The importance of Canadian Arctic Archipelago gateways for glacial expansion in Scandinavia

Löfverström, Marcus; Thompson, D. M.; Otto‐Bliesner, Bette L.; Brady, Esther C.

doi:10.1038/s41561-022-00956-9

Cited by 16 publications

(9 citation statements)

References 63 publications

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“…This is perhaps related to the annually averaging ignoring seasonal fluctuations. Since we use only LGM and PI time slices, and only interpolate not simulate the climate, we do not capture threshold behaviour such as the closure of the Canadian Artic Archipelago gateways (Löfverström et al, 2022) or processes not captured in LGM and PI time slices such as Dansgaard/Oeschger and Heinrich events and their impact on climate (Claussen et al, 2003). To capture this, transient GCM simulation are required rather than any temporal interpolation method as used here.…”

Section: Discussionmentioning

confidence: 99%

Interactions between the Northern-Hemisphere ice sheets and climate during the Last Glacial Cycle

Scherrenberg

Berends

Stap

et al. 2022

Preprint

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During the Last Glacial Cycle (LGC), ice sheets covered large parts of Eurasia and North America which resulted in ~120 meters of sea level change. Ice sheet -climate interactions have considerable influence on temperature and precipitation patterns, and therefore need to be included when simulating this time period. Ideally, ice sheet -climate interactions are simulated by a high-resolution earth system model. While these models are capable of simulating climates at a certain point in time, such as the Pre-Industrial (PI) or the Last Glacial Maximum (LGM; 21,000 years ago), a full glacial cycle is currently unfeasible as it requires a too large amount of computation time. Nevertheless, ice-sheet models require forcing that captures the gradual change in climate over time to calculate the accumulation and melt of ice and its effect on ice sheet extent and volume changes.Here we simulate the LGC using an ice sheet model forced by LGM and PI climates. The gradual change in climate is modelled by transiently interpolating between pre-calculated results from a climate model for the LGM and the PI. To assess the influence of ice sheet -climate interactions, we use two different interpolation methods: The climate matrix method, which includes these interactions, and the glacial index method, which does not. To investigate the sensitivity of the results to the prescribed climate forcing, we use the output of several models that are part of the Paleoclimate Modelling Intercomparison Project Phase III (PMIP3). In these simulations, ice volume is prescribed and the climate is reconstructed. Here we test those models by using their climate to drive an ice sheet model over the LGC.We find that the differences caused by the climate forcing exceeds the differences caused by the interpolation method. Some General Circulation Models (GCMs) produced unrealistic LGM volumes and only four resulted in reasonable ice sheets with LGM Northern Hemisphere sea level contribution ranging between 74 -113 meters with respect to the present day. The glacial index and climate matrix methods result in similar ice volumes at LGM but yield a different ice evolution with different ice domes during the inception phase of the glacial cycle, and different sea-level rates during the deglaciation phase. The temperature-albedo feedback is the main cause of differences between the glacial index and climate matrix methods.

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Section: Discussionmentioning

confidence: 99%

Interactions between the Northern-Hemisphere ice sheets and climate during the Last Glacial Cycle

Scherrenberg

Berends

Stap

et al. 2022

Preprint

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“…Also, ocean floor horizons in MIS 3 represent minor ice raft floes from Scandinavia/North Sea, not Hudson Bay (Velay-Vitov, Peltier, and Stuhne, 2020). Lofverstrom (2022) provides a plausible explanation of the shift of the H3 source of IRDs from Hudson Bay to the North Sea. The Sapelo upland of H3 ends at the backbay marsh of H2.…”

Section: Methodsmentioning

confidence: 99%

Emergent Sandy Barriers Formed Sapelo Island (Georgia, U.S.A.) during Heinrich Events and in the Holocene

Marland,

Kjerfve,

Smith

2023

Journal of Coastal Research

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Marland, F.C.; Kjerfve, B., and Smith, J.S., 2023. Emergent sandy barriers formed Sapelo Island (Georgia, U.S.A.) during Heinrich events and in the Holocene. Journal of Coastal Research, 39(6), 1068–1081. Charlotte (North Carolina), ISSN 0749-0208.Sapelo Island's core consists of five separate barrier islands corresponding to five Heinrich events, H5–H1. During the present interglacial rise of the sea, Holocene barriers (H0) were attached to the most recent paleo-barrier, H1. All barriers have a recurved spit with an intervening backbay tidal marsh. Each barrier is composed of several dune ridges. Beach ridge editions were not formed at their present locations. Sand and other materials emerged from below sea level on the shelf in transgressive, elevated H seas and in the last post-glacial rise of the Holocene interglacial. Fourteen spurious increases of higher sea levels of warmer water in Dansgaard-Oeschger (D-O) events were followed by cooling H intervals with extreme waves during gales, hurricanes, and possibly tsunamis. Deltaic surplus materials on the shelf rolled shoreward. Storms drove deposits onshore in predominant wave episodes of overwash. Pliocene and Pleistocene sand surpluses on the continental shelf in relict river channels and deltas were and are source deposits. The preserved varved chronology is based on analyses of pollen and microfossils from Lake Tulane, Florida. Lake Tulane provides a continuous timeline of comparable radiocarbon ages to Sapelo. Both sites are considered coeval. Overwash deposits on the dry sand beach above average tides were forerunners of dune formation. After storms, backshore sand was trapped within strandlines of Spartina marshwrack. Materials caught in the straw mulch on the dry sand produced aeolian dune ridges during windswept Nor'easters. High dunes grew from low and coalesced into a series of barriers to form Sapelo Island.

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“…Further investigations will also consider the Eurasian ice sheets, which show diverse responses in our different simulations, indicating that the mechanism for the Eurasian ice sheet development might be governed by different dynamics, for example, ref. 52.…”

Section: Articlementioning

confidence: 99%

Rapid Laurentide Ice Sheet growth preceding the Last Glacial Maximum due to summer snowfall

Niu,

Knorr,

Krebs-Kanzow

et al. 2024

Nat. Geosci.

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There has been extensive research into the nonlinear responses of the Earth system to astronomical forcing during the last glacial cycle. However, the speed and spatial geometry of ice sheet expansion to its largest extent at the Last Glacial Maximum 21 thousand years ago remains uncertain. Here we use an Earth system model with interactive ice sheets to show that distinct initial North American (Laurentide) ice sheets at 38 thousand years ago converge towards a configuration consistent with the Last Glacial Maximum due to feedbacks between atmospheric circulation and ice sheet geometry. Notably, ice advance speed and spatial pattern in our model are controlled by the amount of summer snowfall, which is dependent on moisture transport pathways from the North Atlantic warm pool linked to ice sheet geometry. The consequence of increased summer snowfall on the surface mass balance of the ice sheet is not only the direct increase in accumulation but the indirect reduction in melt through the snow/ice–albedo feedback. These feedbacks provide an effective mechanism for ice growth for a range of initial ice sheet states and may explain the rapid North American ice volume increase during the last ice age and potentially driving growth during previous glacial periods.

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The importance of Canadian Arctic Archipelago gateways for glacial expansion in Scandinavia

Cited by 16 publications

References 63 publications

Interactions between the Northern-Hemisphere ice sheets and climate during the Last Glacial Cycle

Interactions between the Northern-Hemisphere ice sheets and climate during the Last Glacial Cycle

Emergent Sandy Barriers Formed Sapelo Island (Georgia, U.S.A.) during Heinrich Events and in the Holocene

Rapid Laurentide Ice Sheet growth preceding the Last Glacial Maximum due to summer snowfall

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