Rapid early Holocene deglaciation of the Laurentide ice sheet

Carlson, Anders E.; LeGrande, Allegra N.; Oppo, Delia W; Came, Rosemarie E; Schmidt, Gavin A.; Anslow, F. S.; Licciardi, Joseph M.; Obbink, E. A.

doi:10.1038/ngeo285

Cited by 286 publications

(278 citation statements)

References 27 publications

(45 reference statements)

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“…Within the resolution of our data, we cannot confidently resolve rates of sea level change over shorter periods of time. These values are consistent with Carlson et al (2008)'s estimates of the rate of the contribution of the Laurentide Ice Sheet meltwater to global sea level during the early Holocene; they estimate a Laurentide contribution of about 7 m/ky during the period when global sea level climbed above −10 m.…”

Section: Rates Of Sea Level Changesupporting

confidence: 79%

Probabilistic assessment of sea level during the last interglacial stage

Kopp¹,

Simons²,

Mitrovica³

et al. 2009

Nature

698

578

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The Last Interglacial (LIG) stage (ca. 130-115 ka), with polar temperatures likely 3-5 • C warmer than today, serves as a partial analogue for low-end future warming scenarios. Multiple indicators suggest that LIG global sea level (GSL) was higher than at present; based upon a small set of local sea level indicators, the Intergovernmental Panel on Climate Change (IPCC)'s Fourth Assessment Report inferred an elevation of approximately 4-6 m. While this estimate may be correct, it is based upon overly simplistic assumptions about the relationship between local sea level and global sea level. Sea level is often viewed as a simple function of changing global ice volume. This perspective neglects local variability, which arises from several factors, including the distortion of the geoid and the elastic and isostatic deformation of the solid Earth by shifting ice masses. Accurate reconstruction of past global and local sea levels, as well as ice sheet volumes, therefore requires integrating globally distributed data sets of local sea level indicators. To assess the robustness of the IPCC's global estimate and search for patterns in local sea level that are diagnostic of meltwater sources, we have compiled a comprehensive database that includes a variety of local sea level indicators from 47 localities, as well as a global sea level record derived from oxygen isotopes. We generate a global synthesis from these data using a novel statistical approach that couples Gaussian process regression to Markov Chain Monte Carlo simulation of geochronological errors. Our analysis strongly supports the hypothesis that global sea level during the Last Interglacial was higher than today, probably peaking between 6-9 m above the present level. This level is close to that expected from the complete melting of the Greenland Ice Sheet, or from major melting of both the Greenland and West Antarctic Ice Sheets. In the period when sea level was within 10 m of the modern value, the fastest rate of sea level rise sustained for a 1 ky period was likely about 80-110 cm per century. Combined with the evidence for mildly higher temperatures during the LIG, our results highlight the vulnerability of ice sheets to even relatively low levels of sustained global warming.

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Section: Rates Of Sea Level Changesupporting

confidence: 79%

Probabilistic assessment of sea level during the last interglacial stage

Kopp¹,

Simons²,

Mitrovica³

et al. 2009

Nature

698

578

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“…Isotope-enabled GCMs have been used to simulate the geographic distribution of oxygen isotope values in precipitation (Carlson et al, 2008a;LeGrande et al, 2006;Pausata et al, 2011;Risi et al, 2010;Ullman et al, 2014;Werner et al, 2011;Yoshimura et al, 2008). Paleohydrologic records and modeling studies of North America from the LGM show that westerly storm tracks were shifted southward and intensified during the LGM (Oster et al, 2015, and references therein), and d 18 O records also indicate that precipitation was up to 7‰ more negative during glacial intervals .…”

Section: Lis Melting Historymentioning

confidence: 99%

“…In addition, global circulation models (GCMs) that incorporate Rayleigh-type fractionation (Carlson et al, 2008a;LeGrande et al, 2006;Pausata et al, 2011;Risi et al, 2010;Ullman et al, 2014;Werner et al, 2011;Yoshimura et al, 2008) can estimate oxygen isotope heterogeneity in precipitation. These types of models offer an alternative approach to modeling ice-sheet heterogeneity, and recent efforts have begun to link modeled d 18 O w of Pleistocene precipitation with LIS-derived groundwater measurements (Ferguson and Jasechko, 2015).…”

Section: Introductionmentioning

confidence: 99%

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Vetter

Spero

Eggins

et al. 2017

Quaternary Science Reviews

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a b s t r a c tWe present a new method that quantifies the oxygen isotope geochemistry of Laurentide ice-sheet (LIS) meltwater across the last deglaciation, and reconstruct decadal-scale variations in the d 18 O of LIS meltwater entering the Gulf of Mexico between~18 and 11 ka. We employ a technique that combines laser ablation ICP-MS (LA-ICP-MS) and oxygen isotope analyses on individual shells of the planktic values of Mississippi River discharge from discrete core intervals range from À22‰ to À38‰ VSMOW. These values suggest a dynamic melting history of different parts of the LIS, with potential contributions to Mississippi River outflow from both the low-elevation, southern margin of the LIS and high-elevation, high-latitude domes in the LIS interior that were transported to the ablation zone. Prior to~15.5 ka, the d 18 O water value of the Mississippi River was similar to that of regional precipitation or low-latitude LIS meltwater, but the Ba concentration in the Mississippi basin was affected by changes in weathering within the watershed, complicating Ba-salinity relationships in the Gulf of Mexico. After 13 ka, our data suggest Mississippi River outflow did not influence surface salinity above our Gulf of Mexico Orca Basin core site. Rather, we hypothesize that open ocean conditions prevailed as sea level rose and the paleoshoreline at the southern edge of North America retreated northward.

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“…The presence of a broad multi-century background cooling anomaly over the North Atlantic region prior to the drainage of Lake Agassiz/Ojibway is also recorded in numerous other Northern hemisphere records [e.g., Rohling and Pälike, 2005]. During this interval, orbitally induced insolation, summer melt rates in the Canadian high Arctic and freshwater export from the remnant Northern Hemisphere ice sheets, in particular the LIS, were enhanced and resulted in rapid surface ocean freshening and a sea level rise of 6.6 ± 0.8 m at a rate of ∼1.3 cm yr −1 [Carlson et al, 2008;Cronin et al, 2007;Koerner and Fisher, 1990]. While an increase in insolation may thus favor melting of northern ice sheets by warmer summer time temperatures in high latitudes, the resulting freshwater input effectively cooled and freshened the surface ocean in the North Atlantic region.…”

Section: Early Holocene Coolingmentioning

confidence: 87%

Reduced North Atlantic Central Water formation in response to early Holocene ice‐sheet melting

Bamberg

Rosenthal

Paul

et al. 2010

Geophysical Research Letters

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[1] Central waters of the North Atlantic are fundamental for ventilation of the upper ocean and are also linked to the strength of the Atlantic Meridional Overturning Circulation (AMOC). Here, we show based on benthic foraminiferal Mg/Ca ratios, that during times of enhanced melting from the Laurentide Ice Sheet (LIS) between 9.0-8.5 thousand years before present (ka) the production of central waters weakened the upper AMOC resulting in a cooling over the Northern Hemisphere. Centered at 8.54 ± 0.2 ka and 8.24 ± 0.1 ka our dataset records two ∼150-year cooling events in response to the drainage of Lake Agassiz/Ojibway, indicating early slow-down of the upper AMOC in response to the initial freshwater flux into the subpolar gyre (SPG) followed by a more severe weakening of both the upper and lower branches of the AMOC at 8.2 ka. These results highlight the sensitivity of regional North Atlantic climate change to the strength of central-water overturning and exemplify the impact of both gradual and abrupt freshwater fluxes on eastern SPG surface water convection. In light of the possible future increase in Greenland Ice Sheet melting due to global warming these findings may help us to better constrain and possibly predict future North Atlantic climate change. Citation:

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Rapid early Holocene deglaciation of the Laurentide ice sheet

Cited by 286 publications

References 27 publications

Probabilistic assessment of sea level during the last interglacial stage

Probabilistic assessment of sea level during the last interglacial stage

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Reduced North Atlantic Central Water formation in response to early Holocene ice‐sheet melting

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