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

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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Bipolar volcanic synchronization of abrupt climate change in Greenland and Antarctic ice cores during the last glacial period

Climate of the Past ◽

10.5194/cp-16-1565-2020 ◽

2020 ◽

Vol 16 (4) ◽

pp. 1565-1580

Author(s):

Anders Svensson ◽

Dorthe Dahl-Jensen ◽

Jørgen Peder Steffensen ◽

Thomas Blunier ◽

Sune O. Rasmussen ◽

...

Keyword(s):

Ice Core ◽

Ice Cores ◽

Volcanic Eruptions ◽

Abrupt Climate Change ◽

Glacial Period ◽

Deuterium Excess ◽

Last Glacial Period ◽

Last Glacial ◽

The Antarctic ◽

The Last Glacial

Abstract. The last glacial period is characterized by a number of millennial climate events that have been identified in both Greenland and Antarctic ice cores and that are abrupt in Greenland climate records. The mechanisms governing this climate variability remain a puzzle that requires a precise synchronization of ice cores from the two hemispheres to be resolved. Previously, Greenland and Antarctic ice cores have been synchronized primarily via their common records of gas concentrations or isotopes from the trapped air and via cosmogenic isotopes measured on the ice. In this work, we apply ice core volcanic proxies and annual layer counting to identify large volcanic eruptions that have left a signature in both Greenland and Antarctica. Generally, no tephra is associated with those eruptions in the ice cores, so the source of the eruptions cannot be identified. Instead, we identify and match sequences of volcanic eruptions with bipolar distribution of sulfate, i.e. unique patterns of volcanic events separated by the same number of years at the two poles. Using this approach, we pinpoint 82 large bipolar volcanic eruptions throughout the second half of the last glacial period (12–60 ka). This improved ice core synchronization is applied to determine the bipolar phasing of abrupt climate change events at decadal-scale precision. In response to Greenland abrupt climatic transitions, we find a response in the Antarctic water isotope signals (δ18O and deuterium excess) that is both more immediate and more abrupt than that found with previous gas-based interpolar synchronizations, providing additional support for our volcanic framework. On average, the Antarctic bipolar seesaw climate response lags the midpoint of Greenland abrupt δ18O transitions by 122±24 years. The time difference between Antarctic signals in deuterium excess and δ18O, which likewise informs the time needed to propagate the signal as described by the theory of the bipolar seesaw but is less sensitive to synchronization errors, suggests an Antarctic δ18O lag behind Greenland of 152±37 years. These estimates are shorter than the 200 years suggested by earlier gas-based synchronizations. As before, we find variations in the timing and duration between the response at different sites and for different events suggesting an interaction of oceanic and atmospheric teleconnection patterns as well as internal climate variability.

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Bipolar volcanic synchronization of abrupt climate change in Greenland and Antarctic ice cores during the last glacial period

10.5194/cp-2020-41 ◽

2020 ◽

Cited By ~ 1

Author(s):

Anders Svensson ◽

Dorthe Dahl-Jensen ◽

Jørgen Peder Steffensen ◽

Thomas Blunier ◽

Sune O. Rasmussen ◽

...

Keyword(s):

Climate Change ◽

Ice Core ◽

Ice Cores ◽

Volcanic Eruptions ◽

Abrupt Climate Change ◽

Glacial Period ◽

Deuterium Excess ◽

Last Glacial Period ◽

Last Glacial ◽

The Last Glacial

Abstract. The last glacial period is characterized by a number of abrupt climate events that have been identified in both Greenland and Antarctic ice cores. The mechanisms governing this climate variability remain a puzzle that requires a precise synchronization of ice cores from the two Hemispheres to be resolved. Previously, Greenland and Antarctic ice cores have been synchronized primarily via their common records of gas concentrations or isotopes from the trapped air and via cosmogenic isotopes measured on the ice. In this work, we apply ice-core volcanic proxies and annual layer counting to identify large volcanic eruptions that have left a signature in both Greenland and Antarctica. Generally, no tephra is associated with those eruptions in the ice cores, so the source of the eruptions cannot be identified. Instead, we identify and match sequences of volcanic eruptions with bipolar distribution of sulfate, i.e. unique patterns of volcanic events separated by the same number of years at the two poles. Using this approach, we pinpoint 80 large bipolar volcanic eruptions throughout the second half of the last glacial period (12–60 ka before present). This improved ice-core synchronization is applied to determine the bipolar phasing of abrupt climate change events at decadal-scale precision. During abrupt transitions, we find more coherent Antarctic water isotopic signals (δ18O and deuterium excess) than was obtained from previous gas-based synchronizations, providing additional support for our volcanic framework. On average, the Antarctic bipolar seesaw climate response lags the midpoint of Greenland abrupt δ18O transitions by 122 ± 24 years. The time difference between Antarctic signals in deuterium excess and δ18O, which is less sensitive to synchronization errors, suggests an Antarctic δ18O lag of 152 ± 37 years. These estimates are shorter than the 200 years suggested by earlier gas-based synchronizations. As before, we find variations in the timing and duration between the response at different sites and for different events suggesting an interaction of oceanic and atmospheric teleconnection patterns as well as internal climate variability.

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Volcanic forcing and climate variations during the last glacial period

Climate of the Past Discussions ◽

10.5194/cpd-8-4941-2012 ◽

2012 ◽

Vol 8 (5) ◽

pp. 4941-4956

Author(s):

A. F. Flinders

Keyword(s):

Late Quaternary ◽

Ice Core ◽

Greenland Ice Sheet ◽

Volcanic Eruptions ◽

Temporal Variations ◽

Atmospheric Co2 ◽

Glacial Period ◽

Last Glacial Period ◽

Last Glacial ◽

The Last Glacial

Abstract. Measurements of δ18O in the Greenland Ice Sheet Project 2 (GISP2) ice-core from Summit, Greenland, show repeated temporal variations associated with rapid warming events throughout the last glacial period of the Pleistocene-10–110 kya. The majority of these warming events are preceded in the ice-core record by an increased concentration of insoluble micro-particulate sulfate, indicative of increases in global volcanism. Wavelet analysis of ice-core and marine-sediment records show a repeated 5000–6000 yr periodicity in both volcanic SO4 and δ18O ice records, as well as a 5000–8000 yr cycle in the lithic concentration of ice-rafted debris, atmospheric CO2 concentration, and a database of late Quaternary volcanic eruptions. Increasing concentrations in atmospheric CO2 and CH4 initiated during periods of increased volcanism, peaking during a warm transition, reflect a volcanic-atmospheric-deglaciation feedback, regulated by meridional overturning current-shutdown related cooling.

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