Understanding drivers of glacier-length variability  over the last millennium

Huston, Alan; Siler, Nicholas; Roe, Gerard H.; Pettit, E. C.; Steiger, Nathan J.

doi:10.5194/tc-15-1645-2021

Cited by 12 publications

(6 citation statements)

References 39 publications

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“…Glaciers respond to climate fluctuations sensitively and are important elements for understanding the climate of the past (Huston et al, 2021;Roe et al, 2017). Reconstructing former ice margins allows for deciphering glacier fluctuations across time and space and informs us of climate variations that drove these changes.…”

Section: Introductionmentioning

confidence: 99%

Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps

et al. 2021

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Abstract. Glaciers preserve climate variations in their geological and geomorphological records, which makes them prime candidates for climate reconstructions. Investigating the glacier–climate system over the past millennia is particularly relevant first because the amplitude and frequency of natural climate variability during the Holocene provides the climatic context against which modern, human-induced climate change must be assessed. Second, the transition from the last glacial to the current interglacial promises important insights into the climate system during warming, which is of particular interest with respect to ongoing climate change. Evidence of stable ice margin positions that record cooling during the past 12 kyr are preserved in two glaciated valleys of the Silvretta Massif in the eastern European Alps, the Jamtal (JAM) and the Laraintal (LAR). We mapped and dated moraines in these catchments including historical ridges using beryllium-10 surface exposure dating (10Be SED) techniques and correlate resulting moraine formation intervals with climate proxy records to evaluate the spatial and temporal scale of these cold phases. The new geochronologies indicate the formation of moraines during the early Holocene (EH), ca. 11.0 ± 0.7 ka (n = 19). Boulder ages along historical moraines (n = 6) suggest at least two glacier advances during the Little Ice Age (LIA; ca. 1250–1850 CE) around 1300 CE and in the second half of the 18th century. An earlier advance to the same position may have occurred around 500 CE. The Jamtal and Laraintal moraine chronologies provide evidence that millennial-scale EH warming was superimposed by centennial-scale cooling. The timing of EH moraine formation coincides with brief temperature drops identified in local and regional paleoproxy records, most prominently with the Preboreal Oscillation (PBO) and is consistent with moraine deposition in other catchments in the European Alps and in the Arctic region. This consistency points to cooling beyond the local scale and therefore a regional or even hemispheric climate driver. Freshwater input sourced from the Laurentide Ice Sheet (LIS), which changed circulation patterns in the North Atlantic, is a plausible explanation for EH cooling and moraine formation in the Nordic region and in Europe.

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Section: Introductionmentioning

confidence: 99%

Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps

et al. 2021

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“…Mountain glaciers are highly sensitive to climate variations, most importantly to changes in summer temperatures and to a lesser extent to changes in precipitation 1 , 2 . This sensitivity is evident in the accelerating deglaciation of alpine regions caused by rapid warming due to increasing greenhouse gas emissions in recent decades 3 .…”

Section: Introductionmentioning

confidence: 99%

Moraines in the Austrian Alps record repeated phases of glacier stabilization through the Late Glacial and the Early Holocene

Braumann

Schaefer

Neuhuber

et al. 2022

Sci Rep

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Climate is currently warming due to anthropogenic impact on the Earth’s atmosphere. To better understand the processes and feedbacks within the climate system that underlie this accelerating warming trend, it is useful to examine past periods of abrupt climate change that were driven by natural forcings. Glaciers provide an excellent natural laboratory for reconstructing the climate of the past as they respond sensitively to climate oscillations. Therefore, we study glacier systems and their behavior during the transition from colder to warmer climate phases, focusing on the period between 15 and 10 ka. Using a combination of geomorphological mapping and beryllium-10 surface exposure dating, we reconstruct ice extents in two glaciated valleys of the Silvretta Massif in the Austrian Alps. The mountain glacier record shows that general deglaciation after the Last Glacial Maximum (LGM) was repeatedly interrupted by glacier stabilization or readvance, perhaps during the Oldest Dryas to Bølling transition (landform age: 14.4 ± 1.0 ka) and certainly during the Younger Dryas (YD; 12.9–11.7 ka) and the Early Holocene (EH; 12–10 ka). The oldest landform age indicates a lateral ice margin that postdates the ‘Gschnitz’ stadial (ca. 17–16 ka) and predates the YD. It shows that local inner-alpine glaciers were more extensive until the onset of the Bølling warm phase (ca. 14.6 ka), or possibly even into the Bølling than during the subsequent YD. The second age group, ca. 80 m below the (pre-)Bølling ice margin, indicates glacier extents during the YD cold phase and captures the spatial and temporal fine structure of glacier retreat during this period. The ice surface lowered approximately 50–60 m through the YD, which is indicative of milder climate conditions at the end of the YD compared to its beginning. Finally, the third age group falls into a period of more substantial warming, the YD–EH transition, and shows discontinuous glacier retreat during the glacial to interglacial transition. The new geochronologies synthesized with pre-existing moraine records from the Silvretta Massif evidence multiple cold phases that punctuated the general post-LGM warming trend and illustrate the sensitive response of Silvretta glaciers to abrupt climate oscillations in the past.

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“…Mountain glaciers are highly sensitive to climate variations, most importantly to changes in summer temperatures and to a lesser extent to changes in precipitation 1,2 . This sensitivity is evident in the accelerating deglaciation of alpine regions caused by rapid warming due to increasing greenhouse gas emissions in recent decades 3, chapter 3, section 3.3 .…”

Section: Introductionmentioning

confidence: 99%

Moraines in the Austrian Alps Record Repeated Phases of Glacier Stabilization through the Late Glacial and the Early Holocene

Braumann

Schaefer

Neuhuber

et al. 2022

Preprint

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Climate is currently warming due to anthropogenic impact on the Earth’s atmosphere. To better understand the processes and feedbacks within the climate system that underlie this accelerating warming trend, it is useful to examine past periods of abrupt climate change that were driven by natural forcings. Glaciers provide an excellent natural laboratory for reconstructing the climate of the past as they respond sensitively to climate oscillations. Therefore, we study glacier systems and their behavior during the transition from colder to warmer climate episodes, focusing on the period between 15 and 10 ka. Using a combination of geomorphological mapping and beryllium-10 surface exposure dating, we reconstruct ice extents in two glaciated valleys of the Silvretta Massif in the Austrian Alps and find that the general ice retreat during the deglaciation after the Last Glacial Maximum (LGM) was interrupted by glacier stabilization during the Oldest Dryas to Bølling transition (moraine age: 14.4 ± 1.0 ka), during the Younger Dryas (YD; 12.9-11.7 ka), and during the Early Holocene (EH; 12–10 ka). The first moraine age group indicates a lateral stable ice margin that postdates the ‘Gschnitz’ stadial (ca. 17–16 ka) and predates the YD. It shows that local inner-alpine glaciers were larger than during the subsequent YD until the onset of the Bølling warm phase (ca. 14.6 ka), or possibly even into the Bølling. The second age group ca. 80 m below the (pre-)Bølling moraine indicates ice extents during the YD cold phase and captures the spatial and temporal fine structure of glacier retreat during this period. The ice surface lowered by 50–60 m through the YD, which is indicative of milder climate conditions at the end of the YD compared to its beginning. Finally, the third age group falls into a period of more substantial warming, the YD–EH transition, and shows discontinuous warming during the glacial to interglacial transition. The new geochronologies synthesized with pre-existing moraine records from the Silvretta Massif evidence three cold phases that punctuated the general post-LGM warming trend, and illustrate the sensitive response of Silvretta glaciers to abrupt climate oscillations in the past.

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Understanding drivers of glacier-length variability over the last millennium

Cited by 12 publications

References 39 publications

Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps

Early Holocene cold snaps and their expression in the moraine record of the eastern European Alps

Moraines in the Austrian Alps record repeated phases of glacier stabilization through the Late Glacial and the Early Holocene

Moraines in the Austrian Alps Record Repeated Phases of Glacier Stabilization through the Late Glacial and the Early Holocene

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