Download or read book Modeling Terrestrial Carbon Cycle During the Last Glacial Maximum written by Dan Zhu and published by . This book was released on 2016 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the repeated glacialinterglacialtransitions, there has been aconsistent and partly abrupt increase of nearly100 ppm in atmospheric CO2, indicating majorredistributions among the carbon reservoirs ofland, ocean and atmosphere. A comprehensiveexplanation of the carbon fluxes associatedwith the transitions is still missing, requiring abetter understanding of the potential carbonstock in terrestrial biosphere during the glacialperiod. In this thesis, I aimed to improve theunderstanding of terrestrial carbon stocks andcarbon cycle during the Last Glacial Maximum(LGM, about 21,000 years ago), through aseries of model developments to improve therepresentation of vegetation dynamics,permafrost soil carbon dynamics, andinteractions between large herbivores andvegetation in the ORCHIDEE-MICT landsurface model.For the first part, I improved theparameterization of vegetation dynamics inORCHIDEE-MICT for the northern mid- tohigh-latitude regions, which was evaluatedagainst present-day observation-based datasetsof land cover, gross primary production, andforest biomass. Significant improvements wereshown for the new model version in thedistribution of plant functional types (PFTs),including a more realistic simulation of thenorthern tree limit and of the distribution ofevergreen and deciduous conifers in the borealzone. The revised model was then applied tosimulate vegetation distribution during theLGM, showing a general agreement with thepoint-scale reconstructions based on pollen andplant macrofossil data.Among permafrost (perennially frozen) soils,the thick, ice-rich and organic-rich siltysediments called yedoma deposits hold largequantities of organic carbon, which areremnants of late-Pleistocene carbonaccumulated under glacial climates. In order tosimulate the buildup of the thick frozen carbonin yedoma deposits, I implemented asedimentation parameterization in the soilcarbon module of ORCHIDEE-MICT. Theinclusion of sedimentation allowed the modelto reproduce the vertical distribution of carbonobserved at the yedoma sites, leading toseveral-fold increase in total carbon. Simulatedpermafrost soil carbon stock during the LGMwas ~1550 PgC, among which 390~446 PgCwithin today's known yedoma region (1.3million km2). This result was still anunderestimation since the potentially largerarea of yedoma during the LGM than todaywas not yet taken into account.For the third part, in light of the growingevidence on the ecological impacts of largeanimals, and the potential role of megaherbivoresas a driving force that maintainedthe steppe ecosystems during the glacialperiods, I incorporated a dynamic grazingmodel in ORCHIDEE-MICT, based onphysiological equations for energy intake andexpenditure, reproduction rate, and mortalityrate for wild large grazers. The model showedreasonable results of today's grazer biomasscompared to empirical data in protected areas,and was able to produce an extensive biomewith a dominant vegetation of grass and asubstantial distribution of large grazers duringthe LGM. The effects of large grazers onvegetation and carbon cycle were discussed,including reducing tree cover, enhancinggrassland productivity, and increasing theturnover rate of vegetation living biomass.Lastly, I presented a preliminary estimation ofpotential LGM permafrost carbon stock, afteraccounting for the effects of large grazers, aswell as extrapolations for the spatial extent ofyedoma-like thick sediments based on climaticand topographic features that are similar to theknown yedoma region. Since these results werederived under LGM climate and constantsedimentation rate, a more realistic simulationwould need to consider transient climate duringthe last glacial period and sedimentation ratevariations in the next step.
Download or read book Vegetation and the Terrestrial Carbon Cycle written by David Beerling and published by Cambridge University Press. This book was released on 2001-10-18 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analysis of the Earth's vegetations and carbon cycle in the past and predictions for the future.
Download or read book An Investigation of Carbon Cycle Dynamics Since the Last Glacial Maximum Using a Climate Model of Intermediate Complexity written by Christopher Simmons and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: However, the results imply that external mechanisms leading to a decrease in alkalinity during the Holocene (such as declining weathering rates, more extensive marine ice shelves, terrestrial uptake, more calcifiers, coral reef expansion, etc.) may prevent the ocean from absorbing more of the anthropogenic terrestrial release, allowing the deforestation flux to balance a greater fraction of the Holocene peatland uptake (not modelled) and permitting CO2 to increase from oceanic processes that are normally overwhelmed by northern peatlands. " --
Download or read book Land Carbon Cycle Modeling written by Yiqi Luo and published by CRC Press. This book was released on 2022-08-18 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon moves through the atmosphere, through the oceans, onto land, and into ecosystems. This cycling has a large effect on climate – changing geographic patterns of rainfall and the frequency of extreme weather – and is altered as the use of fossil fuels adds carbon to the cycle. The dynamics of this global carbon cycling are largely predicted over broad spatial scales and long periods of time by Earth system models. This book addresses the crucial question of how to assess, evaluate, and estimate the potential impact of the additional carbon to the land carbon cycle. The contributors describe a set of new approaches to land carbon cycle modeling for better exploring ecological questions regarding changes in carbon cycling; employing data assimilation techniques for model improvement; and doing real- or near-time ecological forecasting for decision support. This book strives to balance theoretical considerations, technical details, and applications of ecosystem modeling for research, assessment, and crucial decision making. Key Features Helps readers understand, implement, and criticize land carbon cycle models Offers a new theoretical framework to understand transient dynamics of land carbon cycle Describes a suite of modeling skills – matrix approach to represent land carbon, nitrogen, and phosphorus cycles; data assimilation and machine learning to improve parameterization; and workflow systems to facilitate ecological forecasting Introduces a new set of techniques, such as semi-analytic spin-up (SASU), unified diagnostic system with a 1-3-5 scheme, traceability analysis, and benchmark analysis, for model evaluation and improvement Related Titles Isabel Ferrera, ed. Climate Change and the Oceanic Carbon Cycle: Variables and Consequences (ISBN 978-1-774-63669-5) Lal, R. et al., eds. Soil Processes and the Carbon Cycle (ISBN 978-0-8493-7441-8) Windham-Myers, L., et al., eds. A Blue Carbon Primer: The State of Coastal Wetland Carbon Science, Practice and Policy (ISBN 978-0-367-89352-1)
Download or read book Carbon Cycle Variability During the Last Millennium and Last Deglaciation written by Thomas K. Bauska and published by . This book was released on 2013 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: The exchange of carbon on earth is one of the fundamental processes that sustains life and regulates climate. Since the onset of the Industrial Revolution, the burning of fossil fuels and anthropogenic land conversion have altered the carbon cycle, increasing carbon dioxide in the atmosphere to levels that are unprecedented in the last 800,000 years. This rapid rise in atmospheric carbon dioxide is driving current climate change and further increases are projected to dominate future climate change. However, the fate of the carbon cycle in response to climate change remains uncertain. Insight into how the carbon cycle may change in the future can come from an understanding how it has changed in the past. Key constraints on past carbon cycle variability come from the concentration and stable isotopic composition of atmospheric carbon dioxide recorded in polar ice cores, but reconstructing these histories has been a significant analytical challenge. This thesis presents a new, more precise method for measuring the stable isotopic composition of carbon in carbon dioxide ([delta]13C of CO2) from polar ice. The new method is then used to reconstruct the atmospheric history of [delta]13C of CO2 during the last millennium (~770-1900 C.E.) and last deglaciation (~20,000-10,000 years before present). Previously, methods for measuring the [delta]13C of CO2 had been limited to precision of greater than ±0.05[per mil]. The method presented here combines an ice grater air extraction method and micro-volume equipped dual-inlet mass spectrometer to make high-precision measurements on very small samples of fossil CO2. The precision as determined by replicate analysis is ±0.018[per mil]. The method also provides high-precision measurements of the CO2 (±2 ppm) and N2O (±4 ppb). A new high-resolution (~20 year spacing) record of the [delta]13C of CO2 from 770-1900 C.E is presented that suggests land carbon controlled atmospheric CO2 variability prior to the Industrial Revolution. A deconvolution of the CO2 fluxes to the atmosphere provides a well-constrained estimate of the evolution of land carbon stocks. The relationship between climate and land carbon for this time period constrains future climate-carbon cycle sensitivity, but an additional process affecting land carbon is required to explain the data. This missing process may be related to early anthropogenic land cover change or patterns of drought. A long-standing problem in the field of paleoclimatology is a complete mechanistic understanding of the 80 ppm increase in atmospheric CO2 during the last deglaciation. A horizontal ice core on the Taylor Glacier in Antarctica allowed for the recovery of well-dated, large ice samples spanning the last deglaciation. From this unique archive, a new [delta]13C of CO2 of very high resolution (50-150 year spacing) is reconstructed. A box model of the carbon cycle is used to construct a framework of the evolution of the carbon cycle during deglaciation. During the Last Glacial Maximum, the lower CO2 concentration accompanied by only a minor shift in [delta]13C of CO2 relative to the early Holocene is consistent with a more efficient biological pump in the Southern ocean, limited air-sea gas exchange around Antarctica, and colder ocean temperatures. The temporal evolution of these factors, as informed by timing of proxy data, reconciles the non-linear relationship between CO2 and [delta]13C of CO2 from the Last Glacial Maximum to the pre-Industrial. However, the data also reveal very fast changes in [delta]13C of CO2 that suggest a rapid emission of depleted carbon to the atmosphere on the centennial timescale that is not captured in current models.
Download or read book Climate Change and Terrestrial Ecosystem Modeling written by Gordon Bonan and published by Cambridge University Press. This book was released on 2019-02-21 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides an essential introduction to modeling terrestrial ecosystems in Earth system models for graduate students and researchers.
Download or read book Vegetation and the Terrestrial Carbon Cycle written by D. J. Beerling and published by . This book was released on 2001 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using knowledge of present day vegetation processes and models of global climate, the authors simulate and analyse changes in the earth's vegetation and in the capacity of the Earth's carbon cycle over the past 400 million years. Possible conditions in future centuries are also investigated, providing valuable predictions.
Download or read book The Global Carbon Cycle written by Christopher B. Field and published by Island Press. This book was released on 2012-09-26 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: While a number of gases are implicated in global warming, carbon dioxide is the most important contributor, and in one sense the entire phenomena can be seen as a human-induced perturbation of the carbon cycle. The Global Carbon Cycle offers a scientific assessment of the state of current knowledge of the carbon cycle by the world's leading scientists sponsored by SCOPE and the Global Carbon Project, and other international partners. It gives an introductory over-view of the carbon cycle, with multidisciplinary contributions covering biological, physical, and social science aspects. Included are 29 chapters covering topics including: an assessment of carbon-climate-human interactions; a portfolio of carbon management options; spatial and temporal distribution of sources and sinks of carbon dioxide; socio-economic driving forces of emissions scenarios. Throughout, contributors emphasize that all parts of the carbon cycle are interrelated, and only by developing a framework that considers the full set of feedbacks will we be able to achieve a thorough understanding and develop effective management strategies. The Global Carbon Cycle edited by Christopher B. Field and Michael R. Raupach is part of the Rapid Assessment Publication series produced by the Scientific Committee on Problems of the Environment (SCOPE), in an effort to quickly disseminate the collective knowledge of the world's leading experts on topics of pressing environmental concern.
Download or read book Carbon Cycle Research Plan written by Roger C. Dahlman and published by . This book was released on 1984 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Paleoclimatology written by Gilles Ramstein and published by Springer Nature. This book was released on 2020-11-09 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: This two-volume book provides a comprehensive, detailed understanding of paleoclimatology beginning by describing the “proxy data” from which quantitative climate parameters are reconstructed and finally by developing a comprehensive Earth system model able to simulate past climates of the Earth. It compiles contributions from specialists in each field who each have an in-depth knowledge of their particular area of expertise. The first volume is devoted to “Finding, dating and interpreting the evidence”. It describes the different geo-chronological technical methods used in paleoclimatology. Different fields of geosciences such as: stratigraphy, magnetism, dendrochronology, sedimentology, are drawn from and proxy reconstructions from ice sheets, terrestrial (speleothems, lakes, and vegetation) and oceanic data, are used to reconstruct the ancient climates of the Earth. The second volume, entitled “Investigation into ancient climates,” focuses on building comprehensive models of past climate evolution. The chapters are based on understanding the processes driving the evolution of each component of the Earth system (atmosphere, ocean, ice). This volume provides both an analytical understanding of each component using a hierarchy of models (from conceptual to very sophisticated 3D general circulation models) and a synthetic approach incorporating all of these components to explore the evolution of the Earth as a global system. As a whole this book provides the reader with a complete view of data reconstruction and modeling of the climate of the Earth from deep time to present day with even an excursion to include impacts on future climate.
Download or read book Land Carbon Cycle Modeling written by Yiqi Luo and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Carbon moves through the atmosphere, through the oceans, onto land, and into ecosystems. This cycling has a large effect on climate - changing geographic patterns of rainfall and the frequency of extreme weather - and is altered as the use of fossil fuels adds carbon to the cycle. The dynamics of this global carbon cycling are largely predicted over broad spatial scales and long periods of time by Earth system models. This book addresses the crucial question of how to assess, evaluate, and estimate the potential impact of the additional carbon to the land carbon cycle. The contributors describe a set of new approaches to land carbon cycle modeling for better exploring ecological questions regarding changes in carbon cycling; employing data assimilation techniques for model improvement; doing real- or near-time ecological forecasting for decision support; combining newly available machine learning techniques with process-based models to improve prediction of land carbon cycle under climate change. This new edition includes 7 new chapters on machine learning and its applications to carbon cycle research (5 chapters). on principles underlying carbon dioxide removal from the atmosphere (1 chapter), a contemporary active research and management issue, and on community infrastructure for ecological forecasting"--
Download or read book The Global Carbon Cycle written by Martin Heimann and published by Springer. This book was released on 1993 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: Of workshop on interannual variations in the carbon cycle / T. Volk and R. Keeling -- Summary of workshop on dissolved organic carbon in the ocean / J. R. Toggweiler and J. Orr -- Summary of workshop on the relative roles of physics and chemistry in the marine carbon cycle / G. Evans and J. Parslow -- Summary of workshop on terrestrial carbon cycling / I. C. Prentice and W. Emanuel -- Summary of workshop on measurement and modelling of the terrestrial net carbon flux / P. G. Jarvis and R. F. Houghton.
Download or read book Model Studies on the Response of the Terrestrial Carbon Cycle to Climate Change and Variability written by Marko Scholze and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Importance of Terrestrial Rock Weathering as a Negative Feedback Mechanism on the Global Carbon Cycle and Climate written by Marc-Olivier Brault and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis presents a set of model studies of climate interactions with terrestrial rock weathering using the University of Victoria Earth System Climate Model (UVic ESCM); several different sets of weathering parameterizations are investigated within the context of two very important periods of Earth's climatic history. Firstly, we examine the importance of the rock weathering feedback mechanism during the last deglacial period (ca. 16,000 - 4,000 BCE) with four box-model parameterizations of terrestrial weathering. The deglacial climate change in the model was driven by changes in orbital parameters, prescribed atmospheric CO2 variability, and prescribed removal of continental ice sheets. Over the course of the 12,000-year simulation period, increases in weathering provided a mechanism that slowly removes CO2 from the atmosphere, in opposition to the observed atmospheric CO2 increase during this period. These processes were found to transfer both carbon and alkalinity to the ocean, the combination of which resulted in as much as a 1000 Pg C increase in total ocean carbon, relative to a control simulation with constant weathering. However, the rapid expansion of northern Hemisphere vegetation introduced a significant uncertainty among the weathering parameterizations. Further experiments to test the individual impacts of weathering dissolved inorganic carbon and alkalinity fluxes on ocean biogeochemistry suggested that the worldwide distribution of rock types and the ratio of carbonate to silicate weathering may be crucially important in obtaining an accurate estimate of changes in global weathering rates.Secondly, we describe the development and application of a new spatially-explicit weathering scheme. We integrated a dataset of modern-day lithology with a number of previously devised parameterizations for weathering dependency on temperature, primary productivity, and runoff. We tested the model with simulations of future carbon cycle perturbations, comparing a number of emission scenarios and model versions with each other and with zero-dimensional equivalents of each experiment. Overall, we found that our two-dimensional weathering model versions were more efficient in restoring the carbon cycle to its pre-industrial state following the pulse emissions than their zero-dimensional counterparts; however, the effect of this weathering negative feedback on the global carbon cycle was small on timescales of less than 1000 years. According to model results, the largest contribution to future changes in weathering rates came from the expansion of tropical and mid-latitude vegetation in grid cells dominated by weathering-vulnerable rock types; changes in temperature and river runoff had a more modest direct effect. Our results also confirmed that silicate weathering is the only mechanism that can lead to a full recovery of the carbon cycle to pre-industrial levels on multi-millennial timescales.Thirdly, we apply the new weathering parameterization once again to the investigation of future climate changes, but this time following scenarios of representative carbon pathways as presented in the latest IPCC reports. Following on an earlier study which examined the millennial implications of global warming on sea level rise, we come up with a revised assessment of sea level rise taking into account the effect of increased weathering rates on global climate recovery. Based on our model results and interpretation of the impact of temperature on ice sheet melting and sea level rise, we surmise that the impact of rock weathering will not be fast enough to prevent excessive melting of polar ice caps during the next several millennia despite bringing about a much quicker recovery of atmospheric CO2 levels and surface air temperature to pre-industrial levels." --
Download or read book Carbon Cycling in the Glacial Ocean Constraints on the Ocean s Role in Global Change written by Rainer Zahn and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 579 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive progress report on the multi-disciplinary field of ocean and climate change research is given. It compiles introductory background papers and leading scientific results on the ocean-atmosphere carbon cycle with emphasis on the ocean's carbon inventory and the various components involved. The relationship between plankton productivity, carbon fixation, oceanic PCO2 and climate change is investigated from the viewpoint of long-term climatic change during the late Quaternary cycles of ice ages and warm ages. The various approaches range from micropaleontology over organic and trace element geochemistry to molecular isotope geochemistry.
Download or read book Terrestrial Global Productivity written by Jacques Roy and published by Academic Press. This book was released on 2001 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: Trophic levels.
Download or read book Carbon in the Geobiosphere written by Fred T. Mackenzie and published by Springer Science & Business Media. This book was released on 2006-12-29 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book covers the fundamentals of the biogeochemical behavior of carbon near the Earth’s surface. It is mainly a reference text for Earth and environmental scientists. It presents an overview of the origins and behavior of the carbon cycle and atmospheric carbon dioxide, and the human effects on them. The book can also be used for a one-semester course at an intermediate to advanced level addressing the behavior of the carbon and related cycles.
