Proxy benchmarks for intercomparison of 8.2 ka simulations

Morrill, C.; Anderson, David M.; Bauer, B. A.; Buckner, Randy L.; Gille, E. P.; Gross, Wendy S.; Hartman, Michael; Shah, A.

doi:10.5194/cpd-8-3765-2012

Cited by 10 publications

(10 citation statements)

References 48 publications

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“…Records of the 8.2 ka event at lower latitudes help to delineate the response of near-modern climate to this perturbation. Although documenting the spatial extent and duration of the 8.2 ka event from proxy records outside of Greenland has been challenging due to the brevity of the event 6 , mounting evidence from mid-latitude and tropical records suggests cooling in the North Atlantic region 7 , and a southward shift of the Intertropical Convergence Zone (ITCZ) and associated precipitation bands 8 . In British Columbia, lake sediments suggest glacial advance, consistent with a cooler and/or wetter climate 9 , and marine sediments indicate decreased sea surface temperatures along the northern California coast 10 .…”

Section: Introductionmentioning

confidence: 99%

Climate response to the 8.2 ka event in coastal California

Oster

Sharp

Covey

et al. 2017

Sci Rep

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A fast-growing stalagmite from the central California coast provides a high-resolution record of climatic changes synchronous with global perturbations resulting from the catastrophic drainage of proglacial Lake Agassiz at ca. 8.2 ka. High frequency, large amplitude variations in carbon isotopes during the 8.2 ka event, coupled with pulsed increases in phosphorus concentrations, indicate more frequent or intense winter storms on the California coast. Decreased magnesium-calcium ratios point toward a sustained increase in effective moisture during the event, however the magnitude of change in Mg/Ca suggests this event was not as pronounced on the western North American coast as anomalies seen in the high northern latitudes and monsoon-influenced areas. Nevertheless, shifts in the White Moon Cave record that are synchronous within age uncertainties with cooling of Greenland, and changes in global monsoon systems, suggest rapid changes in atmospheric circulation occurred in response to freshwater input and associated cooling in the North Atlantic region. Our record is consistent with intensification of the Pacific winter storm track in response to North Atlantic freshwater forcing, a mechanism suggested by simulations of the last deglaciation, and indicates this intensification led to increases in precipitation and infiltration along the California coast during the Holocene.

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Section: Introductionmentioning

confidence: 99%

Climate response to the 8.2 ka event in coastal California

Oster

Sharp

Covey

et al. 2017

Sci Rep

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“…S1 -stars). Mean anomalies of oxygen isotope ratios in seawater (δ 18 O sw ), carbonate (δ 18 O c ), ice (δ 18 O ice ), and SSTs, were taken from Morrill et al 47 . These proxy anomalies are based on data from 27 cores (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Overall, our analysis includes ten SST records, ten δ 18 O sw records, seven δ 18 O c records and eight δ 18 O ice records. The mean anomalies in the simulations are calculated following the methodology by Morrill et al 47 . They are defined as the difference between SST (or δ 18 O) values averaged between 7.9 and 8.5 ka and their climatological mean, only for values above (or below) the mean plus (minus) two standard deviations.…”

Section: Methodsmentioning

confidence: 99%

Magnitude of the 8.2 ka event freshwater forcing based on stable isotope modelling and comparison to future Greenland melting

Aguiar

Meißner

Montenegro

et al. 2021

Sci Rep

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The northern hemisphere experienced an abrupt cold event ~ 8200 years ago (the 8.2 ka event) that was triggered by the release of meltwater into the Labrador Sea, and resulting in a weakening of the poleward oceanic heat transport. Although this event has been considered a possible analogue for future ocean circulation changes due to the projected Greenland Ice Sheet (GIS) melting, large uncertainties in the amount and rate of freshwater released during the 8.2 ka event make such a comparison difficult. In this study, we compare sea surface temperatures and oxygen isotope ratios from 28 isotope-enabled model simulations with 35 paleoproxy records to constrain the meltwater released during the 8.2 ka event. Our results suggest that a combination of 5.3 m of meltwater in sea level rise equivalent (SLR) released over a thousand years, with a short intensification over ~ 130 years (an additional 2.2 m of equivalent SLR) due to routing of the Canadian river discharge, best reproduces the proxy anomalies. Our estimate is of the same order of magnitude as projected future GIS melting rates under the high emission scenario RCP8.5.

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“…The 8.2‐ka BP climate event provides an ideal test case for a first comparison between hydrogen and oxygen records from a mid‐latitude Sphagnum moss archive given that it was the most severe climatic event in the Holocene and appears to have had most pronounced impact in the northern mid‐ to high latitudes (Alley and Ágústsdóttir, ; Rohling and Pälike, ; Thomas et al ., ; Daley et al ., ; Morrill et al ., ). The 8.2‐ka BP event was a circum‐North Atlantic region cold event lasting ∼150 years approximately 8200 years ago and occurred in response to changes in the salinity balance of the North Atlantic Ocean (Barber et al ., ).…”

Section: Introductionmentioning

confidence: 97%

The 8.2‐ka BP event in north‐eastern North America: first combined oxygen and hydrogen isotopic data from peat in Newfoundland

Daley¹,

Barber

Hughes

et al. 2016

J Quaternary Science

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Finding direct evidence for atmospheric circulation change in terrestrial records of Holocene climate variability remains a fundamental challenge. Here we present the first combined stable oxygen and hydrogen isotopic palaeorecord from a peatland core in Newfoundland, Canada. Sphagnum cellulose samples were isolated from a core from Nordan's Pond Bog, Newfoundland, and analysed for dD values. Combined with existing d18 O data, the resulting dD/d 18 O bi-plot correlates directly with existing measurements of the modern (late 20th century) isotopic composition of precipitation from GNIP stations in Nova Scotia and Labrador, implying a close relationship between the estimated isotopic composition of source water used by the mosses and that of the source precipitation. We use the relative variations between the two isotope records to test the hypothesis that atmospheric circulation changed in the millennium following the 8.2-ka BP climate event. The data reveal a secondary complex isotopic response $200 years (8250-8050 a BP) after a primary oxygen isotopic event that is widespread in the north Atlantic region. This secondary event is characterized by a divergence in oxygen and hydrogen isotope records that can most plausibly be explained by the augmentation of precipitation moisture from a more distant and more continental vapour source.

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Proxy benchmarks for intercomparison of 8.2 ka simulations

Cited by 10 publications

References 48 publications

Climate response to the 8.2 ka event in coastal California

Climate response to the 8.2 ka event in coastal California

Magnitude of the 8.2 ka event freshwater forcing based on stable isotope modelling and comparison to future Greenland melting

The 8.2‐ka BP event in north‐eastern North America: first combined oxygen and hydrogen isotopic data from peat in Newfoundland

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