Articles | Volume 16, issue 12
https://doi.org/10.5194/tc-16-4865-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-16-4865-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be exposure dating
Department of Physical Geography and Geoecology, Charles University,
Albertov 6, 12843 Prague 2, Czech Republic
Department of Physical Geography and Geoecology, Charles University,
Albertov 6, 12843 Prague 2, Czech Republic
John C. Gosse
Department of Earth and Environmental Sciences, Dalhousie University, 1355 Oxford
Street, Halifax B3H 4R2, Nova Scotia, Canada
Alan J. Hidy
Center for Accelerator Mass Spectrometry, Lawrence Livermore National
Laboratory, 7000 East Avenue, Livermore, CA 94550, USA
Alistair J. Monteath
Department of Earth and Atmospheric Sciences, 1–26 Earth Sciences
Building, University of Alberta, Edmonton T6G 2E3, Alberta, Canada
Joseph M. Young
Department of Earth and Atmospheric Sciences, 1–26 Earth Sciences
Building, University of Alberta, Edmonton T6G 2E3, Alberta, Canada
Niall Gandy
Department of the Natural and Built Environment, Sheffield Hallam
University, Sheffield, S1 1WB, UK
School of Earth and Environment, University of Leeds, Leeds LS2 9JT,
UK
Lauren J. Gregoire
School of Earth and Environment, University of Leeds, Leeds LS2 9JT,
UK
Sophie L. Norris
Department of Geography, David Turpin Building, University of
Victoria, Victoria, V8P 5C2, British Columbia, Canada
Duane Froese
CORRESPONDING AUTHOR
Department of Earth and Atmospheric Sciences, 1–26 Earth Sciences
Building, University of Alberta, Edmonton T6G 2E3, Alberta, Canada
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Benjamin J. Stoker, Helen E. Dulfer, Chris R. Stokes, Victoria H. Brown, Christopher D. Clark, Colm Ó Cofaigh, David J. A. Evans, Duane Froese, Sophie L. Norris, and Martin Margold
The Cryosphere, 19, 869–910, https://doi.org/10.5194/tc-19-869-2025, https://doi.org/10.5194/tc-19-869-2025, 2025
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The retreat of the northwestern Laurentide Ice Sheet allows us to investigate how the ice drainage network evolves over millennial timescales and understand the influence of climate forcing, glacial lakes and the underlying geology on the rate of deglaciation. We reconstruct the changes in ice flow at 500-year intervals and identify rapid reorganisations of the drainage network, including variations in ice streaming that we link to climatically driven changes in the ice sheet surface slope.
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Stable isotope data of a precisely dated stalagmite from northwestern Iberia indicate gradual North Atlantic meltwater input during the last glacial maximum, followed by abrupt surges early in the last deglaciation. The first abrupt surge was followed by cooling about 850 years later – unlike later events – which reveals that the Atlantic circulation’s sensitivity to meltwater is variable and related to the evolving background climate boundary conditions.
Takashi Obase, Laurie Menviel, Ayako Abe-Ouchi, Tristan Vadsaria, Ruza Ivanovic, Brooke Snoll, Sam Sherriff-Tadano, Paul J. Valdes, Lauren Gregoire, Marie-Luise Kapsch, Uwe Mikolajewicz, Nathaelle Bouttes, Didier Roche, Fanny Lhardy, Chengfei He, Bette Otto-Bliesner, Zhengyu Liu, and Wing-Le Chan
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Permafrost is at increased risk of thaw due to climate change and anthropogenic disturbances. As permafrost thaws, the microbiomes within these systems may become more active and change in composition, releasing greenhouse gases such as CO2 and CH4. In this study, we determined that permafrost thaw caused by road construction caused permafrost microbiomes to become more similar to surface soils, which has implications for greenhouse gas modelling.
Elisa Ziegler, Nils Weitzel, Jean-Philippe Baudouin, Marie-Luise Kapsch, Uwe Mikolajewicz, Lauren Gregoire, Ruza Ivanovic, Paul J. Valdes, Christian Wirths, and Kira Rehfeld
Clim. Past, 21, 627–659, https://doi.org/10.5194/cp-21-627-2025, https://doi.org/10.5194/cp-21-627-2025, 2025
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During the Last Deglaciation, global surface temperature rose by about 4–7 °C over several millennia. We show that changes in year-to-year up to century-to-century fluctuations of temperature and precipitation during the Deglaciation were mostly larger than during either the preceding or succeeding more stable periods in 15 climate model simulations. The analysis demonstrates how ice sheets, meltwater, and volcanism influence simulated variability to inform future simulation protocols.
Benjamin J. Stoker, Helen E. Dulfer, Chris R. Stokes, Victoria H. Brown, Christopher D. Clark, Colm Ó Cofaigh, David J. A. Evans, Duane Froese, Sophie L. Norris, and Martin Margold
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The retreat of the northwestern Laurentide Ice Sheet allows us to investigate how the ice drainage network evolves over millennial timescales and understand the influence of climate forcing, glacial lakes and the underlying geology on the rate of deglaciation. We reconstruct the changes in ice flow at 500-year intervals and identify rapid reorganisations of the drainage network, including variations in ice streaming that we link to climatically driven changes in the ice sheet surface slope.
Violet L. Patterson, Lauren J. Gregoire, Ruza F. Ivanovic, Niall Gandy, Stephen Cornford, Jonathan Owen, Sam Sherriff-Tadano, and Robin S. Smith
EGUsphere, https://doi.org/10.5194/egusphere-2024-3896, https://doi.org/10.5194/egusphere-2024-3896, 2025
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Simulations of the last two glacial periods are ran using a computer model in which the atmosphere and ice sheets interact. The model is able to produce ice sheet volumes, extents and dynamics in good agreement with data. Sensitivity analysis is undertaken and shows the Northern Hemisphere ice sheet size is particularly sensitive to the albedo of the ice in the model but the different ice sheets display different sensitivities to other processes.
James F. O'Neill, Tamsin L. Edwards, Daniel F. Martin, Courtney Shafer, Stephen L. Cornford, Hélène L. Seroussi, Sophie Nowicki, Mira Adhikari, and Lauren J. Gregoire
The Cryosphere, 19, 541–563, https://doi.org/10.5194/tc-19-541-2025, https://doi.org/10.5194/tc-19-541-2025, 2025
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We use an ice sheet model to simulate the Antarctic contribution to sea level over the 21st century under a range of future climates and varying how sensitive the ice sheet is to different processes. We find that ocean temperatures increase and more snow falls on the ice sheet under stronger warming scenarios. When the ice sheet is sensitive to ocean warming, ocean melt-driven loss exceeds snowfall-driven gains, meaning that the sea level contribution is greater with more climate warming.
Violet L. Patterson, Lauren J. Gregoire, Ruza F. Ivanovic, Niall Gandy, Jonathan Owen, Robin S. Smith, Oliver G. Pollard, Lachlan C. Astfalck, and Paul J. Valdes
Clim. Past, 20, 2191–2218, https://doi.org/10.5194/cp-20-2191-2024, https://doi.org/10.5194/cp-20-2191-2024, 2024
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Simulations of the last two glacial periods are run using a computer model in which the atmosphere and ice sheets interact. The results show that the initial conditions used in the simulations are the primary reason for the difference in simulated North American ice sheet volume between each period. Thus, the climate leading up to the glacial maxima and other factors, such as vegetation, are important contributors to the differences in the ice sheets at the Last and Penultimate glacial maxima.
Alia J. Lesnek, Joseph M. Licciardi, Alan J. Hidy, and Tyler S. Anderson
Geochronology, 6, 475–489, https://doi.org/10.5194/gchron-6-475-2024, https://doi.org/10.5194/gchron-6-475-2024, 2024
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We present an improved workflow for extracting and measuring chlorine isotopes in rocks and minerals. Experiments on seven geologic samples demonstrate that our workflow provides reliable results while offering several distinct advantages over traditional methods. Most notably, our workflow reduces the amount of isotopically enriched chlorine spike used per rock sample by up to 95 %, which will allow researchers to analyze more samples using their existing laboratory supplies.
Sam Sherriff-Tadano, Ruza Ivanovic, Lauren Gregoire, Charlotte Lang, Niall Gandy, Jonathan Gregory, Tamsin L. Edwards, Oliver Pollard, and Robin S. Smith
Clim. Past, 20, 1489–1512, https://doi.org/10.5194/cp-20-1489-2024, https://doi.org/10.5194/cp-20-1489-2024, 2024
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Ensemble simulations of the climate and ice sheets of the Last Glacial Maximum (LGM) are performed with a new coupled climate–ice sheet model. Results show a strong sensitivity of the North American ice sheet to the albedo scheme, while the Greenland ice sheet appeared more sensitive to basal sliding schemes. Our result implies a potential connection between the North American ice sheet at the LGM and the future Greenland ice sheet through the albedo scheme.
Mahya Roustaei, Joel Pumple, Jordan Harvey, and Duane Froese
EGUsphere, https://doi.org/10.5194/egusphere-2024-1353, https://doi.org/10.5194/egusphere-2024-1353, 2024
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This study investigated the application of CT scanning to tackle the limitations of traditional destructive methods in characterization of permafrost cores. Five different permafrost cores were scanned at resolutions of 65 and 25 μm with new calibration method. The identification of different materials from CT images showed air(gas), ice(excess and pore), and sediments using an Otsu segmentation method. The results were validated by a destructive method(cuboid) and also a non-destructive method.
Izabela Szuman, Jakub Z. Kalita, Christiaan R. Diemont, Stephen J. Livingstone, Chris D. Clark, and Martin Margold
The Cryosphere, 18, 2407–2428, https://doi.org/10.5194/tc-18-2407-2024, https://doi.org/10.5194/tc-18-2407-2024, 2024
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A Baltic-wide glacial landform-based map is presented, filling in a geographical gap in the record that has been speculated about by palaeoglaciologists for over a century. Here we used newly available bathymetric data and provide landform evidence of corridors of fast ice flow that we interpret as ice streams. Where previous ice-sheet-scale investigations inferred a single ice source, our mapping identifies flow and ice margin geometries from both Swedish and Bothnian sources.
Sophie L. Norris, Martin Margold, David J. A. Evans, Nigel Atkinson, and Duane G. Froese
The Cryosphere, 18, 1533–1559, https://doi.org/10.5194/tc-18-1533-2024, https://doi.org/10.5194/tc-18-1533-2024, 2024
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Associated with climate change between the Last Glacial Maximum and the current interglacial period, we reconstruct the behaviour of the southwestern Laurentide Ice Sheet, which covered the Canadian Prairies, using detailed landform mapping. Our reconstruction depicts three shifts in the ice sheet’s dynamics. We suggest these changes resulted from ice sheet thinning triggered by abrupt climatic change. However, we show that regional lithology and topography also play an important role.
Brooke Snoll, Ruza Ivanovic, Lauren Gregoire, Sam Sherriff-Tadano, Laurie Menviel, Takashi Obase, Ayako Abe-Ouchi, Nathaelle Bouttes, Chengfei He, Feng He, Marie Kapsch, Uwe Mikolajewicz, Juan Muglia, and Paul Valdes
Clim. Past, 20, 789–815, https://doi.org/10.5194/cp-20-789-2024, https://doi.org/10.5194/cp-20-789-2024, 2024
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Geological records show rapid climate change throughout the recent deglaciation. The drivers of these changes are still misunderstood but are often attributed to shifts in the Atlantic Ocean circulation from meltwater input. A cumulative effort to understand these processes prompted numerous simulations of this period. We use these to explain the chain of events and our collective ability to simulate them. The results demonstrate the importance of the meltwater amount used in the simulation.
Greg Balco, Alan J. Hidy, William T. Struble, and Joshua J. Roering
Geochronology, 6, 71–76, https://doi.org/10.5194/gchron-6-71-2024, https://doi.org/10.5194/gchron-6-71-2024, 2024
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We describe a new method of reconstructing the long-term, pre-observational frequency and/or intensity of wildfires in forested landscapes using trace concentrations of the noble gases helium and neon that are formed in soil mineral grains by cosmic-ray bombardment of the Earth's surface.
Joel Pumple, Alistair Monteath, Jordan Harvey, Mahya Roustaei, Alejandro Alvarez, Casey Buchanan, and Duane Froese
The Cryosphere, 18, 489–503, https://doi.org/10.5194/tc-18-489-2024, https://doi.org/10.5194/tc-18-489-2024, 2024
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Ice content is a critical variable in the context of thawing permafrost, and permafrost cores provide a means to measure the characteristics of frozen ground; however, these measurements are typically destructive and time intensive. Multi-sensor core logging (MSCL) provides a fast, non-destructive method to image permafrost cores, measure bulk density, and estimate ice content. The use of MSCL will improve existing digital permafrost archives by adding high-quality and reproducible data.
Jacob T. H. Anderson, Toshiyuki Fujioka, David Fink, Alan J. Hidy, Gary S. Wilson, Klaus Wilcken, Andrey Abramov, and Nikita Demidov
The Cryosphere, 17, 4917–4936, https://doi.org/10.5194/tc-17-4917-2023, https://doi.org/10.5194/tc-17-4917-2023, 2023
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Antarctic permafrost processes are not widely studied or understood in the McMurdo Dry Valleys. Our data show that near-surface permafrost sediments were deposited ~180 000 years ago in Pearse Valley, while in lower Wright Valley sediments are either vertically mixed after deposition or were deposited < 25 000 years ago. Our data also record Taylor Glacier retreat from Pearse Valley ~65 000–74 000 years ago and support antiphase dynamics between alpine glaciers and sea ice in the Ross Sea.
Oliver G. Pollard, Natasha L. M. Barlow, Lauren J. Gregoire, Natalya Gomez, Víctor Cartelle, Jeremy C. Ely, and Lachlan C. Astfalck
The Cryosphere, 17, 4751–4777, https://doi.org/10.5194/tc-17-4751-2023, https://doi.org/10.5194/tc-17-4751-2023, 2023
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We use advanced statistical techniques and a simple ice-sheet model to produce an ensemble of plausible 3D shapes of the ice sheet that once stretched across northern Europe during the previous glacial maximum (140,000 years ago). This new reconstruction, equivalent in volume to 48 ± 8 m of global mean sea-level rise, will improve the interpretation of high sea levels recorded from the Last Interglacial period (120 000 years ago) that provide a useful perspective on the future.
Allie Balter-Kennedy, Joerg M. Schaefer, Roseanne Schwartz, Jennifer L. Lamp, Laura Penrose, Jennifer Middleton, Jean Hanley, Bouchaïb Tibari, Pierre-Henri Blard, Gisela Winckler, Alan J. Hidy, and Greg Balco
Geochronology, 5, 301–321, https://doi.org/10.5194/gchron-5-301-2023, https://doi.org/10.5194/gchron-5-301-2023, 2023
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Cosmogenic nuclides like 10Be are rare isotopes created in rocks exposed at the Earth’s surface and can be used to understand glacier histories and landscape evolution. 10Be is usually measured in the mineral quartz. Here, we show that 10Be can be reliably measured in the mineral pyroxene. We use the measurements to determine exposure ages and understand landscape processes in rocks from Antarctica that do not have quartz, expanding the use of this method to new rock types.
Suzanne Robinson, Ruza F. Ivanovic, Lauren J. Gregoire, Julia Tindall, Tina van de Flierdt, Yves Plancherel, Frerk Pöppelmeier, Kazuyo Tachikawa, and Paul J. Valdes
Geosci. Model Dev., 16, 1231–1264, https://doi.org/10.5194/gmd-16-1231-2023, https://doi.org/10.5194/gmd-16-1231-2023, 2023
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We present the implementation of neodymium (Nd) isotopes into the ocean model of FAMOUS (Nd v1.0). Nd fluxes from seafloor sediment and incorporation of Nd onto sinking particles represent the major global sources and sinks, respectively. However, model–data mismatch in the North Pacific and northern North Atlantic suggest that certain reactive components of the sediment interact the most with seawater. Our results are important for interpreting Nd isotopes in terms of ocean circulation.
Michael P. Erb, Nicholas P. McKay, Nathan Steiger, Sylvia Dee, Chris Hancock, Ruza F. Ivanovic, Lauren J. Gregoire, and Paul Valdes
Clim. Past, 18, 2599–2629, https://doi.org/10.5194/cp-18-2599-2022, https://doi.org/10.5194/cp-18-2599-2022, 2022
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To look at climate over the past 12 000 years, we reconstruct spatial temperature using natural climate archives and information from model simulations. Our results show mild global mean warmth around 6000 years ago, which differs somewhat from past reconstructions. Undiagnosed seasonal biases in the data could explain some of the observed temperature change, but this still would not explain the large difference between many reconstructions and climate models over this period.
Suzanne Robinson, Ruza Ivanovic, Lauren Gregoire, Lachlan Astfalck, Tina van de Flierdt, Yves Plancherel, Frerk Pöppelmeier, and Kazuyo Tachikawa
EGUsphere, https://doi.org/10.5194/egusphere-2022-937, https://doi.org/10.5194/egusphere-2022-937, 2022
Preprint archived
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The neodymium (Nd) isotope (εNd) scheme in the ocean model of FAMOUS is used to explore a benthic Nd flux to seawater. Our results demonstrate that sluggish modern Pacific waters are sensitive to benthic flux alterations, whereas the well-ventilated North Atlantic displays a much weaker response. In closing, there are distinct regional differences in how seawater acquires its εNd signal, in part relating to the complex interactions of Nd addition and water advection.
Mae Kate Campbell, Paul R. Bierman, Amanda H. Schmidt, Rita Sibello Hernández, Alejandro García-Moya, Lee B. Corbett, Alan J. Hidy, Héctor Cartas Águila, Aniel Guillén Arruebarrena, Greg Balco, David Dethier, and Marc Caffee
Geochronology, 4, 435–453, https://doi.org/10.5194/gchron-4-435-2022, https://doi.org/10.5194/gchron-4-435-2022, 2022
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We used cosmogenic radionuclides in detrital river sediment to measure erosion rates of watersheds in central Cuba; erosion rates are lower than rock dissolution rates in lowland watersheds. Data from two different cosmogenic nuclides suggest that some basins may have a mixed layer deeper than is typically modeled and could have experienced significant burial after or during exposure. We conclude that significant mass loss may occur at depth through chemical weathering processes.
Helen Mackay, Gill Plunkett, Britta J. L. Jensen, Thomas J. Aubry, Christophe Corona, Woon Mi Kim, Matthew Toohey, Michael Sigl, Markus Stoffel, Kevin J. Anchukaitis, Christoph Raible, Matthew S. M. Bolton, Joseph G. Manning, Timothy P. Newfield, Nicola Di Cosmo, Francis Ludlow, Conor Kostick, Zhen Yang, Lisa Coyle McClung, Matthew Amesbury, Alistair Monteath, Paul D. M. Hughes, Pete G. Langdon, Dan Charman, Robert Booth, Kimberley L. Davies, Antony Blundell, and Graeme T. Swindles
Clim. Past, 18, 1475–1508, https://doi.org/10.5194/cp-18-1475-2022, https://doi.org/10.5194/cp-18-1475-2022, 2022
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We assess the climatic and societal impact of the 852/3 CE Alaska Mount Churchill eruption using environmental reconstructions, historical records and climate simulations. The eruption is associated with significant Northern Hemisphere summer cooling, despite having only a moderate sulfate-based climate forcing potential; however, evidence of a widespread societal response is lacking. We discuss the difficulties of confirming volcanic impacts of a single eruption even when it is precisely dated.
Leah A. VanLandingham, Eric W. Portenga, Edward C. Lefroy, Amanda H. Schmidt, Paul R. Bierman, and Alan J. Hidy
Geochronology, 4, 153–176, https://doi.org/10.5194/gchron-4-153-2022, https://doi.org/10.5194/gchron-4-153-2022, 2022
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This study presents erosion rates of the George River and seven of its tributaries in northeast Tasmania, Australia. These erosion rates are the first measures of landscape change over millennial timescales for Tasmania. We demonstrate that erosion is closely linked to a topographic rainfall gradient across George River. Our findings may be useful for efforts to restore ecological health to Georges Bay by determining a pre-disturbance level of erosion and sediment delivery to this estuary.
Sandra M. Braumann, Joerg M. Schaefer, Stephanie M. Neuhuber, Christopher Lüthgens, Alan J. Hidy, and Markus Fiebig
Clim. Past, 17, 2451–2479, https://doi.org/10.5194/cp-17-2451-2021, https://doi.org/10.5194/cp-17-2451-2021, 2021
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Glacier reconstructions provide insights into past climatic conditions and elucidate processes and feedbacks that modulate the climate system both in the past and present. We investigate the transition from the last glacial to the current interglacial and generate beryllium-10 moraine chronologies in glaciated catchments of the eastern European Alps. We find that rapid warming was superimposed by centennial-scale cold phases that appear to have influenced large parts of the Northern Hemisphere.
Masa Kageyama, Sandy P. Harrison, Marie-L. Kapsch, Marcus Lofverstrom, Juan M. Lora, Uwe Mikolajewicz, Sam Sherriff-Tadano, Tristan Vadsaria, Ayako Abe-Ouchi, Nathaelle Bouttes, Deepak Chandan, Lauren J. Gregoire, Ruza F. Ivanovic, Kenji Izumi, Allegra N. LeGrande, Fanny Lhardy, Gerrit Lohmann, Polina A. Morozova, Rumi Ohgaito, André Paul, W. Richard Peltier, Christopher J. Poulsen, Aurélien Quiquet, Didier M. Roche, Xiaoxu Shi, Jessica E. Tierney, Paul J. Valdes, Evgeny Volodin, and Jiang Zhu
Clim. Past, 17, 1065–1089, https://doi.org/10.5194/cp-17-1065-2021, https://doi.org/10.5194/cp-17-1065-2021, 2021
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The Last Glacial Maximum (LGM; ~21 000 years ago) is a major focus for evaluating how well climate models simulate climate changes as large as those expected in the future. Here, we compare the latest climate model (CMIP6-PMIP4) to the previous one (CMIP5-PMIP3) and to reconstructions. Large-scale climate features (e.g. land–sea contrast, polar amplification) are well captured by all models, while regional changes (e.g. winter extratropical cooling, precipitations) are still poorly represented.
Ilkka S. O. Matero, Lauren J. Gregoire, and Ruza F. Ivanovic
Geosci. Model Dev., 13, 4555–4577, https://doi.org/10.5194/gmd-13-4555-2020, https://doi.org/10.5194/gmd-13-4555-2020, 2020
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The Northern Hemisphere cooled by several degrees for a century 8000 years ago due to the collapse of an ice sheet in North America that released large amounts of meltwater into the North Atlantic and slowed down its circulation. We numerically model the ice sheet to understand its evolution during this event. Our results match data thanks to good ice dynamics but depend mostly on surface melt and snowfall. Further work will help us understand how past and future ice melt affects climate.
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Short summary
The Laurentide Ice Sheet was the largest ice sheet to grow and disappear in the Northern Hemisphere during the last glaciation. In northwestern Canada, it covered the Mackenzie Valley, blocking the migration of fauna and early humans between North America and Beringia and altering the drainage systems. We reconstruct the timing of ice sheet retreat in this region and the implications for the migration of early humans into North America, the drainage of glacial lakes, and past sea level rise.
The Laurentide Ice Sheet was the largest ice sheet to grow and disappear in the Northern...