Late Miocene Coupling of Atmospheric Carbon Dioxide and Climate

Late Miocene Coupling of Atmospheric Carbon Dioxide and Climate PDF Author: Rachel Brown
Publisher:
ISBN:
Category :
Languages : en
Pages : 43

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Late Miocene Coupling of Atmospheric Carbon Dioxide and Climate

Late Miocene Coupling of Atmospheric Carbon Dioxide and Climate PDF Author: Rachel Brown
Publisher:
ISBN:
Category :
Languages : en
Pages : 43

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Book Description


Impact of Atmospheric CO2 and Atlantic-Arctic Gateway Evolution on Miocene Climate and Ocean Circulation Changes

Impact of Atmospheric CO2 and Atlantic-Arctic Gateway Evolution on Miocene Climate and Ocean Circulation Changes PDF Author: Akil Hossain
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
The Miocene (23.03-5.33 Ma) was a time period with a warmer climate than today. During this period, changes in ocean gateways and atmospheric CO2 levels largely control ocean circulation and climate changes. However, the underlying ocean processes and dynamics are poorly understood and it remains a challenge to simulate Miocene climate key characteristics such as pronounced polar warming and a reduced meridional temperature gradient. By applying state-of-the-art fully coupled atmosphere-ocean-sea-ice model approaches Miocene climate conditions at different atmospheric CO2 concentrations are simulated and thermohaline changes in response to the subsidence of Atlantic-Arctic gateways for various Greenland-Scotland Ridge (GSR) and Fram Strait (FS) configurations are investigated. For a singular subsidence of the GSR, warming and a salinity increase in the Nordic Seas and the Arctic Ocean is detected. As convection sites shift to the north of Iceland, North Atlantic Deep Water (NADW) is formed at cooler temperatures. The associated deep ocean cooling and upwelling of deep waters to the Southern Ocean surface can cause a cooling in the southern high latitudes. These characteristic responses to the GSR deepening are independent of the FS being shallow or deep. An isolated subsidence or widening of the FS gateway for a deep GSR shows less pronounced warming and salinity increase in the Nordic Seas. Arctic temperatures remain unaltered, but a stronger salinity increase is detected, which further increases the density of NADW. The increase in salinity enhances the contribution of NADW to the abyssal ocean at the expense of the colder southern source water component. These relative changes cause a negligible warming in the upwelling regions of the Southern Ocean. For a sill depth of ~1500 m, ventilation of the Arctic Ocean is achieved due to enhanced import of saline Atlantic water through a FS width of ~105 km. Moreover, at this width and depth, a modern-like three-layer stratification in the Arctic Ocean is detected. The exchange flow through FS is characterized by vertical separation of a low salinity cold outflow from the Arctic Ocean confined to a thin upper layer, an intermediate saline inflow from the Atlantic Ocean below and a cold bottom Arctic outflow. These characteristics are comparable to the present-day hydrography, in spite of significantly shallower and narrower FS configurations during the early Miocene, suggesting that the ventilation mechanisms and stratification in the Arctic Ocean have been similar. In simulations with different CO2 levels (280, 450 and 720 ppm) surface temperatures show the best fit to proxy reconstructions for atmospheric CO2 concentrations of 720 ppm, since in particular the high latitude cooling bias becomes least pronounced. For a CO2 increase from 280 to 450 ppm polar amplification is simulated in the northern high latitudes, which is stronger than for the same radiative CO2 forcing from 450 to 720 ppm. At higher CO2 levels the Miocene climate also shows a reduced climate sensitivity, since the warmest Miocene climate scenario with a CO2 level of 720 ppm is characterized by a seasonality breakdown in the Arctic Ocean. A pronounced warming in boreal winter is detected for a CO2 increase from 450 to 720 ppm, in contrast to a moderate boreal summer temperature increase. This change in the seasonal temperature signature is accompanied by a strong sea-ice concentration decline and enhanced moisture availability promotes cloud formation in the summer months. As a consequence the planetary albedo increases and dampens the temperature response to the CO2 forcing at a warmer Miocene background climate.

Encyclopedia of Paleoclimatology and Ancient Environments

Encyclopedia of Paleoclimatology and Ancient Environments PDF Author: Vivien Gornitz
Publisher: Springer Science & Business Media
ISBN: 1402045514
Category : Science
Languages : en
Pages : 1062

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Book Description
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.

Antarctic Climate Evolution

Antarctic Climate Evolution PDF Author: Fabio Florindo
Publisher: Elsevier
ISBN: 0080931618
Category : Science
Languages : en
Pages : 606

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Book Description
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

Ice Ages and Astronomical Causes

Ice Ages and Astronomical Causes PDF Author: Richard A. Muller
Publisher: Springer Science & Business Media
ISBN: 9783540437796
Category : Science
Languages : en
Pages : 338

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Book Description
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.

Understanding Earth's Deep Past

Understanding Earth's Deep Past PDF Author: National Research Council
Publisher: National Academies Press
ISBN: 0309209196
Category : Science
Languages : en
Pages : 153

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Book Description
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.

The Carbon Cycle and Atmospheric CO2

The Carbon Cycle and Atmospheric CO2 PDF Author: Eric T. Sundquist
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 648

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Book Description


Exploring Coupled Land-Atmosphere Carbon Dynamics and Seasonal Carbon Forecast Skill

Exploring Coupled Land-Atmosphere Carbon Dynamics and Seasonal Carbon Forecast Skill PDF Author: Eungee Lee
Publisher: Nimble Books
ISBN: 9781608882908
Category : Science
Languages : en
Pages : 0

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Book Description
The carbon dioxide concentration of the atmosphere is the primary driver of greenhouse warming, which indirectly affects every human being. This illustration, likely familiar to anyone with even a casual interest in climate, shows recent trends in carbon dioxide concentrations at the reference station at Mauna Loa Observatory in Hawaii. The seasonal oscillation in concentration is apparent. Just by eyeballing the data, it is obvious that understanding the terrestrial carbon cycle's contribution to CO2 concentrations is vital to understanding climate change. Readers should want to read this document because it provides valuable insights into the impacts of regional droughts on land and atmospheric carbon, highlighting the connection between climate change and carbon dynamics. It also presents the potential for seasonal carbon forecasting, which can support decision-making in areas such as fire management, forestry, and agriculture. Additionally, the document addresses the need for improved hydrometeorological prediction and decision-making tools in vulnerable regions like the Mekong River Basin, where water availability forecasts are crucial for comprehensive basin management and addressing the impacts of climate change. This document provides information about ongoing research activities related to the terrestrial carbon cycle and its interactions with the atmosphere. The research is conducted by the Global Modeling and Assimilation Office (GMAO) of NASA and focuses on various aspects of the carbon cycle, including coupled land-atmosphere carbon dynamics, seasonal carbon forecast skill, fire carbon dynamics, and improved hydrometeorological prediction with carbon cycle processes. The document also mentions specific research projects, such as investigating the impact of regional droughts on land and atmospheric carbon, evaluating the predictability of land carbon uptake through seasonal forecasts, and developing subseasonal-to-seasonal forecasting tools for informed decision-making in the Mekong River Basin. Overall, the research aims to improve our understanding of the terrestrial carbon cycle and its role in the Earth system. This annotated edition illustrates the capabilities of the AI Lab for Book-Lovers to add context and ease-of-use to manuscripts. It includes several types of abstracts, building from simplest to more complex: TLDR (one word), ELI5, TLDR (vanilla), Scientific Style, and Action Items; essays to increase viewpoint diversity, such as Grounds for Dissent, Red Team Critique, and MAGA Perspective; and Notable Passages and Nutshell Summaries for each page.

The Carbon Cycle

The Carbon Cycle PDF Author: T. M. L. Wigley
Publisher: Cambridge University Press
ISBN: 9780521018623
Category : Science
Languages : en
Pages : 312

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Book Description
Reducing carbon dioxide (CO2) emissions is imperative to stabilizing our future climate. Our ability to reduce these emissions combined with an understanding of how much fossil-fuel-derived CO2 the oceans and plants can absorb is central to mitigating climate change. In The Carbon Cycle, leading scientists examine how atmospheric carbon dioxide concentrations have changed in the past and how this may affect the concentrations in the future. They look at the carbon budget and the "missing sink" for carbon dioxide. They offer approaches to modeling the carbon cycle, providing mathematical tools for predicting future levels of carbon dioxide. This comprehensive text incorporates findings from the recent IPCC reports. New insights, and a convergence of ideas and views across several disciplines make this book an important contribution to the global change literature.

Global Biogeochemical Cycles in the Climate System

Global Biogeochemical Cycles in the Climate System PDF Author: Ernst-Detlef Schulze
Publisher: Elsevier
ISBN: 0080507409
Category : Science
Languages : en
Pages : 373

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Book Description
The interactions of biogeochemical cycles influence and maintain our climate system. Land use and fossil fuel emissions are currently impacting the biogeochemical cycles of carbon, nitrogen and sulfur on land, in the atmosphere, and in the oceans. This edited volume brings together 27 scholarly contributions on the state of our knowledge of earth system interactions among the oceans, land, and atmosphere. A unique feature of this treatment is the focus on the paleoclimatic and paleobiotic context for investigating these complex interrelationships. * Eight-page colour insert to highlight the latest research * A unique feature of this treatment is the focus on the paleoclimatic context for investigating these complex interrelationships.