). Bond Events appear to be real, but the significance of the timing has been greatly over interpreted due to (at the time unknown) deficiencies in the benchmark chronology.
Scrutiny of a supposed 1,500 cycle increased after the GISP2 ice core chronology was succeeded by the Greenland Ice Core Chronology 2005 (GICC05; e.g., 1). GICC05 does not produce a 1,470 year period, unlike the GISP2 chronology. Also unlike the GISP2 chronology, GICC05 recurrence times of Dansgaard/Oeschger Event are indistinguishable from random (2). Thus discussion on stochastic resonance is no longer really appropriate, unless this article is going to discuss the history of the interpretation of Bond Events.
Reanalysis of the now-available raw data suggests that the ice-rafted detritus records of the last glacial are "an admixture of the ~1000 and ~2000 cycles" and 1500 is the nonexistent mean in a bimodal population (3). For the Holocene ice-rafted detritus data, classical Fourier spectral analysis detects similar 1,000 (Eddy cycle?) and 2,500 year periods (Hallstatt cycle?) (4). Ref 4 also includes wavelet analysis that shows nonstationarity. No statistically significant 1,500 year period is found in the ice-rafted detritus data by Ref 4.
"The North Atlantic ice-rafting events happen to correlate with most weak events of the Asian monsoon for at least the past 9,000 years, while also correlating with most aridification events in the Middle East for the past 55,000 years (both Heinrich and Bond events). Also, there is widespread evidence that a ≈1,500 yr climate oscillation caused changes in vegetation communities across all of North America."
The above paragraph from the current version implies that ice-rafting events are coherent with aridification events at a 1500 yr-1 frequency, but this is not reflected in any of the original references. Gupta et al. Fig S3 wavelet has no 1500-year period. Yang et al. Fig S1 shows no coherency at 1500 years. Bartov et al. don't consider Bond Events (only Heinrich Events). Parker et al. perform no spectral analyses.
The current version also cites Viau et al (2002) for "widespread evidence" of a North American terrestrial 1,500-year oscillation, but the same authors in 2006 (5) state that:
"During the Holocene, climate in North America appears to have varied periodically every ~1100 years rather than the ~1500 year cycle found during the last glacial period. Coherence at frequencies between ~900 and ~1100 years between land, ice, and ocean records suggests a common forcing associated with widespread surface impacts during the Holocene."
TLDR; Considering more recent work maybe this page overemphasizes 1,500 years.
1. Andersen, KK., et.al, 2006. Quaternary Science Reviews 25(23-24) 3246–3257. 2. Ditlevsen, P.D., et al., 2007. Climates of the Past 3(1) 129–134. 3. Obrochta, S.P., et al., 2012 Quaternary Science Reviews 55 23–33. 4. Debret, M., et al., 2007. Climates of the Past 3(4) 569–575. 5. Viau, A.E., et al. 2006 Journal of Geophysical Research 111 D09102
Father Huxleyi 06:48, 20 March 2015 (UTC)