Download or read book Consequences of Considering Carbon nitrogen Interactions on the Feedbacks Between Climate and the Terrestrial Carbon Cycle written by Andrei P. Sokolov and published by . This book was released on 2007 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: (cont.) Our simulations also show that consideration of carbon/nitrogen interactions not only limits the effect of CO2 fertilization in the absence of climate change, but also changes the sign of the carbon feedback with climate change. In the simulations with the carbon-only version of TEM, surface warming significantly reduces carbon sequestration in both vegetation and soil, leading to a positive carbon-cycle feedback to the climate system. However, in simulations with standard TEM, the increased decomposition of soil organic matter with higher temperatures releases soil nitrogen to stimulate plant growth and carbon storage in the vegetation that is greater than the carbon lost from soil. As a result, sequestration of carbon in terrestrial ecosystems increases, in comparison to the fixed climate case, and the carbon cycle feedback to the climate system becomes negative for much of the next three centuries.
Download or read book Carbon and Nitrogen in the Terrestrial Environment written by R. Nieder and published by Springer Science & Business Media. This book was released on 2008-05-30 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon and Nitrogen in the Terrestrial Environment is a comprehensive, interdisciplinary description of C and N fluxes between the atmosphere and the terrestrial biosphere; issues related to C and N management in different ecosystems and their implications for the environment and global climate change; and the approaches to mitigate emission of greenhouse gases. Drawing upon the most up-to-date books, journals, bulletins, reports, symposia proceedings and internet sources documenting interrelationships between different aspects of C and N cycling in the terrestrial environment, Carbon and Nitrogen in the Terrestrial Environment fills the gap left by most of the currently available books on C and N cycling. They either deal with a single element of an ecosystem, or are related to one or a few selected aspects like soil organic matter (SOM) and agricultural or forest management, emission of greenhouse gases, global climate change or modeling of SOM dynamics.
Download or read book Human Interactions with the Carbon Cycle written by National Research Council and published by National Academies Press. This book was released on 2002-04-29 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: The USGCRP's Carbon Cycle Working Group asked the National Research Council's Committee on the Human Dimensions of Global Change to hold a workshop on Human Interactions with the Carbon Cycle. The basic purpose of the workshop was to help build bridges between the research communities in the social sciences and the natural sciences that might eventually work together to produce the needed understanding of the carbon cycle-an understanding that can inform public decisions that could, among other things, prevent disasters from resulting from the ways humanity has been altering the carbon cycle. Members of the working group hoped that a successful workshop would improve communication between the relevant research communities in the natural and social sciences, leading eventually to an expansion of the carbon cycle program element in directions that would better integrate the two domains.
Download or read book Importance of Carbon nitrogen Interactions and Ozone on Ecosystem Hydrology During the 21st Century written by Benjamin Seth Felzer and published by . This book was released on 2009 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of various aspects of global change (e.g., climate change, changes in the chemistry of the atmosphere, such as CO2 and O3, and land-use change) on the hydrologic cycle are becoming an important research area. For example, with respect to increases in atmospheric CO2, recent work supports the contention that there will be reduced evapotranspiration and therefore increased water availability in a CO2-rich world. Our new research on this topic suggests that various aspects of global change combine to affect hydrology in terrestrial ecosystems, and that it is particularly important to include carbon-nitrogen interactions in these studies. We have developed a new version of the Terrestrial Ecosystems Model (TEM) to examine the effects of carbon-nitrogen interactions on the water cycle. This new version includes explicit modeling of the stomatal exchange of CO2 and water, as well as a new approach to carbon and nitrogen allocation in plants. Using this new version of TEM, we have performed a range of site-level and regional experiments across the eastern United States. For example, using data from Harvard Forest, MA, a predominantly deciduous mixed forest, we ran two transient simulations from 1700 to 2100, with and without considering nitrogen limitations on plant productivity. In both of these simulations, we allowed CO2 to double by 2100, but maintained present-day climate. In these two experiments, we found that runoff increased through the 21st century in response to elevated atmospheric CO2. Without nitrogen limitation on plant productivity, the increase in runoff was 12%. However, with nitrogen limitation on plant productivity, the increase in runoff nearly doubled to 21%. This difference in runoff response was the result of a stronger transpiration reduction associated with a smaller increase in photosynthesis in the nitrogen limitation case. In this resentation we will discuss a set of site-level and regional experiments that explore the effects of carbon-nitrogen interactions on the water cycle in the context of different combinations of global changes including climate changes, changes in nitrogen deposition, and changes in tropospheric ozone. Since the carbon and water cycles are tightly coupled, future considerations of ecohydrology must take into account carbon-nitrogen interactions and other multiple stresses that strongly influence the carbon cycle.
Download or read book Impacts of Climate Change on Carbon and Nitrogen Cycles in Boreal Forest Ecosystems written by Peter Eliasson and published by . This book was released on 2007 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulations of increased CO2 also confirmed positive growth response in the short term. The response of soil carbon was similar, however predicted to be less than the increase of biomass. Nitrogen availability and negative feedback mechanisms of the plant soil system were critical to the results, indicating that nitrogen progressively limited the growth response.
Download or read book Carbon Cycle Research and Agriculture s Role in Reducing Climate Change written by United States. Congress. Senate. Committee on Agriculture, Nutrition, and Forestry. Subcommittee on Research, Nutrition, and General Legislation and published by . This book was released on 2001 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Examining the Role of Climate Carbon and Nitrogen Interactions in the Terrestrial Biosphere written by Xiaojuan Yang and published by ProQuest. This book was released on 2009 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is compelling evidence showing that terrestrial biosphere has acted as a net carbon (C) sink in recent decades. However there is large uncertainty regarding the magnitude and location of the C sink predominantly due to large uncertainties associated with C emissions from land use change and C sinks due to other processes such as the CO2 fertilization effect, the effect of climate change and the effect of nitrogen (N) deposition. This thesis focuses on understanding and assessing the interactions between the C cycle, N cycle and climate and how they might impact terrestrial C sources and sinks in the context of increasing atmospheric CO2 concentrations ([CO 2]), climate change, N deposition and land use change by using a global terrestrial C-N cycle model in the modeling framework of the Integrated Science Assessment Model (ISAM).
Download or read book Direct and Indirect Human Contributions to Terrestrial Carbon Fluxes written by National Research Council and published by National Academies Press. This book was released on 2004-06-30 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Human-induced climate change is an important environmental issue worldwide, as scientific studies increasingly demonstrate that human activities are changing the Earth's climate. Even if dramatic reductions in emissions were made today, some human-induced changes are likely to persist beyond the 21st century. The Kyoto Protocol calls for emissions reporting that separates out management-induced changes in greenhouse gases from those changes caused by indirect human effects (e.g., carbon dioxide fertilization, nitrogen deposition, or precipitation changes), natural effects, and past practices on forested agricultural lands. This book summarizes a September 2003 workshop where leaders from academia, government and industry came together to discuss the current state of scientific understanding on quantifying direct human-induced change in terrestrial carbon stocks and related changes in greenhouse gas emissions and distinguishing these changes from those caused by indirect and natural effects.
Download or read book Carbon Cycles and Climate written by Jerry S. Olson and published by . This book was released on 1980 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This partially annotated bibliography contains the first 1000 references from a computerized file of literature on the global ecological implications of carbon cycles and climatic changes. Many early citations originated from the Biogeochemical Ecological Information Center established at Oak Ridge National Laboratory in 1968 and from profiles of computerized files such as Government Research Abstracts (GRA) and Biological Abstracts (BA). Later citations have been extracted from the open literature through 1978 and early 1979, from government reports and impact statements, and from profiles of GRA, BA, and the Energy Data Base of the Department of Energy Technical Information Center, Oak Ridge, Tennessee. The subject categories covered by this bibliography may be divided into two main topics: carbon cycling and climate system analysis. Volume I contains an introduction and overview. Volume 2 contains an alphabetical (by author) listing of citations. Volume 3 provides indexes for author, organization (corporate authority), keywords (or free index terms), taxonomic category, subject category, Chemical Abstracts codes, Biological Abstracts codes (crosscode), and COSATI/Weekly Government Abstracts codes concentrated with permuted title words.
Download or read book Carbon Nitrogen Sulfur written by V. Smil and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: ica, I considered myself an old hand: when I started to study the environment of the North Bohemian region in 1963, the ecosystemic changes and health effects result ing from extremely high concentrations and deposition of sulfurous and nitrogenous air pollutants and particulate matter could not be ignored. When I returned to the area in 1966 to work there for nearly three years as a consultant in energy and environmental affairs, I came to realize the difficulties of efficiently controlling the problem. Hiking on the crest of the Ore Mountains overlooking the valley, I saw much destruction and degradation of coniferous plantings-but I was also repeatedly surprised by the contrast of the withering tops and stunted dried-out growth of spruces and firs with the magnificent beech trees and the healthy understory of shrubs and wild flowers. I recall this impressive lesson of ecosystemic vulnerability and resistance every time I read sweeping generalizations about the environmental effects of acid deposition. At the same time, in the second half of the 1960s, I was introduced by a friend, an engineer working in analytical chemistry and biochemistry, to some of the mysteries of enzymes; this led me to nitrogenase, one of the most incredible sub stances on this planet, and to an interest in various aspects of the nitrogen cycle, which was further strengthened by my later work on the energy cost of crop production, involving inevitable comparisons between natural nitrogen fixation and Haber-Bosch ammonia synthesis.
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 Global Implications of the Nitrogen Cycle written by Trelita de Sousa and published by Cambridge Scholars Publishing. This book was released on 2020-07-16 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrogen constitutes 78% of the Earth’s atmosphere and inevitably occupies a predominant role in marine and terrestrial nutrient biogeochemistry and the global climate. Callous human activities, like the excessive industrial nitrogen fixation and the incessant burning of fossil fuels, have caused a massive acceleration of the nitrogen cycle, which has, in turn, led to an increasing trend in eutrophication, smog formation, acid rain, and emission of nitrous oxide, which is a potent greenhouse gas, 300 times more powerful in warming the Earth’s atmosphere than carbon dioxide. This book comprehensively reviews the biotransformation of nitrogen, its ecological significance and the consequences of human interference. It will appeal to environmentalists, ecologists, marine biologists, and microbiologists worldwide, and will serve as a valuable guide to graduates, post-graduates, research scholars, scientists, and professors.
Download or read book The Role of Carbon nitrogen Interactions for Terrestrial Ecosystem Dynamics Under Global Change written by and published by . This book was released on 2013 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Variability of Terrestrial Carbon Cycle and Its Interaction with Climate Under Global Warming written by Haifeng Qian and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantification and Reduction of Uncertainties Associated with Carbon Cycle climate System Feedbacks written by Forrest McCoy Hoffman and published by . This book was released on 2015 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic perturbation of global biogeochemical cycles, particularly through emissions of radiatively active greenhouse gases into the atmosphere-chiefly carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)--is altering the Earth's climate and inducing feedbacks from the terrestrial biosphere and oceans on future CO2 levels and the climate system. Identifying and quantifying these feedbacks and quantifying and reducing uncertainties associated with them in process-rich Earth system models (ESMs) are important for advancing our understanding of the Earth system, predicting future atmospheric CO2 levels, informing carbon management and energy policies, and fostering the future of life on Earth. This dissertation presents three studies designed to advance our understanding of biogeochemical processes and their interactions with climate under conditions of increasing atmospheric CO2 and to offer an approach for understanding observational representativeness and for scaling up measurements. In the first investigation, I analyzed emission-driven simulations of ESMs from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) in which atmospheric CO2 levels were computed prognostically. Comparison of ESM prognostic atmospheric CO2 over the historical period with observations indicated that ESMs, on average, had a small positive bias in predictions of contemporary atmospheric CO2, due in part to weak ocean carbon uptake. I found a significant linear relationship between contemporary atmospheric CO2 biases and future CO2 levels for the multimodel ensemble, and used this emergent constraint to create a contemporary CO2 tuned model (CCTM) to estimate an atmospheric CO2 trajectory for the 21st century for the Representative Concentration Pathway (RCP) 8.5. The CCTM yielded CO2 estimates of 600 +̲ 14 ppm at 2060 and 947 +̲ 35 ppm at 2100, which were 21 ppm and 32 ppm below the multi-model mean during these two time periods, respectively. This analysis indicated that much of the model-to-model variation in projected CO2 during the 21st century was tied to biases that existed during the observational era and that model differences in the representation of concentration0́3carbon feedbacks and other slowly varying carbon cycle processes appear to be the primary driver of this variability. In the second study, I extended a quantitative methodology for stratifying sampling domains and understanding the representativeness of measurements, measurement sites, and observational networks. Multivariate spatiotemporal clustering was applied to down-scaled general circulation model results and data for the State of Alaska at 4 km2 resolution to define multiple sets of ecoregions across two decadal time periods and to identify optimal sampling locations for those ecoregions. I developed a representativeness metric and used it to characterize environmental dissimilarity between potential sampling sites. This analysis provided insights into optimal sampling strategies and offered a framework for up-scaling measurements that can be applied at different spatial and temporal scales to meet the needs of individual measurement campaigns. In the third investigation, I applied a feedback analysis framework to three sets of long-term climate change simulations from the Community Earth System Model version 1.0 (CESM1(BGC)) to quantify drivers of nonlinear terrestrial and ocean responses of carbon uptake. In the biogeochemically coupled simulation (BGC), the effects of CO2 fertilization and nitrogen deposition were expressed in the biosphere. In the radiatively coupled simulation (RAD), the effects of rising temperature and circulation changes due to radiative forcing from CO2, other greenhouse gases, and aerosols were expressed in the atmosphere. In the third, fully coupled simulation (FC), both the bigoeochemical and radiative coupling effects acted simultaneously. I found that climate0́3carbon sensitivities derived from RAD simulations produced a net ocean carbon storage climate sensitivity that is weaker and a net land carbon storage climate sensitivity that is stronger than those diagnosed from the FC and BGC simulations. For the ocean, this nonlinearity was associated with warming-induced weakening of ocean circulation and mixing that limited exchange of dissolved inorganic carbon between surface and deeper water masses. For the land, this nonlinearity was associated with strong gains in vegetation productivity in the FC simulation that were driven by enhancements in the hydrological cycle and increased nutrient availability. I developed and applied a nonlinearity metric for individual model variables to rank nonlinear responses and drivers. For these simulations, the overall climate0́3carbon cycle feedback gain at 2300 was 28% lower when estimated from climate0́3carbon sensitivities derived from the RAD simulation than when derived from the difference between the FC and BGC simulations. The gain estimated from compatible emissions calculations corresponded well with the gain estimated from FC ? BGC climate--carbon sensitivity parameters, confirming the validity of the larger gain. This difference has direct implications for carbon management and energy policies because underestimating the climate--carbon cycle feedback gain would result in allowable emissions estimates that would be too low to meet climate change targets. In these studies, I have shown that 1) we can reduce uncertainties in future climate projections by improving models to more closely match the long-term time series of observed atmospheric CO2; 2) we can reduce sampling biases and partition important environmental gradients to design an optimized network of sampling sites at desired scales; and 3) we can reduce uncertainties in the assessment of climate--carbon cycle feedbacks due to nonlinear terrestrial and marine responses by deriving climate--carbon sensitivities from fully coupled and biogeochemically coupled simulations.
Download or read book The Carbon Cycle written by Peter Folger and published by . This book was released on 2007 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon is stored in the atmosphere, in the oceans, in vegetation, and in soils on the land surface. Huge quantities of carbon are actively exchanged between the atmosphere and the other storage pools of carbon. The exchange, or flux, of carbon between the atmosphere, oceans, and land surface is called the carbon cycle. In sheer magnitude, human activities contribute a relatively small amount of carbon, primarily as carbon dioxide (CO2), to the global carbon cycle. Burning fossil fuels, for example, adds less than 5% to the total amount of CO2 released from the oceans and land surface to the atmosphere each year. If humans add only a small amount of CO2 to the atmosphere each year, why is that contribution important to global climate change? In short, the oceans, vegetation, and soils cannot consume carbon released from human activities quickly enough to stop CO2 from accumulating in the atmosphere. Humans tap the huge pool of fossil carbon for energy, and affect the global carbon cycle by transferring fossil carbon -- which took millions of years to accumulate -- into the atmosphere over a relatively short time span. As a result, the atmosphere contains 100 parts per million more today (380 ppm vs 280 ppm) than prior to the beginning of the industrial revolution. As the CO2 concentration grows it increases the radiative forcing (more incoming radiation energy than outgoing) of the atmosphere, warming the planet. In response, Congress is considering legislative strategies that would reduce U.S. emissions of CO2, or increase the uptake of CO2 from the atmosphere, or both. Less than half of the total amount of CO2 released from burning fossil fuels during the past 250 years has remained in the atmosphere because two huge reservoirs for carbon -- the global oceans and the land surface -- take up more carbon than they release. They are net sinks for carbon. If the oceans, vegetation, and soils did not accumulate as much carbon as they do today, then the concentration of CO2 in the atmosphere would increase even more rapidly. A key issue to consider is whether these two sinks will continue to store carbon at the same rate over the next few decades. Will the sinks remove more, less, or the same amount of CO2 released from fossil fuel combustion each year? Currently, most of the total global carbon sink is referred to as the unmanaged, or background, carbon cycle. Very little carbon is removed from the atmosphere and stored, or sequestered, by deliberate action. Congress may opt to consider how land management practices, such as afforestation, conservation tillage, and other techniques, might increase the net flux of carbon from the atmosphere to the land surface. How the ocean sink could be managed to store more carbon is unclear. Iron fertilization and deep ocean injection of CO2 are in an experimental stage, and their promise for long-term enhancement of carbon uptake by the oceans is not well understood. Congress may consider incorporating what is known about the carbon cycle into its legislative strategies, and may also evaluate whether the global carbon cycle is sufficiently well understood so that the consequences of long-term policies aimed at mitigating global climate change are fully appreciated.
Download or read book Handbook Of Climate Change And Agroecosystems Impacts Adaptation And Mitigation written by Daniel Hillel and published by World Scientific. This book was released on 2010-09-03 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: The portending process of climate change, induced by the anthropogenic accumulations of greenhouse gases in the atmosphere, is likely to generate effects that will cascade through the biosphere, impacting all life on earth and bearing upon human endeavors. Of special concern is the potential effect on agriculture and global food security.Anticipating these effects demands that scientists widen their field of vision and cooperate across disciplines to encompass increasingly complex interactions. Trans-disciplinary cooperation should aim to generate effective responses to the evolving risks, including actions to mitigate the emissions of greenhouse gases and to adapt to those climate changes that cannot be avoided.This handbook presents an exposition of current research on the impacts, adaptation, and mitigation of climate change in relation to agroecosystems. It is offered as the first volume in what is intended to be an ongoing series dedicated to elucidating the interactions of climate change with a broad range of sectors and systems, and to developing and spurring effective responses to this global challenge. As the collective scientific and practical knowledge of the processes and responses involved continues to grow, future volumes in the series will address important aspects of the topic periodically over the coming years.
