Younger Dryas
The Younger Dryas, which occurred circa 12,900 to 11,700 years Before Present (BP),[2] was a stadial (cooling) event which marked a return to glacial conditions, temporarily reversing the climatic warming of the preceding Late Glacial Interstadial (also known as the Bølling–Allerød interstadial, which spanned from 14,670 to 12,900 BP.).[3] The Younger Dryas was the most severe and longest lasting of several interruptions to the warming of the Earth's climate. The end of the Younger Dryas marks the beginning of the current Holocene epoch.
The change was relatively sudden, took place over decades, and resulted in a decline of temperatures in Greenland by 4–10 °C (7.2–18 °F),[4] and advances of glaciers and drier conditions over much of the temperate Northern Hemisphere. A number of hypotheses have been put forward about the cause, and the hypothesis historically most supported by scientists is that the Atlantic meridional overturning circulation, which transports warm water from the Equator towards the North Pole, was interrupted by an influx of fresh, cold water from North America into the Atlantic.[5] However, several issues do exist with this hypothesis, one of which is the lack of a clear geomorphological route for the meltwater. In fact, the originator of the meltwater hypothesis, Wallace Broecker, stated in 2010 that "The long-held scenario that the Younger Dryas was a one-time outlier triggered by a flood of water stored in proglacial Lake Agassiz has fallen from favor due to lack of a clear geomorphic signature at the correct time and place on the landscape".[6] A volcanic trigger has been proposed more recently,[7] and the presence of anomalously high levels of volcanism immediately preceding the onset of the Younger Dryas has been confirmed in both ice cores[8] and cave deposits.[9]
The Younger Dryas did not affect the climate equally worldwide, but the average worldwide temperature changed drastically. For example, in the Southern Hemisphere and some areas of the Northern Hemisphere, such as southeastern North America, a slight warming occurred.[10]
The Younger Dryas is named after an indicator genus, the alpine-tundra wildflower Dryas octopetala, as its leaves are occasionally abundant in late glacial, often minerogenic-rich sediments, such as the lake sediments of Scandinavia.
General description and context
The presence of a distinct cold period at the end of the Last Glacial Maximum has been known for a long time. Paleobotanical and lithostratigraphic studies of Swedish and Danish bog and lake sites, as in the Allerød clay pit in Denmark, first recognized and described the Younger Dryas.[11][12][13][14]
The Younger Dryas is the youngest and longest of three stadials, which resulted from typically abrupt climatic changes that took place over the last 16,000 years.[15] Within the Blytt–Sernander classification of north European climatic phases, the prefix "Younger" refers to the recognition that this original "Dryas" period was preceded by a warmer stage, the Allerød oscillation, which, in turn, was preceded by the Older Dryas, around 14,000 calibrated years BP. That is not securely dated, and estimates vary by 400 years, but it is generally accepted to have lasted around 200 years. In northern Scotland, the glaciers were thicker and more extensive than during the Younger Dryas.[16] The Older Dryas, in turn, was preceded by another warmer stage, the Bølling oscillation, that separated it from a third and even older stadial, often known as the Oldest Dryas. The Oldest Dryas occurred about 1,770 calibrated years before the Younger Dryas and lasted about 400 calibrated years. According to the GISP2 ice core from Greenland, the Oldest Dryas occurred between about 15,070 and 14,670 calibrated years BP.[17]
In Ireland, the Younger Dryas has also been known as the Nahanagan Stadial, and in Great Britain it has been called the Loch Lomond Stadial.[18][19] In the Greenland Summit ice core chronology, the Younger Dryas corresponds to Greenland Stadial 1 (GS-1). The preceding Allerød warm period (interstadial) is subdivided into three events: Greenland Interstadial-1c to 1a (GI-1c to GI-1a).[20]
In addition to the Younger, Older, and Oldest Dryases, a century-long period of colder climate, similar to the Younger Dryas in abruptness, has occurred within both the Bølling oscillation and the Allerød oscillation interstadials. The cold period that occurred within the Bølling oscillation is known as the intra-Bølling cold period, and the cold period that occurred within the Allerød oscillation is known as the intra-Allerød cold period. Both cold periods are comparable in duration and intensity with the Older Dryas and began and ended quite abruptly. The cold periods have been recognized in sequence and relative magnitude in paleoclimatic records from Greenland ice cores, European lacustrine sediments, Atlantic Ocean sediments, and the Cariaco Basin, Venezuela.[21][22]
Examples of older Younger Dryas-like events have been reported from the ends (called terminations)[a]
of older glacial periods. Temperature-sensitive lipids, long chain alkenones, found in lake and marine sediments, are well-regarded as a powerful paleothermometer for the quantitative reconstruction of past continental climates.[25][page needed] The application of alkenone paleothermometers to high-resolution paleotemperature reconstructions of older glacial terminations have found that very similar, Younger Dryas-like paleoclimatic oscillations occurred during Terminations II and IV.[a] If so, the Younger Dryas is not the unique paleoclimatic event, in terms of size, extent, and rapidity, as it is often regarded to be.[25][26] Furthermore, paleoclimatologists and Quaternary geologists reported finding what they characterized as well-expressed Younger Dryas events in the Chinese δ18
O records of Termination III[a] in stalagmites from high-altitude caves in Shennongjia area, Hubei Province, China.[27] Various paleoclimatic records from ice cores, deep-sea sediments, speleothems, continental paleobotanical data, and loesses show similar abrupt climate events, which are consistent with Younger Dryas events, during the terminations of the last four glacial periods (see Dansgaard–Oeschger event). They argue that Younger Dryas events might be an intrinsic feature of deglaciations that occur at the end of glacial periods.[27][28][29]
Timing
Analyses of stable isotopes from Greenland ice cores provide estimates for the start and end of the Younger Dryas. The analysis of Greenland Summit ice cores, as part of the Greenland Ice Sheet Project 2 and Greenland Icecore Project, estimated that the Younger Dryas started about 12,800 ice (calibrated) years BP. More recent work with stalagmites strongly suggests a start date of 12,870 ± 30 years BP,[30] consistent with the more recent North Greenland Ice core Project (NGRIP) ice core data.[30] Depending on the specific ice core analysis consulted, the Younger Dryas is estimated to have lasted 1,150–1,300 years.[11][12] Measurements of oxygen isotopes from the GISP2 ice core suggest the ending of the Younger Dryas took place over a period of about 50 years.[31] Other proxy data, such as dust concentration and snow accumulation, suggest an even more rapid transition, lasting for 30 years or less,[32] potentially as rapid as less than 20 years.[31] Greenland experienced about 7 °C (13 °F) of warming in just half a century.[33] Total warming in Greenland was 10 ± 4 °C (18 ± 7 °F).[34]
The end of the Younger Dryas has been dated to around 11,550 years ago, occurring at 10,000 BP (uncalibrated
Years ago Place 11500 ± 50 GRIP ice core, Greenland[35] 11530 + 40
− 60Krakenes Lake, western Norway[36] 11570 Cariaco Basin core, Venezuela[37] 11570 German oak and pine dendrochronology[38] 11640 ± 280 GISP2 ice core, Greenland[39]
The International Commission on Stratigraphy put the start of the Greenlandian stage, and implicitly the end of the Younger Dryas, at 11,700 years before 2000.[40]
Although the start of the Younger Dryas is regarded to be synchronous across the North Atlantic region, recent research concluded that the start of the Younger Dryas might be time-transgressive even within there. After an examination of laminated
According to the analyses of varved sediments from Lake Suigetsu, Japan, and other paleoenvironmental records from Asia, a substantial delay occurred in the onset and the end of the Younger Dryas between Asia and the North Atlantic. For example, paleoenvironmental analysis of sediment cores from Lake Suigetsu in Japan found the Younger Dryas temperature decline of 2–4 °C between 12,300 and 11,250 varve (calibrated) years BP, instead of about 12,900 calibrated years BP in the North Atlantic region.
In contrast, the abrupt shift in the radiocarbon signal from apparent radiocarbon dates of 11,000 radiocarbon years to radiocarbon dates of 10,700–10,600 radiocarbon years BP in terrestrial macrofossils and tree rings in Europe over a 50-year period occurred at the same time in the varved sediments of Lake Suigetsu. However, this same shift in the radiocarbon signal antedates the start of Younger Dryas at Lake Suigetsu by a few hundred years. Interpretations of data from Chinese also confirm that the Younger Dryas East Asia lags the North Atlantic Younger Dryas cooling by at least 200~300 years. Although the interpretation of the data is more murky and ambiguous, the end of the Younger Dryas and the start of Holocene warming likely were similarly delayed in Japan and in other parts of East Asia.[42]
Similarly, an analysis of a stalagmite growing from a cave in Puerto Princesa Subterranean River National Park, Palawan, the Philippines, found that the onset of the Younger Dryas was also delayed there. Proxy data recorded in the stalagmite indicate that more than 550 calibrated years were needed for Younger Dryas drought conditions to reach their full extent in the region and about 450 calibrated years to return to pre-Younger Dryas levels after it ended.[43]
In the Orca Basin in the Gulf of Mexico, a drop in sea surface temperature of approximately 2.4 ± 0.6°C that lasted from 12,800 to 11,600 BP, as measured by Mg/Ca ratios in the planktonic foraminifer Globigerinoides ruber signifies the occurrence of the Younger Dryas in the Gulf of Mexico.[44]
Global effects
The Younger Dryas was globally synchronous or very nearly so.[45] However, the magnitude of the drop in global mean surface temperature was modest; the Younger Dryas was not a global relapse into peak glacial conditions.[46]
In Western Europe and
Effects of the Younger Dryas were of varying intensity throughout North America.
Other features include the following:
- Replacement of forest in Scandinavia with glacial tundra (which is the habitat of the plant Dryas octopetala)
- Glaciationor increased snow in mountain ranges around the world
- Formation of solifluction layers and loess deposits in Northern Europe
- More dust in the atmosphere, originating from deserts in Asia
- A decline in evidence for Natufian hunter gatherer permanent settlements in the Levant, suggesting a reversion to a more mobile way of life[56]
- The Huelmo–Mascardi Cold Reversal in the Southern Hemisphere ended at the same time
- Decline of the Clovis culture; while no definitive cause for the extinction of many species in North America such as the Columbian mammoth, as well as the Dire wolf, Camelops, and other Rancholabrean megafauna during the Younger Dryas has been determined, climate change and human hunting activities have been suggested as contributing factors.[57] Recently, it has been found that these megafauna populations collapsed 1000 years earlier.[58]
North America
Greenland
Despite cold conditions, Greenlandic glaciers retreated during the Younger Dryas,[59] with the exception of some local glaciers in northern Greenland.[60] This was most likely due to a weakening of the Atlantic meridional overturning circulation (AMOC).[59]
East
The Younger Dryas is a period significant to the study of the response of
The effects of the Younger Dryas cooling affected the area that is now New England and parts of maritime Canada more rapidly than the rest of the present day United States at the beginning and the end of the Younger Dryas chronozone.[64][65][66][67] Proxy indicators show that summer temperature conditions in Maine decreased by up to 7.5 °C. Cool summers, combined with cold winters and low precipitation, resulted in a treeless tundra up to the onset of the Holocene, when the boreal forests shifted north.[68]
Vegetation in the central
Central
Also, a gradient of changing effects occurred from the
Rocky Mountains
Effects in the Rocky Mountain region were varied.[78][79] In the northern Rockies, a significant increase in pines and firs suggests warmer conditions than before and a shift to subalpine parkland in places.[80][81][82][83] That is hypothesized to be the result of a northward shift in the jet stream, combined with an increase in summer insolation[80][84] as well as a winter snow pack that was higher than today, with prolonged and wetter spring seasons.[85] There were minor re-advancements of glaciers in place, particularly in the northern ranges,[86][87] but several sites in the Rocky Mountain ranges show little to no changes in vegetation during the Younger Dryas.[81] Evidence also indicates an increase in precipitation in New Mexico because of the same Gulf conditions that were influencing Texas.[88]
West
The Pacific Northwest region experienced 2 to 3 °C of cooling and an increase in precipitation.[89][71][90][91][92][93] Glacial re-advancement has been recorded in British Columbia[94][95] as well as in the Cascade Range.[96] An increase of pine pollen indicates cooler winters within the central Cascades.[97] On the Olympic Peninsula, a mid-elevation site recorded a decrease in fire, but forest persisted and erosion increased during the Younger Dryas, which suggests cool and wet conditions.[98] Speleothem records indicate an increase in precipitation in southern Oregon,[92][99] the timing of which coincides with increased sizes of pluvial lakes in the northern Great Basin.[100] Pollen record from the Siskiyou Mountains suggests a lag in timing of the Younger Dryas, indicating a greater influence of warmer Pacific conditions on that range,[101] but the pollen record is less chronologically constrained than the aforementioned speleothem record. The Southwest appears to have seen an increase in precipitation, as well, also with an average 2 °C of cooling.[102]
Central America
In Costa Rica, rapid swings in temperature at the end of the Younger Dryas closely tracked and matched those observed in Greenland's ice cores, suggesting a common, synchronous cause for these oscillations.[103]
Europe
Since 1916 and the onset and the subsequent refinement of pollen analytical techniques and a steadily-growing number of pollen diagrams, palynologists have concluded that the Younger Dryas was a distinct period of vegetational change in large parts of Europe during which vegetation of a warmer climate was replaced by that of a generally cold climate, a glacial plant succession that often contained Dryas octopetala.[104] The drastic change in vegetation is typically interpreted to be an effect of a sudden decrease in (annual) temperature, unfavorable for the forest vegetation that had been spreading northward rapidly. The cooling not only favored the expansion of cold-tolerant, light-demanding plants and associated steppe fauna, but also led to regional glacial advances in Scandinavia and a lowering of the regional snow line.[11]
The change to glacial conditions at the onset of the Younger Dryas in the higher latitudes of the Northern Hemisphere, between 12,900 and 11,500 calibrated years BP, has been argued to have been quite abrupt.[32] It is in sharp contrast to the warming of the preceding Older Dryas interstadial. Its end has been inferred to have occurred over a period of a decade or so,[31] but the onset may have even been faster.[105] Thermally fractionated nitrogen and argon isotope data from Greenland ice core GISP2 indicate that its summit was around 15 °C (27 °F) colder during the Younger Dryas[32][106] than today.
In Great Britain, the mean annual temperature was no higher than −1 °C (30 °F) as indicated by the presence of permafrost,
In what is now Hesse, the early part of the Younger Dryas saw the development of a multi-channel braidplain. During the later Younger Dryas, this braidplain reverted back to a fluvial system of straight and meandering rivers akin to that which had been the norm during the Allerød oscillation.[109]
In the
Middle East
Anatolia was extremely arid during the Younger Dryas.[112][113] No intensification of geomorphodynamic activity occurred around Gobekli Tepe at the terminus of the Younger Dryas.[114]
East Asia
Pollen records from Lake Gonghai in Shanxi, China show a major increase in aridity synchronous with the onset of the Younger Dryas, believed by some scholars to be a consequence of a weakened East Asian Summer Monsoon (EASM).[115] Some studies, however, have concluded that the EASM instead strengthened during the Younger Dryas.[116]
Africa
Lake Tanganyika experienced a decline in wind-driven seasonal mixing, a phenomenon attributable to the more southerly position of the Intertropical Convergence Zone (ITCZ) and a weakened southwest Indian Monsoon.[117]
Effects on agriculture
The Younger Dryas is often linked to the
Sea level
Based upon solid geological evidence, consisting largely of the analysis of numerous deep cores from coral reefs, variations in the rates of sea level rise have been reconstructed for the postglacial period. For the early part of the sea level rise that is associated with deglaciation, three major periods of accelerated sea level rise, called meltwater pulses, occurred. They are commonly called
- meltwater pulse 1A0 for the pulse between 19,000~19,500 calibrated years ago;
- meltwater pulse 1A for the pulse between 14,600~14,300 calibrated years ago;
- meltwater pulse 1B for the pulse between 11,400~11,100 calibrated years ago.
The Younger Dryas occurred after meltwater pulse 1A, a 13.5 m rise over about 290 years, centered at about 14,200 calibrated years ago, and before meltwater pulse 1B, a 7.5 m rise over about 160 years, centered at about 11,000 calibrated years ago.[122][123][124] Finally, not only did the Younger Dryas postdate both all of meltwater pulse 1A and predate all of meltwater pulse 1B, it was a period of significantly-reduced rate of sea level rise relative to the periods of time immediately before and after it.[122][125]
Possible evidence of short-term sea level changes has been reported for the beginning of the Younger Dryas. First, the plotting of data by Bard and others suggests a small drop, less than 6 m, in sea level near the onset of the Younger Dryas. There is a possible corresponding change in the rate of change of sea level rise seen in the data from both Barbados and Tahiti. Given that this change is "within the overall uncertainty of the approach," it was concluded that a relatively smooth sea-level rise, with no significant accelerations, occurred then.[125] Finally, research by Lohe and others in western Norway has reported a sea-level low-stand at 13,640 calibrated years ago and a subsequent Younger Dryas transgression starting at 13,080 calibrated years ago.[126] They concluded that the timing of the Allerød low-stand and the subsequent transgression were the result of increased regional loading of the crust, and geoid changes were caused by an expanding ice sheet,[127] which started growing and advancing in the early Allerød, about 13,600 calibrated years ago, well before the start of the Younger Dryas.[126]
Ocean circulation
The Younger Dryas resulted in decreased ventilation of ocean bottom waters. Cores from the western subtropical North Atlantic show that the ventilation age of the bottom water there was about 1,000 years, twice the age of Late Holocene bottom waters from the same site around 1,500 BP.[128]
Cause
The Younger Dryas has historically been thought to have been caused by significant reduction or
It is often noted that the Younger Dryas is merely the last of 25 or 26 major climate episodes (
Another idea is that a solar flare may have been responsible for the megafaunal extinction that occurred at approximately the same time as the Younger Dryas, but that cannot explain the apparent variability in the timing of the extinction across all continents.[140][141]
The Younger Dryas impact hypothesis (YDIH) attributes the cooling to the impact of a disintegrating comet or asteroid.[142] Some researchers report detection of impact markers in support of the hypothesis,[142] but others have criticised the detection methods, dating, and interpretation.[143] Examples are a denial of evidence for extensive wildfires prior to the Younger Dryas reported by YDIH proponents, [144] and analysis of Younger Dryas aged sediments from Hall's cave in Texas interpreted by YDIH proponents as extraterrestrial in origin, which are argued to be more likely as volcanic.[9]
An increasingly well-supported alternative to the meltwater trigger is that the Younger Dryas was triggered by volcanism. Numerous papers now confidently link volcanism to a variety of cold events across the last two millennia[145] and the Holocene,[146] and in particular several note the ability of volcanic eruptions to trigger climate change lasting for centuries to millennia.[147][148] It was proposed that a high latitude volcanic eruption could have shifted atmospheric circulation sufficiently to increase North Atlantic sea ice growth and slow down AMOC, subsequently leading to a positive cooling feedback and initiating the Younger Dryas.[7] This perspective is now supported by evidence for volcanism coinciding with the start of the Younger Dryas from both cave deposits[9] and glacial ice cores.[8] Particularly strong support comes from sulphur data from Greenland ice cores showing that the radiative forcing associated with the cluster of eruptions immediately preceding the Younger Dryas initiation "exceeds the most volcanically active periods during the Common Era, which experienced notable multidecadal scale cooling commonly attributed to volcanic effects[8]". Notably, the sulphur data strongly suggest that a very large and high latitude northern hemisphere eruption occurred 12,870 years ago,[8] a date indistinguishable from the stalagmite-derived onset of the Younger Dryas event.[30] It is unclear which eruption was responsible for this sulphur spike, but the characteristics are consistent with the Laacher See eruption as the source. The eruption was dated to 12,880 ± 40 years BP by varve counting sediment in a German lake[149] and to 12,900 ± 560 years by 40Ar/39Ar dating,[150] both of which are within dating uncertainites of the sulphur spike at 12,870 years BP, and make the Laacher See eruption a possible trigger for the Younger Dryas. However, a new radiocarbon date challenges the previous dating for the Laacher See eruption, moving it back to 13,006 years BP,[151] but this date itself has been challenged as potentially having been affected by radiocarbon 'dead' magmatic carbon dioxide, which was not accounted for and made the date appear older than it was.[152] Regardless of the ambiguity surrounding the date for the Laacher See eruption, it almost certainly caused substantial cooling either immediately before the Younger Dryas event[7][152] or as one of the several eruptions which clustered in the ~100 years preceding the event.[8]
A volcanic trigger for the Younger Dryas event also explains why there was little sea level change at the beginning of the event.[137] Furthermore, it is also consistent with previous work that links volcanism with D-O events[153][154] and with the perspective that the Younger Dryas is simply the most recent D-O event.[155] It is worth noting that of the proposed Younger Dryas triggers, the volcanic trigger is the only one with evidence that is almost universally accepted as reflecting the actual occurrence of the trigger. No consensus exists that a meltwater pulse happened, or that a bolide impact occurred prior to the Younger Dryas, whereas the evidence of anomalously strong volcanism prior to the Younger Dryas event is now very strong.[7][8][9][152] Outstanding questions include whether a short-lived volcanic forcing can trigger 1,300 years of cooling, and how background climate conditions affect the climate response to volcanism.
End of the Younger Dryas
The end of the Younger Dryas was likely caused by among other theories, an increase in carbon dioxide levels, as well as a shift in
In popular culture
In the 2004 film, the
See also
- 8.2 kiloyear climate event – Rapid global cooling around 8,200 years ago
- Preboreal oscillation - Cooling episode within the preboreal
- Heinrich event – Large groups of icebergs traverse the North Atlantic.
- Little Ice Age – Climatic cooling after the Medieval Warm Period (16th–19th centuries)
- Medieval Warm Period – Time of warm climate in the North Atlantic region lasting from c. 950 to c. 1250
- Neoglaciation
- Timeline of glaciation – Chronology of the major ice ages of the Earth
- Timeline of environmental history
- Beaufort Gyre reversal
- Milankovitch cycles
Footnotes
- ^ a b c The relatively rapid changes from cold conditions to warm interglacials are called terminations). They are numbered from the most recent termination as I and with increasing value (II, III, and so forth) into the past. Termination I is the end Marine Isotope Stage 2 (Last Glacial Maximum); Termination II is the end of the Marine Isotope Stage 6 (c. 130,000 years BP); Termination III is the end of Marine Isotope Stage 8 (c. 243,000 years BP); Termination IV is the end of Marine Isotope Stage 10 (337,000 years BP).[23][24]
References
- ^ Zalloua & Matisoo-Smith 2017.
- ^ Rasmussen et al. 2006.
- ^ Clement & Peterson 2008.
- S2CID 206558186. Retrieved 18 September 2023.
- .
- ^ ISSN 0277-3791.
- ^ ISSN 1814-9324.
- ^ .
- ^ PMID 32789166.
- ^ Carlson, A.E. (2013). "The Younger Dryas Climate Event" (PDF). Encyclopedia of Quaternary Science. Vol. 3. Elsevier. pp. 126–134. Archived from the original (PDF) on 11 March 2020.
- ^ a b c Björck, S. (2007) Younger Dryas oscillation, global evidence. In S. A. Elias, (Ed.): Encyclopedia of Quaternary Science, Volume 3, pp. 1987–1994. Elsevier B.V., Oxford.
- ^ S2CID 45121979.
- ^ Andersson, Gunnar (1896). Svenska växtvärldens historia [Swedish history of the plant world] (in Swedish). Stockholm: P.A. Norstedt & Söner.
- ^ Hartz, N.; Milthers, V. (1901). "Det senglacie ler i Allerød tegelværksgrav" [The late glacial clay of the clay-pit at Alleröd]. Meddelelser Dansk Geologisk Foreningen (Bulletin of the Geological Society of Denmark) (in Danish). 2 (8): 31–60.
- .
- ISBN 978-0-415-67455-3.
- S2CID 128688449.
- S2CID 129434790.
- .
- .
- doi:10.7202/008301ar.
- S2CID 12788441.
- U. Hawaii.
- S2CID 12788441.
- ^ ISBN 978-0-12-386913-5.
- ^ Eglinton, G., A.B. Stuart, A. Rosell, M. Sarnthein, U. Pflaumann, and R. Tiedeman (1992) Molecular record of secular sea surface temperature changes on 100-year timescales for glacial terminations I, II and IV. Nature. 356:423–426.
- ^ S2CID 129007340.
- .
- ^ Xiaodong, D.; Liwei, Z.; Shuji, K. (2014). "A review on the Younger Dryas event". Advances in Earth Science. 29 (10): 1095–1109.
- ^ PMID 32900942.
- ^ S2CID 4325976. Retrieved 18 September 2023.
- ^ .
- S2CID 4239314.
- .
- .
- .
- S2CID 129916026.
- PMID 11110659.
- ^ S2CID 4342230.
- S2CID 40380068. Retrieved 11 November 2019.
- .
- S2CID 350762.
- ^ Partin, J.W., T.M. Quinn, C.-C. Shen, Y. Okumura, M.B. Cardenas, F.P. Siringan, J.L. Banner, K. Lin, H.-M. Hu, and F.W Taylor (2014) Gradual onset and recovery of the Younger Dryas abrupt climate event in the tropics. Nature Communications. Received 10 October 2014 | Accepted 13 July 2015 | Published 2 September 2015
- S2CID 58890724. Retrieved 13 April 2023.
- ISSN 1476-4687. Retrieved 29 September 2023.
- ISSN 0277-3791. Retrieved 30 September 2023.
- ^ "Climate Change 2001: The Scientific Basis". Grida.no. Archived from the original on 24 September 2015. Retrieved 24 November 2015.
- ^ "New clue to how last ice age ended". ScienceDaily. Archived from the original on 11 September 2010.
- .
- ISSN 0267-8179. Retrieved 19 December 2023 – via Wiley Online Library.
- S2CID 38790253. Retrieved 19 December 2023.
- OCLC 846470730.
- .
- .
- S2CID 1633393.
- ISBN 978-1-4729-2294-6.
- ^ Brakenridge, G. Robert. 2011. Core-Collapse Supernovae and the Younger Dryas/Terminal Rancholabrean Extinctions. Elsevier, Retrieved 23 September 2018
- S2CID 206522597.
- ^ PMID 30093676.
- ISSN 0277-3791. Retrieved 18 September 2023.
- S2CID 129095089.
- ^ S2CID 3086333.
- S2CID 228885304.
- .
- .
- doi:10.1130/g30781.1.
- S2CID 130800017.
- S2CID 87182583.
- ^ S2CID 55704048.
- ^ S2CID 133557318.
- ^ OCLC 846470730.
- .
- PMID 9856941.
- ^ OCLC 276334680.
- S2CID 129027867.
- ISSN 0008-4077.
- ISSN 1939-9170.
- OCLC 907959421.
- S2CID 55554570.
- ^ .
- ^ S2CID 129531002.
- ^ "Precise cosmogenic 10Be measurements in western North America: Support for a global Younger Dryas cooling event". ResearchGate. Retrieved 12 June 2017.
- ISSN 0091-7613.
- ISSN 0091-7613.
- S2CID 9377272.
- .
- .
- .
- ISSN 1944-9186.
- ISSN 1944-8007.
- .
- ^ S2CID 1633393.
- .
- .
- S2CID 129896627.
- .
- S2CID 129306849.
- ISSN 0012-9615.
- S2CID 5850258.
- S2CID 129249661.
- S2CID 17330671.
- S2CID 55309102.
- S2CID 4344716. Retrieved 25 December 2023.
- ISSN 0300-9483.
- ^ Choi, Charles Q. (2 December 2009). "Big freeze: Earth could plunge into sudden ice age". Live Science. Retrieved 2 December 2009.
- ^ S2CID 4426618.
- S2CID 4306228.
- S2CID 129774709. Retrieved 21 September 2023.
- ISSN 0277-3791. Retrieved 22 November 2023.
- ISSN 2661-863X. Retrieved 18 September 2023.
- ISSN 0169-555X. Retrieved 21 September 2023.
- ISSN 0277-3791. Retrieved 21 September 2023.
- ISSN 0094-8276. Retrieved 21 September 2023.
- ISSN 0197-9337. Retrieved 21 September 2023.
- S2CID 134259679.
- . Retrieved 16 April 2023.
- S2CID 129722161. Retrieved 25 December 2023.
- ISBN 978-398042415-8.
- ^ Mithen, Steven J. (2003). After the Ice: A global human history, 20,000–5000 BC (paperback ed.). Harvard University Press. pp. 46–55.
- ^ Munro, N.D. (2003). "Small game, the younger dryas, and the transition to agriculture in the southern levant" (PDF). Mitteilungen der Gesellschaft für Urgeschichte. 12: 47–64. Archived from the original (PDF) on 2 June 2020. Retrieved 8 December 2005.
- PMID 20093449.
- ^ ISBN 978-90-481-2638-5.
- ISBN 978-90-481-2638-5.
- .
- ^ S2CID 29689776.
- ^ hdl:1956/1179.
- S2CID 53140679. Retrieved 18 September 2023.
- S2CID 129340391.
- ^ S2CID 39544213.
- S2CID 133852610.
- S2CID 4425933.
- ISSN 2662-4435. Retrieved 21 September 2023.
- PMID 26573386.
- ISSN 0091-7613.
- S2CID 6896108.
- ^ ISSN 2169-897X.
- ^ ISSN 0883-8305.
- S2CID 35224174.
- PMID 27814029.
- . Retrieved 20 April 2012.
- ^ Staff Writers (6 June 2011). "Did a massive Solar proton event fry the Earth?". Space Daily. Archived from the original on 23 December 2018. Retrieved 24 June 2021.
- ^ PMID 34986034.
- .
- ^ Gramling C (26 June 2018). "Why won't this debate about an ancient cold snap die?". Science News. Archived from the original on 5 August 2021. Retrieved 23 February 2023.
- S2CID 4462058.
- PMID 28469185.
- PMID 28469185.
- .
- .
- .
- S2CID 235696831.
- ^ S2CID 259336241.
- PMID 26616338.
- ISSN 1814-9332.
- ISSN 1814-9332.
- S2CID 2152480. Retrieved 17 January 2023.
- ^ Lovgren, Stefan (18 May 2004). "Day After Tomorrow Movie: Could Ice Age Occur Overnight?". National Geographic News. Archived from the original on 20 May 2004. Retrieved 24 June 2023.
Cited sources
- Zalloua, Pierre A.; Matisoo-Smith, Elizabeth (2017). "Mapping Post-Glacial expansions: The Peopling of Southwest Asia". PMID 28059138.
- Rasmussen, S. O.; Andersen, K. K.; Svensson, A. M.; Steffensen, J. P.; Vinther, B. M.; Clausen, H. B.; Siggaard-Andersen, M.-L.; Johnsen, S. J.; Larsen, L. B.; Dahl-Jensen, D.; Bigler, M. (2006). "A new Greenland ice core chronology for the last glacial termination" (PDF). Journal of Geophysical Research. 111 (D6). ISSN 0148-0227.
- Clement, Amy C.; Peterson, Larry C. (2008). "Mechanisms of abrupt climate change of the last glacial period". S2CID 7828663. Retrieved 20 January 2023.
External links
- "Study confirms mechanism for current shutdowns, European cooling" (Press release). Oregon State University. 2007. Archived from the original on 17 December 2010. Retrieved 11 April 2011.
- Broecker, W.S. (1999). "What If the Conveyor Were to Shut Down?". GSA Today. 9 (1): 1–7. Retrieved 11 April 2011.
- Calvin, W.H. (January 1998). "The great climate flip-flop". The Atlantic Monthly. Vol. 281. pp. 47–64. Retrieved 11 April 2011.
- Tarasov, L.; Peltier, W.R. (June 2005). "Arctic freshwater forcing of the Younger Dryas cold reversal" (PDF). Nature. 435 (7042): 662–665. S2CID 4375841. Archived from the original(PDF) on 21 August 2015.
- Acosta; et al. (2018). "Climate change and peopling of the Neotropics during the Pleistocene-Holocene transition". Boletín de la Sociedad Geológica Mexicana. 70: 1–19. .
- "Cometary debris may have destroyed Paleolithic settlement 12,800 years ago". Science News (sci-news.com) (Press release). 2 July 2020.
- When the Earth suddenly stopped warming. .