An Interdisciplinary Approach Towards Understanding Late Pleistocene Ice Sheet Change

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An Interdisciplinary Approach Towards Understanding Late Pleistocene Ice Sheet Change

Author : Joshua Cuzzone
Publisher :
ISBN 13 :
Total Pages : 128 pages
Book Rating : 4.:/5 (897 download)

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Book Synopsis An Interdisciplinary Approach Towards Understanding Late Pleistocene Ice Sheet Change by : Joshua Cuzzone

Download or read book An Interdisciplinary Approach Towards Understanding Late Pleistocene Ice Sheet Change written by Joshua Cuzzone and published by . This book was released on 2014 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results presented in this dissertation address a number of questions regarding late Pleistocene and Holocene ice-sheet and climate interactions, spanning disciplines involving paleoclimatology and atmospheric science. These studies use various techniques in geochemistry, climate modeling, and ice-sheet modeling to address ice- sheet response to climate and the attendant interactions between the atmosphere and ice- sheets. An important question in paleoclimatology involves the response of past ice sheets to a warming climate, with the end goal of providing context for understanding the response of future ice sheets to anthropogenic warming. A longstanding question regards the timing and rate of retreat for the Scandinavian Ice Sheet (SIS) during the Holocene. Much work has been done to constrain the retreat of the SIS from the last glacial maximum to the well-defined Younger Dryas moraines, however, little is known regarding the SIS Holocene retreat. Presented is a compilation of 87 10Be surface exposure ages from Sweden and Norway. These ages provide a high-resolution reconstruction of the SIS deglaciation during the Holocene, and allow for close comparison with proxies of temperature and insolation. The results suggest an asymmetric deglaciation of the SIS, with retreat forced by both a warming climate and and ice-sheet dynamics depending on time and location. The record also provides a means for evaluating the SIS contribution to Holocene sea-level rise. Combining this with estimates from the Laurentide Ice Sheet and the Greenland Ice Sheet, our results suggest that ~23 m of residual sea-level rise exists at the start of the Holocene. We suggest an Antarctic source, which has implications for understanding the sensitivity of the Antarctic Ice Sheet to Holocene climate change. Ice-sheets exert a large presence on the overlying atmosphere, with these interactions influencing the general circulation and ultimately the surface mass balance of the ice sheet. Prior work has indicated striking differences in the atmospheric circulation between the LGM and present day. Using a fully coupled climate simulation of the last deglaciation, the atmospheric circulation is studied, with respect to the stationary waves and storm tracks. For this study, we focus on the LIS. Our results show an enhanced stationary wave, forced mechanically by the topography of the LIS along western North America, which provides moisture, driven by enhanced ridging. This mechanism provides a positive feedback, whereby a larger ice sheet drives a more positive wintertime mass balance. Eventually, as the ice sheet melts, this stationary wave weakens, and the moisture flux decreases. Over the eastern LIS, coupled atmosphere and ice-sheet dynamics conspire to weaken the storm track at the LGM. As the ice melts, however, the storm track becomes broader and strengthens. The storm track becomes an efficient means for moisture delivery to the eastern LIS, with this relationship strengthening through the deglaciation. We suggest that enhanced wintertime accumulation from the strengthening storm track may have played a strong role in offsetting summertime ablation along the eastern LIS, and thus may be a reason why the LIS terminated over eastern North America. Another longstanding question in paleoclimatology involves the role of CO2 and insolation on driving the deglaciation of the great Northern hemisphere ice sheets. To investigate this question we one way coupled the 3-dimensional thermomechanical ice- sheet model, Glimmer to climate simulations of the last deglaciation using GENMOM. We first built up a realistic LIS, constrained by the best available reconstructions of the area and volume, by perturbing parameters to obtain the best fit. Once a suitable spun-up LGM LIS was created, we forced the deglaciation of the LIS using climate simulations of the last deglaciation using either varying insolation only, and varying CO2 only. Our results show similar trends in the deglaciation of the LIS relative to simulations of the deglaciation forced with all forcings (CO2 and insolation). Upon further inspection, our results prove that the one way coupling scheme is unable to capture the influence of the separate forcings. Instead, the topography boundary condition used to drive the climate simulations dictates the distribution of heat and moisture, and thus the deglaciation. Our results show that in order to properly simulate the response of the LIS to CO2 and insolation only forcings, an asynchronous coupling scheme or coupled climate-ice-sheet models should be used.

Ice Ages and Interglacials

Author : Donald Rapp
Publisher : Springer Science & Business Media
ISBN 13 : 3540896805
Total Pages : 275 pages
Book Rating : 4.5/5 (48 download)

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Book Synopsis Ice Ages and Interglacials by : Donald Rapp

Download or read book Ice Ages and Interglacials written by Donald Rapp and published by Springer Science & Business Media. This book was released on 2009-08-22 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book studies the history and gives an analysis of extreme climate change on Earth. In order to provide a long-term perspective, the first chapter briefly reviews some of the wild gyrations that occurred in the Earth’s climate hundreds of millions of years ago: snowball Earth and hothouse Earth. Coming closer to modern times, the effects of continental drift, particularly the closing of the Isthmus of Panama are believed to have contributed to the advent of ice ages in the past three million years. This first chapter sets the stage for a discussion of ice ages in the geological recent past (i.e. within the last three million years, with an emphasis on the last few hundred thousand years). The second chapter discusses geological evidence for ice ages – how geologists surmised their existence prior to actual subsurface data that proved the theory. The following two chapters look at ice cores (primarily from Greenland and Antarctica). Chapter 3 discusses how ice core data is processed and Chapter 4 summarizes data obtained from ice cores. Chapter 5 discusses the processing of data obtained from ocean sediments, and summarizes the results, while the following chapter discusses data from other sources, such as "Devil’s Cave." Chapter 7 summarizes the experimental results from Chapters 4, 5, and 6. It provides the foundation for comparison with theories in later chapters. In a perfect world, this data would be totally separate and disconnected from theory. Unfortunately, as the author shows, dating of much of the data was accomplished by "tuning" to the astronomical theory, which introduces circular reasoning. Chapter 8 provides a brief overview of the various theories that have been devised to "explain" the patterns of alternating ice ages and interglacials that have occurred over the past three million years. This serves as an introduction to the following three chapters which presents the astronomical theory in its various manifestations, compare the astronomical theory with data, and then compare other theories with data. Finally, Chapter 12 summarizes what we think we know about ice ages and, more importantly, what we don’t know.

An Interdisciplinary Approach to the Little Ice Age and Its Implications for Global Change Research

Author : Serena Ann Schwartz
Publisher :
ISBN 13 :
Total Pages : 498 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis An Interdisciplinary Approach to the Little Ice Age and Its Implications for Global Change Research by : Serena Ann Schwartz

Download or read book An Interdisciplinary Approach to the Little Ice Age and Its Implications for Global Change Research written by Serena Ann Schwartz and published by . This book was released on 1994 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Late Pleistocene and Holocene Glacier and Climate Change

Author : Shaun Andrew Marcott
Publisher :
ISBN 13 :
Total Pages : 259 pages
Book Rating : 4.:/5 (72 download)

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Book Synopsis Late Pleistocene and Holocene Glacier and Climate Change by : Shaun Andrew Marcott

Download or read book Late Pleistocene and Holocene Glacier and Climate Change written by Shaun Andrew Marcott and published by . This book was released on 2011 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents results from three studies that address major scientific questions in glacial geology and paleoclimatology for the late Pleistocene and Holocene using relatively new geochemical and statistical techniques. Each of the studies attempts to answer a longstanding question in the respective field using geochemical or statistical methods that have not been applied to the problem thus far. A longstanding question in glaciology is the nature and mechanism of the so- called "Heinrich events" of the last ~60 ka. These massive iceberg discharge events into the North Atlantic from the partial breakup of the Laurentide Ice Sheet are identified from distinct ice rafted debris and detrital carbonate layers in marine sediment cores. The mechanism associated with the initiation of these events is commonly thought to be related to internal ice sheet instabilities. However, Heinrich events consistently occur following a long cooling trend that culminates in an extreme cold event, thus suggesting a possible triggering mechanism by climate. Recent modeling work has proposed an oceanic mechanism associated with ocean warming, but no physical evidence has been made available to date. To test this ocean-warming hypothesis, we measured temperature sensitive trace metals and stable isotopes in benthic foraminifera from a sediment core collected in the western North Atlantic that spans the last six Heinrich events and compared our results to climate model simulations using CCSM3. Our results show subsurface warming occurred prior to or coeval with nearly all of the Heinrich events of the last ~60 ka, thus implicating subsurface ocean warming as the main trigger of these rapid breakups of the Laurentide Ice Sheet. In the field of glacial geology a longstanding question has been the timing of alpine glacial advances during the Holocene. A number of studies have interpreted several Holocene glacial advances in western North America, but age control is based largely on relative dating techniques, which have been shown to be in error by up to 10,000 yrs in some cases. Based on 124 10Be surface exposure ages from twenty cirque moraines in ten mountain ranges across western North America, glacier were retreating from moraine positions during the latest Pleistocene or earliest Holocene and not throughout the Holocene epoch as previously assumed, thus requiring a refined interpretation of Holocene glacial activity in western North America and the associated climate forcing. In the field of paleoclimatology a question regarding how global temperature varied over the entirety of the Holocene epoch has remained to be answered for some time. While many temperature reconstructions exist for the last 2000 years, a full Holocene temperature stack does not exist, despite its potential utility of putting modern climate change into a full interglacial perspective. Based on a global composite of 73 proxy based temperature record, a Holocene temperature stack was constructed and used to demonstrate that a general cooling of ~1°C has occurred from the early to mid Holocene and that centennial and millennial scale variability is modest. We account for both temperature calibration and chronologic uncertainties using a Monte Carlo based approach. Our results are consistent with prior reconstructions of the last 2000 years and now allow for a full Holocene temperature perspective for evaluation with present and future climate change.

Determining Late Pleistocene to Early Holocene Deglaciation of the Baltic Ice Lake Through Sedimentological and Geochemical Analysis of IODP Site M0064

Download Determining Late Pleistocene to Early Holocene Deglaciation of the Baltic Ice Lake Through Sedimentological and Geochemical Analysis of IODP Site M0064 PDF Online Free

Author : April Lynn Kelly
Publisher :
ISBN 13 :
Total Pages : 160 pages
Book Rating : 4.:/5 (994 download)

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Book Synopsis Determining Late Pleistocene to Early Holocene Deglaciation of the Baltic Ice Lake Through Sedimentological and Geochemical Analysis of IODP Site M0064 by : April Lynn Kelly

Download or read book Determining Late Pleistocene to Early Holocene Deglaciation of the Baltic Ice Lake Through Sedimentological and Geochemical Analysis of IODP Site M0064 written by April Lynn Kelly and published by . This book was released on 2017 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Aeolian Geomorphology

Author : Ian Livingstone
Publisher : John Wiley & Sons
ISBN 13 : 1118945646
Total Pages : 336 pages
Book Rating : 4.1/5 (189 download)

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Book Synopsis Aeolian Geomorphology by : Ian Livingstone

Download or read book Aeolian Geomorphology written by Ian Livingstone and published by John Wiley & Sons. This book was released on 2019-02-28 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: A revised introduction to aeolian geomorphology written by noted experts in the field The new, revised and updated edition of Aeolian Geomorphology offers a concise and highly accessible introduction to the subject. The text covers the topics of deserts and coastlines, as well as periglacial and planetary landforms. The authors review the range of aeolian characteristics that include soil erosion and its consequences, continental scale dust storms, sand dunes and loess. Aeolian Geomorphology explores the importance of aeolian processes in the past, and the application of knowledge about aeolian geomorphology in environmental management. The new edition includes contributions from eighteen experts from four continents. All the chapters demonstrate huge advances in observation, measurement and mathematical modelling. For example, the chapter on sand seas shows the impact of greatly enhanced and accessible remote sensing and the chapter on active dunes clearly demonstrates the impact of improvements in field techniques. Other examples reveal the power of greatly improved laboratory techniques. This important text: Offers a comprehensive review of aeolian geomorphology Contains contributions from an international panel of eighteen experts in the field Includes the results of the most recent research on the topic Filled with illustrative examples that demonstrate the advances in laboratory approaches Written for students and professionals in the field, Aeolian Geomorphology provides a comprehensive introduction to the topic in twelve new chapters with contributions from noted experts in the field.

Late Pliocene-Early Pleistocene Ecologic Changes in the Arctic Ocean Borderland

Author : Charles Albert Repenning
Publisher :
ISBN 13 :
Total Pages : 48 pages
Book Rating : 4.:/5 (359 download)

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Book Synopsis Late Pliocene-Early Pleistocene Ecologic Changes in the Arctic Ocean Borderland by : Charles Albert Repenning

Download or read book Late Pliocene-Early Pleistocene Ecologic Changes in the Arctic Ocean Borderland written by Charles Albert Repenning and published by . This book was released on 1992 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

A High-resolution Study of a Late Pleistocene Interglacial-glacial Transition and Its Periodicity in Owens Lake, California Core OL-92

Download A High-resolution Study of a Late Pleistocene Interglacial-glacial Transition and Its Periodicity in Owens Lake, California Core OL-92 PDF Online Free

Author : Cassaundra Ashley-Rochelle Meyers
Publisher :
ISBN 13 :
Total Pages : 186 pages
Book Rating : 4.3/5 (121 download)

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Book Synopsis A High-resolution Study of a Late Pleistocene Interglacial-glacial Transition and Its Periodicity in Owens Lake, California Core OL-92 by : Cassaundra Ashley-Rochelle Meyers

Download or read book A High-resolution Study of a Late Pleistocene Interglacial-glacial Transition and Its Periodicity in Owens Lake, California Core OL-92 written by Cassaundra Ashley-Rochelle Meyers and published by . This book was released on 2010 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Life of the Pleistocene Or Glacial Period

Author : Frank Collins Baker
Publisher :
ISBN 13 :
Total Pages : 632 pages
Book Rating : 4.:/5 (5 download)

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Book Synopsis The Life of the Pleistocene Or Glacial Period by : Frank Collins Baker

Download or read book The Life of the Pleistocene Or Glacial Period written by Frank Collins Baker and published by . This book was released on 1920 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Late Glacial and Postglacial Environmental Changes

Author : Ireneo Peter Martini
Publisher : Oxford University Press, USA
ISBN 13 :
Total Pages : 378 pages
Book Rating : 4.:/5 (318 download)

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Book Synopsis Late Glacial and Postglacial Environmental Changes by : Ireneo Peter Martini

Download or read book Late Glacial and Postglacial Environmental Changes written by Ireneo Peter Martini and published by Oxford University Press, USA. This book was released on 1997 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book of contributed papers reconstructs events following the major Paleozoic glaciation, using as analog events during the last 18,000 years. The detailed analysis of present environments aids in understanding what triggered the ancient deglaciations; conversely, the study of the ancient geological record helps to identify factors that influence global environmental change. The syntheses and analyses of Quaternary and older glacial products and events foster a better understanding of those periods in which rapid climatic and environmental changes occurred, and they constitute a ready source of information for analyzing other ancient geological records or constructing models for possible future changes.

Late Pleistocene History of Northeastern New England and Adjacent Quebec

Author : Geological Society of America. Northeastern Section
Publisher : Boulder, Colo. : Geological Society of America
ISBN 13 :
Total Pages : 418 pages
Book Rating : 4.:/5 (321 download)

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Book Synopsis Late Pleistocene History of Northeastern New England and Adjacent Quebec by : Geological Society of America. Northeastern Section

Download or read book Late Pleistocene History of Northeastern New England and Adjacent Quebec written by Geological Society of America. Northeastern Section and published by Boulder, Colo. : Geological Society of America. This book was released on 1985 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Northern Pleistocene of Russia

Author : Valery I. Astakhov
Publisher : Cambridge Scholars Publishing
ISBN 13 : 1527553515
Total Pages : 610 pages
Book Rating : 4.5/5 (275 download)

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Book Synopsis The Northern Pleistocene of Russia by : Valery I. Astakhov

Download or read book The Northern Pleistocene of Russia written by Valery I. Astakhov and published by Cambridge Scholars Publishing. This book was released on 2020-05-28 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection of papers devoted to the Ice Age of northern Russia provides illustrated descriptions of landforms and sediments revealing former ice sheets of the arctic shelf that inundated northern Russia. It shows that a peculiar Siberian type of inland glaciation is inferred from preserved Ice Age features. This type of glacial environment implies arrested landscape evolution in continental climates with fossil glacial ice surviving within the conservative permafrost. The contributions here delve into the problem of the size and age of the last glaciation intensely discussed in the international literature. This is of broad interest because its solution is paramount for global climatic models and the reconstruction of Circum-Arctic paleoenvironments. It is also essential for understanding natural conditions of early human migration into the Arctic. Another point of interest is the book’s discussion of the profound impact of reconstructed glaciers on the tectonic structure and distribution of petroleum reserves.

Treatise on Geomorphology

Author :
Publisher : Academic Press
ISBN 13 : 0080885225
Total Pages : 6392 pages
Book Rating : 4.0/5 (88 download)

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Book Synopsis Treatise on Geomorphology by :

Download or read book Treatise on Geomorphology written by and published by Academic Press. This book was released on 2013-02-27 with total page 6392 pages. Available in PDF, EPUB and Kindle. Book excerpt: The changing focus and approach of geomorphic research suggests that the time is opportune for a summary of the state of discipline. The number of peer-reviewed papers published in geomorphic journals has grown steadily for more than two decades and, more importantly, the diversity of authors with respect to geographic location and disciplinary background (geography, geology, ecology, civil engineering, computer science, geographic information science, and others) has expanded dramatically. As more good minds are drawn to geomorphology, and the breadth of the peer-reviewed literature grows, an effective summary of contemporary geomorphic knowledge becomes increasingly difficult. The fourteen volumes of this Treatise on Geomorphology will provide an important reference for users from undergraduate students looking for term paper topics, to graduate students starting a literature review for their thesis work, and professionals seeking a concise summary of a particular topic. Information on the historical development of diverse topics within geomorphology provides context for ongoing research; discussion of research strategies, equipment, and field methods, laboratory experiments, and numerical simulations reflect the multiple approaches to understanding Earth’s surfaces; and summaries of outstanding research questions highlight future challenges and suggest productive new avenues for research. Our future ability to adapt to geomorphic changes in the critical zone very much hinges upon how well landform scientists comprehend the dynamics of Earth’s diverse surfaces. This Treatise on Geomorphology provides a useful synthesis of the state of the discipline, as well as highlighting productive research directions, that Educators and students/researchers will find useful. Geomorphology has advanced greatly in the last 10 years to become a very interdisciplinary field. Undergraduate students looking for term paper topics, to graduate students starting a literature review for their thesis work, and professionals seeking a concise summary of a particular topic will find the answers they need in this broad reference work which has been designed and written to accommodate their diverse backgrounds and levels of understanding Editor-in-Chief, Prof. J. F. Shroder of the University of Nebraska at Omaha, is past president of the QG&G section of the Geological Society of America and present Trustee of the GSA Foundation, while being well respected in the geomorphology research community and having won numerous awards in the field. A host of noted international geomorphologists have contributed state-of-the-art chapters to the work. Readers can be guaranteed that every chapter in this extensive work has been critically reviewed for consistency and accuracy by the World expert Volume Editors and by the Editor-in-Chief himself No other reference work exists in the area of Geomorphology that offers the breadth and depth of information contained in this 14-volume masterpiece. From the foundations and history of geomorphology through to geomorphological innovations and computer modelling, and the past and future states of landform science, no "stone" has been left unturned!

Reconstruction of the Late Pleistocene and Holocene Geomorphology of Northwest Calvert Island, British Columbia

Author : Jordan Blair Reglin Eamer
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (988 download)

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Book Synopsis Reconstruction of the Late Pleistocene and Holocene Geomorphology of Northwest Calvert Island, British Columbia by : Jordan Blair Reglin Eamer

Download or read book Reconstruction of the Late Pleistocene and Holocene Geomorphology of Northwest Calvert Island, British Columbia written by Jordan Blair Reglin Eamer and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents results from a multi-year interdisciplinary study of the Late Quaternary geomorphic history of northwest Calvert Island, British Columbia, Canada. There is a considerable knowledge gap in the region pertaining to Cordilleran ice cover and extent as well as landscape response to a uniquely stable relative sea-level history. The objective of this study was to reconstruct this regional landscape response to deglaciation including post-LGM ice cover and extent, relative sea-level changes, coastal landform development, and climate and ecological variance. Methods used to inform this reconstruction included airborne lidar, aerial photography interpretation, sedimentary stratigraphy and detailed sedimentology of samples from shovel pits and lake cores, surficial geology and geomorphic mapping, palaeoecological examinations, and the development of a geochronology using radiocarbon and optical dating. To assist with landscape reconstruction, a new method was developed and used to differentiate littoral and aeolian sands in sediment samples that range in age from Mid to Late Holocene by using modern reference samples. The method utilized a standard optical microscope paired with freely available software (ImageJ) to characterize grain shape parameters. The method was tested on nearly 6,000 sand grains from samples of known and hypothesized depositional settings and was able to correctly identify the depositional setting for 76% of the samples. After testing, the method was used to differentiate littoral and aeolian sands in a number of shovel pit, exposure, and core sediment samples to give context to stratigraphic and geomorphic interpretations. A short-lived Late Pleistocene re-advance of Cordilleran ice occurred in the study area, with radiocarbon ages indicating ice advanced to, and then retreated from, the western edge of Calvert Island between 14.2 and 13.8 ka cal BP, respectively. Sedimentological and palaeoecological information that suggests a cold climate and advancing/retreating glacier as well as lidar remote sensing and field-based geomorphic mapping of moraines in the region provide evidence of the re-advance. After ice retreated from the area, a broad suite of geomorphic landforms developed, including flood plains,ivaeolian dunes, beaches, spits, marshes, and tombolos. Coastal reworking was extensive, with progradation rates greater than 1 m a-1 occurring in some locations during the Late Holocene. These data provide the first evidence of a re-advance of the retreating ice sheet margin on the central coast of British Columbia, contribute an important methodology to advance Quaternary reconstructions, and give a unique account of the geomorphic development of a Pacific Northwest coastline that experienced little relative sea-level change over the Late Pleistocene and Holocene. Results help fill a spatial and temporal gap in the landscape history of British Columbia and have implications for climate and sea-level reconstructions, early human migration patterns, and the palaeoenvironment of an understudied area of the Pacific Northwest coast of North America.

Glacial Geology and the Pleistocene Epoch

Author : Richard Foster Flint
Publisher :
ISBN 13 :
Total Pages : 626 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis Glacial Geology and the Pleistocene Epoch by : Richard Foster Flint

Download or read book Glacial Geology and the Pleistocene Epoch written by Richard Foster Flint and published by . This book was released on 1947 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Ocean Temperature Variability During the Late Pleistocene

Author : Jeremy Scott Hoffman
Publisher :
ISBN 13 :
Total Pages : 286 pages
Book Rating : 4.:/5 (96 download)

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Book Synopsis Ocean Temperature Variability During the Late Pleistocene by : Jeremy Scott Hoffman

Download or read book Ocean Temperature Variability During the Late Pleistocene written by Jeremy Scott Hoffman and published by . This book was released on 2016 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation explores one overarching question relevant to the paleoclimate of the latest Pleistocene glacial cycle (approximately the last 130,000 years): “How did spatial and temporal evolution of ocean temperature, both at the surface and interior, relate to other parts of the climate system in the late Pleistocene?” Results from three studies are presented that seek to address longstanding questions in paleoceanography and paleoclimatology for the late Pleistocene using a combination of novel and accepted statistical and geochemical analysis techniques and leveraging comparisons with available global climate model data. The last interglaciation (LIG; ~129-116 ka) was the most recent period in Earth’s history with higher-than-present global sea level (≥6-9 m) under similar-to-preindustrial concentrations of atmospheric CO2. This suggests that additional feedbacks related to albedo, insolation, and ocean overturning circulation may have resulted in the apparent warming required to cause the higher sea level. Our understanding of how much warmer the LIG was relative to the present interglaciation remains uncertain, however, with current estimates suggesting that sea-surface temperatures (SSTs) were 0-2°C warmer than late-20th century average global temperatures. We present a global compilation of proxy-based annual SST spanning the LIG. Using Monte Carlo and Bayesian techniques to propagate uncertainties in age-model and proxy-based SST reconstructions, our results quantify the spatial timing, amplitude, and uncertainty in global and regional SST change during the LIG. Our conclusions suggest that the LIG surface ocean was indistinguishable from the average surface ocean temperatures observed for the last two decades (1995-2014). This may ultimately imply that the Earth is currently committed to ≥6-9m of equilibrium sea-level rise. Although the LIG is not an analogue for present and future climate change due to the large differences in seasonal orbital insolation and absence of anthropogenic greenhouse gas radiative forcing, it provides an opportunity to test the ability of global climate models to simulate the mechanisms and climate feedbacks responsible for the warmer climate and higher global mean sea level during the LIG. However, when forced only by LIG greenhouse gas concentrations and insolation changes, climate models suggest that the annual mean temperature response was not significantly different from preindustrial control simulations. We present the first multi-model and multiscenario ensemble of transient and equilibrium global climate modeling results spanning the LIG. We show, using a novel model-data comparison framework, that these scenario-specific model results exhibit regionally independent agreement with ocean basin-specific proxy-based SST stacks. This result ultimately implies structural uncertainties and/or misrepresentations of climate feedbacks in the existing suite of climate model simulations, or underestimations of additional proxy-based SST uncertainties. Our conclusions suggest a new target LIG time period for future model-data comparisons and highlight the need for higher resolution transient climate modeling of the LIG and its dependence on meltwater input to the high latitude oceans during the preceding deglaciation. Few discoveries have stimulated the paleoclimate community more so than Heinrich events. Nevertheless, the cause of Heinrich events, characterized by a large flux of icebergs sourced from the Hudson Strait Ice Stream into the North Atlantic, remains debated. Commonly attributed to internal ice-sheet instability, the occurrence of Heinrich events during the coldest intervals of the last glacial cycle instead suggests an external climate control. We expand on recent studies that have shown that incursions of warm subsurface waters into the intermediate depth North Atlantic Ocean destabilized an ice shelf fronting the Hudson Strait Ice Stream, causing a Heinrich event. We present new surface- and bottom-water stable isotope, trace metal, and sedimentary records from two cores taken along the Labrador margin that further support subsurface warming as a trigger of Hudson Strait Heinrich events. We further relate these changes to other sediment core records from the North Atlantic and transient deglacial climate modeling results to show that subsurface warming was ubiquitous across the intermediate North Atlantic during the early part of the last deglaciation and was most likely caused by a preceding reduction in the Atlantic Meridional Overturning Circulation.

Human Colonization of the Arctic: The Interaction Between Early Migration and the Paleoenvironment

Author : V.M. Kotlyakov
Publisher : Academic Press
ISBN 13 : 0128135336
Total Pages : 652 pages
Book Rating : 4.1/5 (281 download)

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Book Synopsis Human Colonization of the Arctic: The Interaction Between Early Migration and the Paleoenvironment by : V.M. Kotlyakov

Download or read book Human Colonization of the Arctic: The Interaction Between Early Migration and the Paleoenvironment written by V.M. Kotlyakov and published by Academic Press. This book was released on 2017-09-11 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: Human Colonization of the Arctic: The Interaction Between Early Migration and the Paleoenvironment explores the relationship between humans and the environment during this early time of colonization, utilizing analytical methods from both the social and natural sciences to develop a unique, interdisciplinary approach that gives the reader a much broader understanding of the interrelationship between humanity and the environment. As colonization of the polar region was intermittent and irregular, based on how early humans interacted with the land, this book provides a glance into how humans developed new ways to make the region more habitable. The book applies not only to the physical continents, but also the arctic waters. This is how humans succeeded in crossing the Bering Strait and water area between Canadian Arctic Islands. About 4500 years ago , humans reached the northern extremity of Greenland and were able to live through the months of polar nights by both adapting to, and making, changes in their environment. - Written by pioneering experts who understand the relationship between humans and the environment in the arctic - Addresses why the patterns of colonization were so irregular - Includes coverage of the earliest examples of humans, developing an understanding of ecosystem services for economic development in extreme climates - Covers both terrestrial and aquatic ecosystems