The Climate of the Last Glacial Maximum: Results from a Coupled Atmosphere-Ocean General Circulation Model Andrew B
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The Last Maximum Ice Extent and Subsequent Deglaciation of the Pyrenees: an Overview of Recent Research
Cuadernos de Investigación Geográfica 2015 Nº 41 (2) pp. 359-387 ISSN 0211-6820 DOI: 10.18172/cig.2708 © Universidad de La Rioja THE LAST MAXIMUM ICE EXTENT AND SUBSEQUENT DEGLACIATION OF THE PYRENEES: AN OVERVIEW OF RECENT RESEARCH M. DELMAS Université de Perpignan-Via Domitia, UMR 7194 CNRS, Histoire Naturelle de l’Homme Préhistorique, 52 avenue Paul Alduy 66860 Perpignan, France. ABSTRACT. This paper reviews data currently available on the glacial fluctuations that occurred in the Pyrenees between the Würmian Maximum Ice Extent (MIE) and the beginning of the Holocene. It puts the studies published since the end of the 19th century in a historical perspective and focuses on how the methods of investigation used by successive generations of authors led them to paleogeographic and chronologic conclusions that for a time were antagonistic and later became complementary. The inventory and mapping of the ice-marginal deposits has allowed several glacial stades to be identified, and the successive ice boundaries to be outlined. Meanwhile, the weathering grade of moraines and glaciofluvial deposits has allowed Würmian glacial deposits to be distinguished from pre-Würmian ones, and has thus allowed the Würmian Maximum Ice Extent (MIE) –i.e. the starting point of the last deglaciation– to be clearly located. During the 1980s, 14C dating of glaciolacustrine sequences began to indirectly document the timing of the glacial stades responsible for the adjacent frontal or lateral moraines. Over the last decade, in situ-produced cosmogenic nuclides (10Be and 36Cl) have been documenting the deglaciation process more directly because the data are obtained from glacial landforms or deposits such as boulders embedded in frontal or lateral moraines, or ice- polished rock surfaces. -
Sea Level and Global Ice Volumes from the Last Glacial Maximum to the Holocene
Sea level and global ice volumes from the Last Glacial Maximum to the Holocene Kurt Lambecka,b,1, Hélène Roubya,b, Anthony Purcella, Yiying Sunc, and Malcolm Sambridgea aResearch School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia; bLaboratoire de Géologie de l’École Normale Supérieure, UMR 8538 du CNRS, 75231 Paris, France; and cDepartment of Earth Sciences, University of Hong Kong, Hong Kong, China This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected in 2009. Contributed by Kurt Lambeck, September 12, 2014 (sent for review July 1, 2014; reviewed by Edouard Bard, Jerry X. Mitrovica, and Peter U. Clark) The major cause of sea-level change during ice ages is the exchange for the Holocene for which the direct measures of past sea level are of water between ice and ocean and the planet’s dynamic response relatively abundant, for example, exhibit differences both in phase to the changing surface load. Inversion of ∼1,000 observations for and in noise characteristics between the two data [compare, for the past 35,000 y from localities far from former ice margins has example, the Holocene parts of oxygen isotope records from the provided new constraints on the fluctuation of ice volume in this Pacific (9) and from two Red Sea cores (10)]. interval. Key results are: (i) a rapid final fall in global sea level of Past sea level is measured with respect to its present position ∼40 m in <2,000 y at the onset of the glacial maximum ∼30,000 y and contains information on both land movement and changes in before present (30 ka BP); (ii) a slow fall to −134 m from 29 to 21 ka ocean volume. -
The Cordilleran Ice Sheet 3 4 Derek B
1 2 The cordilleran ice sheet 3 4 Derek B. Booth1, Kathy Goetz Troost1, John J. Clague2 and Richard B. Waitt3 5 6 1 Departments of Civil & Environmental Engineering and Earth & Space Sciences, University of Washington, 7 Box 352700, Seattle, WA 98195, USA (206)543-7923 Fax (206)685-3836. 8 2 Department of Earth Sciences, Simon Fraser University, Burnaby, British Columbia, Canada 9 3 U.S. Geological Survey, Cascade Volcano Observatory, Vancouver, WA, USA 10 11 12 Introduction techniques yield crude but consistent chronologies of local 13 and regional sequences of alternating glacial and nonglacial 14 The Cordilleran ice sheet, the smaller of two great continental deposits. These dates secure correlations of many widely 15 ice sheets that covered North America during Quaternary scattered exposures of lithologically similar deposits and 16 glacial periods, extended from the mountains of coastal south show clear differences among others. 17 and southeast Alaska, along the Coast Mountains of British Besides improvements in geochronology and paleoenvi- 18 Columbia, and into northern Washington and northwestern ronmental reconstruction (i.e. glacial geology), glaciology 19 Montana (Fig. 1). To the west its extent would have been provides quantitative tools for reconstructing and analyzing 20 limited by declining topography and the Pacific Ocean; to the any ice sheet with geologic data to constrain its physical form 21 east, it likely coalesced at times with the western margin of and history. Parts of the Cordilleran ice sheet, especially 22 the Laurentide ice sheet to form a continuous ice sheet over its southwestern margin during the last glaciation, are well 23 4,000 km wide. -
The History of Ice on Earth by Michael Marshall
The history of ice on Earth By Michael Marshall Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age. But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years. In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the polesand there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over. Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain. Snowball Earth 2.4 to 2.1 billion years ago The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms. The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect. -
Modelling the Concentration of Atmospheric CO2 During the Younger Dryas Climate Event
Climate Dynamics (1999) 15:341}354 ( Springer-Verlag 1999 O. Marchal' T. F. Stocker'F. Joos' A. Indermu~hle T. Blunier'J. Tschumi Modelling the concentration of atmospheric CO2 during the Younger Dryas climate event Received: 27 May 1998 / Accepted: 5 November 1998 Abstract The Younger Dryas (YD, dated between 12.7}11.6 ky BP in the GRIP ice core, Central Green- 1 Introduction land) is a distinct cold period in the North Atlantic region during the last deglaciation. A popular, but Pollen continental sequences indicate that the Younger controversial hypothesis to explain the cooling is a re- Dryas cold climate event of the last deglaciation (YD) duction of the Atlantic thermohaline circulation (THC) a!ected mainly northern Europe and eastern Canada and associated northward heat #ux as triggered by (Peteet 1995). This event has been dated by annual layer counting between 12 700$100 y BP and glacial meltwater. Recently, a CH4-based synchroniza- d18 11550$70 y BP in the GRIP ice core (72.6 3N, tion of GRIP O and Byrd CO2 records (West Antarctica) indicated that the concentration of atmo- 37.6 3W; Johnsen et al. 1992) and between 12 940$ 260 !5. y BP and 11 640$ 250 y BP in the GISP2 ice core spheric CO2 (CO2 ) rose steadily during the YD, sug- !5. (72.6 3N, 38.5 3W; Alley et al. 1993), both drilled in gesting a minor in#uence of the THC on CO2 at that !5. Central Greenland. A popular hypothesis for the YD is time. Here we show that the CO2 change in a zonally averaged, circulation-biogeochemistry ocean model a reduction in the formation of North Atlantic Deep when THC is collapsed by freshwater #ux anomaly is Water by the input of low-density glacial meltwater, consistent with the Byrd record. -
The Great Ice Age Owned Public Lands and Natural and Cultural Resources
U.S. Department of the Interior / U.S. Geological Survey____ As the Nation's principal conservation agency, the Department of the Interior has responsibility for most of our nationally The Great Ice Age owned public lands and natural and cultural resources. This includes fostering wise use of our land and water resources, protecting our fish and wildlife, preserving the environ mental and cultural values of our national parks and histor ical places, and providing for the enjoyment of life through outdoor recreation. The Department assesses our energy and mineral resources and works to assure that their development is in the best interests of all our people. The Department also promotes the goals of the Take Pride in America campaign by encouraging stewardship and citizen responsibility for the public lands and promoting citizen participation in their care. The Department also has a major responsibility for American Indian reservation communities and for people who live in Island Territories under U.S. Administration. Blue Glacier, Olympic National Park, Washington. The Great Ice Age land, indicating that conditions somewhat similar to those which produced the Great Ice by Louis L. Ray Age are still operating in polar and subpolar climates. The Great Ice Age, a recent chapter in the Much has been learned about the Great Ice Earth's history, was a period of recurring Age glaciers because evidence of their pres widespread glaciations. During the Pleistocene ence is so widespread and because similar Epoch of the geologic time scale, which conditions can be studied today in Greenland, began about a million or more years ago, in Antarctica, and in many mountain ranges mountain glaciers formed on all continents, where glaciers still exist. -
Animating the Temporal Progression of Cordilleran Deglaciation and Vegetation Succession in the Pacific Northwest During the Late Quaternary Period
Western Washington University Western CEDAR Scholars Week 2017 - Poster Presentations May 17th, 9:00 AM - 12:00 PM Animating the Temporal Progression of Cordilleran Deglaciation and Vegetation Succession in the Pacific Northwest during the late Quaternary Period Henry Haro Western Washington University Follow this and additional works at: https://cedar.wwu.edu/scholwk Part of the Environmental Studies Commons, and the Higher Education Commons Haro, Henry, "Animating the Temporal Progression of Cordilleran Deglaciation and Vegetation Succession in the Pacific Northwest during the late Quaternary Period" (2017). Scholars Week. 20. https://cedar.wwu.edu/scholwk/2017/Day_one/20 This Event is brought to you for free and open access by the Conferences and Events at Western CEDAR. It has been accepted for inclusion in Scholars Week by an authorized administrator of Western CEDAR. For more information, please contact [email protected]. Animating the Temporal Progression of Cordilleran Deglaciation in the Pacific Northwest during the late Quaternary Period Henry Haro – 2017 The Cordilleran Ice Sheet Sequential Progression of Cordilleran Retreat The topography of the Pacific Northwest, its fjords, inland waterways and islands, are a result of an extended period of glaciation and glacial retreat. This retreat influenced the physical features and the resulting succession of vegetation that led to the landscape we see today. Despite this importance of the Cordilleran ice sheet and the large volume of research on the topic, there lacks a good detailed animation of the movement of the entire ice sheet from the last glacial maximum to the present day. In this study, I used spatial data of the glacial extent at different periods of time during the Quaternary period to model and animate the movement of the Cordilleran ice sheet as it retreated from 18,000 BCE to 10,000 BCE. -
Pleistocene - the Ice Ages
Pleistocene - the Ice Ages Sleeping Bear Dunes National Lakeshore Pleistocene - the Ice Ages • Stage is now set to understand the nature of flora and vegetation of North America and Great Lakes • Pliocene (end of Tertiary) - most genera had already originated (in palynofloras) • Flora was in place • Vegetation units (biomes) already derived Pleistocene - the Ice Ages • In the Pleistocene, earth experienced intensification towards climatic cooling • Culminated with a series of glacial- interglacial cycles • North American flora and vegetation profoundly influenced by these “ice-age” events Pleistocene - the Ice Ages What happened in the Pleistocene? 18K ya • Holocene (Recent) - the present interglacial started ~10,000 ya • Wisconsin - the last glacial (Würm in Europe) occurred between 115,000 ya - 10,000 ya • Height of Wisconsin glacial activity (most intense) was 18,000 ya - most intense towards the end of the glacial period Pleistocene - the Ice Ages What happened in the Pleistocene? • up to 100 meter drop in sea level worldwide • coastal plains become extensive • continental islands disappeared and land bridges exposed 100 m line Beringia Pleistocene - the Ice Ages What happened in the Pleistocene? • up to 100 meter drop in sea level worldwide • coastal plains become extensive • continental islands disappeared and land bridges exposed Malaysia to Asia & New Guinea and New Caledonia to Australia Present Level 100 m Level Pleistocene - the Ice Ages What happened in the Pleistocene? • up to 100 meter drop in sea level worldwide • coastal -
Climate Investigations Using Ice Sheet and Mass Balance Models with Emphasis on North American Glaciation Sean David Birkel
The University of Maine DigitalCommons@UMaine Electronic Theses and Dissertations Fogler Library 2010 Climate Investigations Using Ice Sheet and Mass Balance Models with Emphasis on North American Glaciation Sean David Birkel Follow this and additional works at: http://digitalcommons.library.umaine.edu/etd Part of the Glaciology Commons Recommended Citation Birkel, Sean David, "Climate Investigations Using Ice Sheet and Mass Balance Models with Emphasis on North American Glaciation" (2010). Electronic Theses and Dissertations. 97. http://digitalcommons.library.umaine.edu/etd/97 This Open-Access Dissertation is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of DigitalCommons@UMaine. CLIMATE INVESTIGATIONS USING ICE SHEET AND MASS BALANCE MODELS WITH EMPHASIS ON NORTH AMERICAN GLACIATION By Sean David Birkel B.S. University of Maine, 2002 M.S. University of Maine, 2004 A THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy (in Earth Sciences) The Graduate School The University of Maine December, 2010 Advisory Committee: Peter O. Koons, Professor of Earth Sciences, Advisor George H. Denton, Libra Professor of Earth Sciences, Co-advisor Fei Chai, Professor of Oceanography James L. Fastook, Professor of Computer Science Brenda L. Hall, Professor of Earth Science Terrence J. Hughes, Professor Emeritus of Earth Science ©2010 Sean David Birkel All Rights Reserved iii CLIMATE INVESTIGATIONS USING ICE SHEET AND MASS BALANCE MODELS WITH EMPHASIS ON NORTH AMERICAN GLACIATION By Sean D. Birkel Thesis Advisor: Dr. Peter O. Koons An Abstract of the Dissertation Presented in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy (in Earth Sciences) December, 2010 This dissertation describes the application of the University of Maine Ice Sheet Model (UM-ISM) and Environmental Change Model (UM-ECM) to understanding mechanisms of ice-sheet/climate integration during ice ages. -
Glacial/Interglacial Variations in Atmospheric Carbon Dioxide
review article Glacial/interglacial variations in atmospheric carbon dioxide Daniel M. Sigman* & Edward A. Boyle² * Department of Geosciences, Guyot Hall, Princeton University, Princeton, New Jersey 08544, USA ² Department of Earth, Atmospheric, and Planetary Sciences, Room E34-258, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Massachusetts 02139, USA ............................................................................................................................................................................................................................................................................ Twenty years ago, measurements on ice cores showed that the concentration of carbon dioxide in the atmosphere was lower during ice ages than it is today. As yet, there is no broadly accepted explanation for this difference. Current investigations focus on the ocean's `biological pump', the sequestration of carbon in the ocean interior by the rain of organic carbon out of the surface ocean, and its effect on the burial of calcium carbonate in marine sediments. Some researchers surmise that the whole-ocean reservoir of algal nutrients was larger during glacial times, strengthening the biological pump at low latitudes, where these nutrients are currently limiting. Others propose that the biological pump was more ef®cient during glacial times because of more complete utilization of nutrients at high latitudes, where much of the nutrient supply currently goes unused. We present a version of the latter hypothesis that focuses on the open ocean surrounding Antarctica, involving both the biology and physics of that region. he past two million years have been characterized by of these mechanisms with data from the recent geological and large cyclic variations in climate and glaciation. During glaciological record has been a challenging and controversial task, cold `ice age' periods, large continental ice sheets cover leading as yet to no consensus on a fundamental mechanism. -
How Did Marine Isotope Stage 3 and Last Glacial Maximum Climates Differ? – Perspectives from Equilibrium Simulations
Clim. Past, 5, 33–51, 2009 www.clim-past.net/5/33/2009/ Climate © Author(s) 2009. This work is distributed under of the Past the Creative Commons Attribution 3.0 License. How did Marine Isotope Stage 3 and Last Glacial Maximum climates differ? – Perspectives from equilibrium simulations C. J. Van Meerbeeck1, H. Renssen1, and D. M. Roche1,2 1Department of Earth Sciences - Section Climate Change and Landscape Dynamics, Faculty of Earth and Life Sciences, VU University Amsterdam, de Boelelaan 1085, 1081HV Amsterdam, The Netherlands 2Laboratoire des Sciences du Climat et de l’Environnement (LSCE/IPSL), Laboratoire CEA/INSU-CNRS/UVSQ, C.E. de Saclay, Orme des Merisiers Bat. 701, 91190 Gif sur Yvette Cedex, France Received: 15 August 2008 – Published in Clim. Past Discuss.: 6 October 2008 Revised: 14 January 2009 – Accepted: 20 February 2009 – Published: 5 March 2009 Abstract. Dansgaard-Oeschger events occurred frequently mimics stadials over the North Atlantic better than both con- during Marine Isotope Stage 3 (MIS3), as opposed to the fol- trol experiments, which might crudely estimate interstadial lowing MIS2 period, which included the Last Glacial Max- climate. These results suggest that freshwater forcing is nec- imum (LGM). Transient climate model simulations suggest essary to return climate from warm interstadials to cold sta- that these abrupt warming events in Greenland and the North dials during MIS3. This changes our perspective, making the Atlantic region are associated with a resumption of the Ther- stadial climate a perturbed climate state rather than a typical, mohaline Circulation (THC) from a weak state during sta- near-equilibrium MIS3 climate. -
Observed Climate Variations and Change
7 Observed Climate Variations and Change C.K. FOLLAND, T.R. KARL, K.YA. VINNIKOV Contributors: J.K. Angell; P. Arkin; R.G. Barry; R. Bradley; D.L. Cadet; M. Chelliah; M. Coughlan; B. Dahlstrom; H.F. Diaz; H Flohn; C. Fu; P. Groisman; A. Gruber; S. Hastenrath; A. Henderson-Sellers; K. Higuchi; P.D. Jones; J. Knox; G. Kukla; S. Levitus; X. Lin; N. Nicholls; B.S. Nyenzi; J.S. Oguntoyinbo; G.B. Pant; D.E. Parker; B. Pittock; R. Reynolds; C.F. Ropelewski; CD. Schonwiese; B. Sevruk; A. Solow; K.E. Trenberth; P. Wadhams; W.C Wang; S. Woodruff; T. Yasunari; Z. Zeng; andX. Zhou. CONTENTS Executive Summary 199 7.6 Tropospheric Variations and Change 220 7.6.1 Temperature 220 7.1 Introduction 201 7.6.2 Comparisons of Recent Tropospheric and Surface Temperature Data 222 7.2 Palaeo-Climatic Variations and Change 201 7.6.3 Moisture 222 7.2.1 Climate of the Past 5,000,000 Years 201 7.2.2 Palaeo-climate Analogues for Three Warm 7.7 Sub-Surface Ocean Temperature and Salinity Epochs 203 Variations 222 7.2.2.1 Pliocene climatic optimum (3,000,000 to 4,300,000 BP) 203 7.8 Variations and Changes in the Cryosphere 223 7.2.2.2 Eemian interglacial optimum (125,000 to 7.8.1 Snow Cover 223 130,000 years BP) 204 7.8.2 Sea Ice Extent and Thickness 224 7.2.2.3 Climate of the Holocene optimum (5000 to 7.8.3 Land Ice (Mountain Glaciers) 225 6000 years BP) 204 7.8.4 Permafrost 225 7.9 Variations and Changes in Atmospheric 7.3 The Modern Instrumental Record 206 Circulation 225 7.9.1 El Nino-Southern Oscillation (ENSO) Influences 226 7.4 Surface Temperature Variations and