Download or read book A High resolution Record of Climate Instability Spanning 1 0 Million Years Across the Mid Pleistocene Transition written by Daniel R. Weirauch and published by ProQuest. This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: I use oxygen isotopes of planktonic foraminiferal species Globigerinoides ruber from Ocean Drilling Program (ODP) Site 1058 in the subtropical northwestern Atlantic to construct a high-resolution climate record spanning the mid-Pleistocene transition from ~411 Ka to 1.35 Ma. The main purpose of this study is to analyze climatic instability on both orbital and suborbital scales during a long transitional interval from dominant 41-kyr glacial cycles to more developed 100-kyr cycles. I provide age control based on two different models using Northern Hemisphere summer insolation and the ODP Site 677 G. ruber [delta] 18 O record of Shackleton et al. (1991) as tuning targets. The results indicate that independent of age control, the appearance and recurrence of significant millennial-scale variability with periods between 3 kyr and 8 kyr begins around 800 Ka. At this time, high-amplitude 4 to 8 kyr cycles become more frequent, with the highest amplitude millennial-scale variability occurring at ~420 kyr during the most extreme glacial interval (Marine Isotope Stage, MIS 12) within the length of the record. I believe that the appearance of millennial-scale variability in association with the evolution of 100-kyr glacial cycles and the occurrence of high-amplitude millennial-scale variability during the most extreme glacial interval is consistent with the strong influence of a tall, thick northern ice sheet on atmospheric circulation patterns. In addition, consideration of the long-term trends in the [delta] 18 O record from ODP Site 1058 indicates a dramatic cooling event just after 900 Ka (MIS 22). This excursion is recorded in other regions in the Atlantic and Pacific Oceans supporting a global-scale, large magnitude cooling event during one of the major Pleistocene climate transitions.
Download or read book Early Middle Pleistocene Transitions written by Geological Society of London and published by Geological Society of London. This book was released on 2005 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Early-Middle Pleistocene transition (around 1.2 to 0.5 Ma) marks a profound shift in Earth's climate state. Low-amplitude 41 ka climate cycles, dominating the earlier part of the Pleistocene, gave way progressively to a 100 ka rhythm of increased amplitude that characterizes our present glacial-interglacial world. This volume assesses the biotic and physical response to this transition both on land and in the oceans: indeed it examines the very nature of Quaternary climate change. Milankovitch theory, palaeoceanography using isotopes and microfossils, marine organic geochemistry, tephrochronology, the record of loess and soil deposition, terrestrial vegetational change, and the migration and evolution of hominins as well as other large and small mammals, are all considered. These themes combine to explore the very origins of our present biota.
Download or read book The Physics of Glaciers written by W. S. B. Paterson and published by Elsevier. This book was released on 2016-10-27 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: This updated and expanded version of the second edition explains the physical principles underlying the behaviour of glaciers and ice sheets. The text has been revised in order to keep pace with the extensive developments which have occurred since 1981. A new chapter, of major interest, concentrates on the deformation of subglacial till. The book concludes with a chapter on information regarding past climate and atmospheric composition obtainable from ice cores.
Download or read book Antarctic Climate Evolution written by Fabio Florindo and published by Elsevier. This book was released on 2008-10-10 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antarctic Climate Evolution is the first book dedicated to furthering knowledge on the evolution of the world's largest ice sheet over its ~34 million year history. This volume provides the latest information on subjects ranging from terrestrial and marine geology to sedimentology and glacier geophysics. - An overview of Antarctic climate change, analyzing historical, present-day and future developments - Contributions from leading experts and scholars from around the world - Informs and updates climate change scientists and experts in related areas of study
Download or read book Boric Acid written by Edward John Catanzaro and published by . This book was released on 1970 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CO2 in Seawater Equilibrium Kinetics Isotopes written by R.E. Zeebe and published by Elsevier. This book was released on 2001-10-15 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon dioxide is the most important greenhouse gas after water vapor in the atmosphere of the earth. More than 98% of the carbon of the atmosphere-ocean system is stored in the oceans as dissolved inorganic carbon. The key for understanding critical processes of the marine carbon cycle is a sound knowledge of the seawater carbonate chemistry, including equilibrium and nonequilibrium properties as well as stable isotope fractionation.Presenting the first coherent text describing equilibrium and nonequilibrium properties and stable isotope fractionation among the elements of the carbonate system. This volume presents an overview and a synthesis of these subjects which should be useful for graduate students and researchers in various fields such as biogeochemistry, chemical oceanography, paleoceanography, marine biology, marine chemistry, marine geology, and others.The volume includes an introduction to the equilibrium properties of the carbonate system in which basic concepts such as equilibrium constants, alkalinity, pH scales, and buffering are discussed. It also deals with the nonequilibrium properties of the seawater carbonate chemistry. Whereas principle of chemical kinetics are recapitulated, reaction rates and relaxation times of the carbonate system are considered in details. The book also provides a general introduction to stable isotope fractionation and describes the partitioning of carbon, oxygen, and boron isotopes between the species of the carbonate system. The appendix contains formulas for the equilibrium constants of the carbonate system, mathematical expressions to calculate carbonate system parameters, answers to exercises and more.
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.
Download or read book Polar Environments and Global Change written by Roger G. Barry and published by Cambridge University Press. This book was released on 2018-08-09 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surveys atmospheric, oceanic and cryospheric processes, present and past conditions, and changes in polar environments.
Download or read book Encyclopedia of Paleoclimatology and Ancient Environments written by Vivien Gornitz and published by Springer Science & Business Media. This book was released on 2008-10-31 with total page 1062 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of Springer’s Major Reference Works, this book gives the reader a truly global perspective. It is the first major reference work in its field. Paleoclimate topics covered in the encyclopedia give the reader the capability to place the observations of recent global warming in the context of longer-term natural climate fluctuations. Significant elements of the encyclopedia include recent developments in paleoclimate modeling, paleo-ocean circulation, as well as the influence of geological processes and biological feedbacks on global climate change. The encyclopedia gives the reader an entry point into the literature on these and many other groundbreaking topics.
Download or read book Seneca written by Lucius Annaeus Senenca and published by University of Chicago Press. This book was released on 2021-11-16 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of Seneca’s most significant letters that illuminate his philosophical and personal life. “There is only one course of action that can make you happy. . . . rejoice in what is yours. What is it that is yours? Yourself; the best part of you.” In the year 62, citing health issues, the Roman philosopher Seneca withdrew from public service and devoted his time to writing. His letters from this period offer a window onto his experience as a landowner, a traveler, and a man coping with the onset of old age. They share his ideas on everything from the treatment of enslaved people to the perils of seafaring, and they provide lucid explanations for many key points of Stoic philosophy. This selection of fifty letters brings out the essentials of Seneca’s thought, with much that speaks directly to the modern reader. Above all, they explore the inner life of the individual who proceeds through philosophical inquiry from a state of emotional turmoil to true friendship, self-determination, and personal excellence.
Download or read book Nonlinear and Stochastic Climate Dynamics written by Christian L. E. Franzke and published by Cambridge University Press. This book was released on 2017-01-19 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is now widely recognized that the climate system is governed by nonlinear, multi-scale processes, whereby memory effects and stochastic forcing by fast processes, such as weather and convective systems, can induce regime behavior. Motivated by present difficulties in understanding the climate system and to aid the improvement of numerical weather and climate models, this book gathers contributions from mathematics, physics and climate science to highlight the latest developments and current research questions in nonlinear and stochastic climate dynamics. Leading researchers discuss some of the most challenging and exciting areas of research in the mathematical geosciences, such as the theory of tipping points and of extreme events including spatial extremes, climate networks, data assimilation and dynamical systems. This book provides graduate students and researchers with a broad overview of the physical climate system and introduces powerful data analysis and modeling methods for climate scientists and applied mathematicians.
Download or read book The Anthropocene as a Geological Time Unit written by Jan Zalasiewicz and published by Cambridge University Press. This book was released on 2019-03-07 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews the evidence underpinning the Anthropocene as a geological epoch written by the Anthropocene Working Group investigating it. The book discusses ongoing changes to the Earth system within the context of deep geological time, allowing a comparison between the global transition taking place today with major transitions in Earth history.
Download or read book Understanding Earth s Deep Past written by National Research Council and published by National Academies Press. This book was released on 2011-08-02 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is little dispute within the scientific community that humans are changing Earth's climate on a decadal to century time-scale. By the end of this century, without a reduction in emissions, atmospheric CO2 is projected to increase to levels that Earth has not experienced for more than 30 million years. As greenhouse gas emissions propel Earth toward a warmer climate state, an improved understanding of climate dynamics in warm environments is needed to inform public policy decisions. In Understanding Earth's Deep Past, the National Research Council reports that rocks and sediments that are millions of years old hold clues to how the Earth's future climate would respond in an environment with high levels of atmospheric greenhouse gases. Understanding Earth's Deep Past provides an assessment of both the demonstrated and underdeveloped potential of the deep-time geologic record to inform us about the dynamics of the global climate system. The report describes past climate changes, and discusses potential impacts of high levels of atmospheric greenhouse gases on regional climates, water resources, marine and terrestrial ecosystems, and the cycling of life-sustaining elements. While revealing gaps in scientific knowledge of past climate states, the report highlights a range of high priority research issues with potential for major advances in the scientific understanding of climate processes. This proposed integrated, deep-time climate research program would study how climate responded over Earth's different climate states, examine how climate responds to increased atmospheric carbon dioxide and other greenhouse gases, and clarify the processes that lead to anomalously warm polar and tropical regions and the impact on marine and terrestrial life. In addition to outlining a research agenda, Understanding Earth's Deep Past proposes an implementation strategy that will be an invaluable resource to decision-makers in the field, as well as the research community, advocacy organizations, government agencies, and college professors and students.
Download or read book Middle to Late Pleistocene Paleoenvironmental Reconstructions from Lake El gygytgyn Arctic Russia written by Mary Helen Habicht and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change is a major issue challenging the world today. Our global society faces rising temperatures, variable weather patterns, and rising sea level among other associated issues. Our action (or inaction) to address current changes will have serious ramifications for life on our planet in the coming centuries and millennia. In order to provide context for these present and future changes, we can utilize the paleo record to understand the natural variability of Earth's climate system. One region of the world is changing more rapidly than the global average. Over recent decades, the Arctic has experienced warmer temperatures, reduced sea ice, melting permafrost, and shifts in the amount and seasonality of precipitation. Unfortunately, paleoclimate and environmental records from the terrestrial Arctic, particularly beyond the last 120 ka, are few. This is due to the repeated extensive glaciation of the northern hemisphere high latitudes during the ice ages of the Quaternary. One area of the Arctic, in the Anadyr mountains of Chukotka, has remained unglaciated through the Pleistocene. Lake El'gygytgyn, a meteorite impact crater lake formed 3.6 million years ago lies in this area and so provides a continuous sedimentary sequence from the Mid-Pliocene to present. This dissertation includes four studies of Lake El'gygytgyn sediments over the last 800 thousand years. A variety of biogeochemical and stable isotope proxies are used to reconstruct climate and environmental variability throughout the study interval. These studies provide novel information about the natural variations of terrestrial Arctic climate on glacial-interglacial timescales. Chapter 2 of this dissertation involves the analysis of bacterial membrane lipids called branched glycerol dialkyl glycerol tetraethers (brGDGTs) and plant leaf wax n-alkanes to provide records of relative temperature change and terrestrial vegetation turnover in response to aridity during the glacial-intergacial cycles of the Mid-Pleistocene. Our data suggests that regional temperature is strongly influenced by local summer insolation while aridity changes derive from sea level driven changes in continentality. Comparison of our data with previously published paleoclimate records from Lake El'gygytgyn highlights the difference in proxy response to climatic variables and the utility of a multi-proxy approach. Additionally, we use our extensive records to identify the presence of a global climatic transition, the Mid-Brunhes Event (MBE), for the first time in the terrestrial Arctic. In Chapter 3, we analyze algal lipid biomarkers from the same samples used in Chapter 2. We also incorporate stable carbon and nitrogen isotopes to determine changes in primary production and organic matter preservation in Lake El'gygytgyn across multiple glacial-interglacial cycles. Chapter 4 spans the Holocene and Late Pleistocene (280 ka to present). We use the hydrogen isotopic composition of long chain plant leaf wax n-alkanes to reconstruct temperature and hydroclimate changes. We find that MIS 7 was a stronger interglacial period than MIS 5e in the terrestrial Arctic and attribute the variability in hydrogen isotopes predominantly to temperature and moisture source changes. In Chapter 5, we compare the hydrogen isotope composition of n-alkanes measured in Chapter 4 to the isotopic composition of n-alkanoic acids in the same samples previously analyzed by Wilkie (2012). This is a novel approach for paleoclimate records. Our results indicate that the type of compound selected for analysis can have a significant impact on the paleoclimatic interpretations of a study. Finally in Chapter 6, a summary and avenues for future research are provided. Overall, this dissertation is a testament to the utility of biomarkers and stable isotopes in Arctic lake sediments. Each study provides unique information about the terrestrial Arctic climate during the Quaternary and contributes to our understanding of climatic variability and the dynamics of this sensitive region.
Download or read book The Geologic Record of Climatic Change written by Thomas J. Crowley and published by . This book was released on 1982 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Ocean and Cryosphere in a Changing Climate written by Intergovernmental Panel on Climate Change (IPCC) and published by Cambridge University Press. This book was released on 2022-04-30 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.
Download or read book Ice Ages and Astronomical Causes written by Richard A. Muller and published by Springer Science & Business Media. This book was released on 2002-08-26 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is not possible to understand the present or future climate unless scientists can account for the enormous and rapid cycles of glaciation that have taken place over the last million years, and which are expected to continue into the future. A great deal has happened in the theory of the ice ages over the last decade, and it is now widley accepted that ice ages are driven by changes in the Earth's orbit. The study of ice ages is very inter-disciplinary, covering geology, physics, glaciology, oceanography, atmospheric science, planetary orbit calculations astrophysics and statistics.
