Climate Events and Cycles During the Last Glacial-Interglacial Transition

Abstract. During the last glacial period, several large abrupt climate fluctuations took place on the Greenland ice cap and elsewhere. Often these Dansgaard/Oeschger events are assumed to have been synchronous, and then used as tie-points to link chronologies between the proxy archives. However, if temporally separate events are lumped into one illusionary event, climatic interpretations of the tuned events will obviously be flawed. Here, we compare Dansgaard/Oeschger-type events in a well-dated record from south-eastern France with those in Greenland ice cores. Instead of assuming simultaneous climate events between both archives, we keep their age models independent. Even these well-dated archives possess large chronological uncertainties, that prevent us from inferring synchronous climate events at decadal to multi-centennial time scales. If possible, tuning of proxy archives should be avoided.

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Glacial events during the last glacial termination in the Pagele valley, Qiongmu Gangri peak, southern Tibetan Plateau, and their links to oceanic and atmospheric circulation

Quaternary Research ◽

10.1017/qua.2020.7 ◽

2020 ◽

Vol 95 ◽

pp. 129-141

Author(s):

Xiangke Xu ◽

Tandong Yao ◽

Baiqing Xu ◽

Chaolu Yi ◽

Yong Sun ◽

...

Keyword(s):

Tibetan Plateau ◽

Atmospheric Circulation ◽

The Tibetan Plateau ◽

Positive Role ◽

Climate Trend ◽

Last Glacial ◽

Exposure Dating ◽

Climate Events ◽

The Last Glacial ◽

Glacial Termination

AbstractDuring the last glacial termination, a warming trend was generally interrupted by rapid millennium-scale cold reversals, such as the Greenland (Isotope) Stadial 1 (GS-1) and GS-2a events. To understand how glaciers on the Tibetan Plateau (TP) responded to these rapid climate events, this study constrained the timing and extent of three glacial events during the late-glacial period. Specifically, using a cosmogenic 10Be exposure dating method, we dated three prominent glacial moraines (PM1, PM2, PM3) back to 15,850 ± 980, 14,140 ± 880, and 12,430 ± 790 yr in the Pagele valley, southern TP, corresponding to GS-2a, Greenland Interstadial 1 (GI-1), and GS-1, respectively. By simulating glacial extents forced by different climate scenarios, the study constrained the temperature decreases relative to present to be 2.6°C–2.9°C, ~1.6°C, and 1.4°C–1.5°C during the GS-2a, GI-1, and GS-1 periods in the region, with precipitation values of 60%–80%, ~100%, and 80%–90% of present value, respectively. Considering information from oceanic and atmospheric circulation, the study suggested that on the TP, the glacial events during the last glacial termination were well connected with the millennium-scale climate events in the North Atlantic region through the westerlies, while the Indian summer monsoon played a positive role in sustaining the glaciers under the warming climate trend.

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Supplementary material to "Regional seesaw between North Atlantic and Nordic Seas during the last glacial abrupt climate events"

10.5194/cp-2017-14-supplement ◽

2017 ◽

Author(s):

Mélanie Wary ◽

Frédérique Eynaud ◽

Didier Swingedouw ◽

Valérie Masson-Delmotte ◽

Jens Matthiessen ◽

...

Keyword(s):

North Atlantic ◽

Nordic Seas ◽

Last Glacial ◽

Supplementary Material ◽

Climate Events ◽

The Last Glacial

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The role of volcanism for abrupt climate change during the last glacial period

10.5194/egusphere-egu2020-12846 ◽

2020 ◽

Author(s):

Anders Svensson ◽

Johannes Lohmann ◽

Sune Olander Rasmussen ◽

Christo Buizert

Keyword(s):

North Atlantic ◽

Ice Core ◽

Volcanic Eruptions ◽

Abrupt Climate Change ◽

Glacial Period ◽

Last Glacial Period ◽

Last Glacial ◽

Heinrich Events ◽

Climate Events ◽

The Last Glacial

During the last glacial period, abrupt climate events known as Dansgaard-Oeschger (DO) and Heinrich events have been observed in various types of Northern Hemispheric (NH) paleoclimate archives. It has been speculated that volcanism may play a role in the abrupt climate variability of the last glacial period, for example as a trigger of abrupt changes. The investigation of a possible link between abrupt climate events and volcanic eruptions has been hampered by the lack of a global volcanic eruption record from the last glacial period. A recent identification of 80 major bipolar volcanic eruptions in Greenland and Antarctic ice core records within the interval 12-60 ka BP now enables us to investigate this link.Using high-resolution ice-core records of climate (&#948;18O), atmospheric circulation changes (calcium) and volcanic eruptions (sulfate and other volcanic proxies) we investigate the timing of abrupt climate events and large volcanic eruptions at decadal resolution. We consider possible links between major volcanic eruptions and DO onsets (NH warming), DO terminations (NH cooling), and Heinrich stadials (strong NH cooling). Heinrich stadials are cold Greenland stadial periods during which Heinrich events occurred; large Hudson Strait iceberg discharge events that are characterized by deposition of significant amounts of ice rafted debris in North Atlantic marine sediments.Significant links of volcanic and climatic events are tested in a statistical framework under the null hypothesis of random and memoryless volcanic activity. Our analysis shows that while certainly not all abrupt climate change of the last glacial period is associated with volcanism, we find that volcanism may have induced some abrupt Greenland warming events and perhaps several of the extreme North Atlantic cold Heinrich stadials; no significant link is found between volcanism and DO terminations. We speculate that volcanic cooling can drive such transitions when the coupled system of Atlantic Ocean circulation and North Atlantic sea ice is close to a tipping point.

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