scholarly journals Constraints on Earth System Functioning at the Paleocene‐Eocene Thermal Maximum From the Marine Silicon Cycle

2020 ◽  
Vol 35 (5) ◽  
Author(s):  
Guillaume Fontorbe ◽  
Patrick J. Frings ◽  
Christina L. De La Rocha ◽  
Katharine R. Hendry ◽  
Daniel J. Conley
Keyword(s):  
Earth System ◽  
Silicon Cycle ◽  
Thermal Maximum ◽  
System Functioning

scholarly journals Constraints on the onset duration of the Paleocene–Eocene Thermal Maximum

2018 ◽  
Vol 376 (2130) ◽  
pp. 20170082 ◽  
Author(s):  
Sandra Kirtland Turner
Keyword(s):  
System Model ◽  
Test Case ◽  
Earth System ◽  
Carbon Cycle Model ◽  
The Earth ◽  
Carbon Isotope Excursion ◽  
Geological Past ◽  
Thermal Maximum ◽  
Age Model ◽  
Volcanic Outgassing

The Paleocene–Eocene Thermal Maximum (PETM, approx. 56 Ma) provides a test case for investigating how the Earth system responds to rapid greenhouse gas-driven warming. However, current rates of carbon emissions are approximately 10 Pg C yr −1 , whereas those proposed for the PETM span orders of magnitude—from ≪1 Pg C yr −1 to greater than the anthropogenic rate. Emissions rate estimates for the PETM are hampered by uncertainty over the total mass of PETM carbon released as well as the PETM onset duration. Here, I review constraints on the onset duration of the carbon isotope excursion (CIE) that is characteristic of the event with a focus on carbon cycle model-based attempts that forgo the need for a traditional sedimentary age model. I also review and compare existing PETM carbon input scenarios employing the Earth system model cGENIE and suggest another possibility—that abrupt input of an isotopically depleted carbon source combined with elevated volcanic outgassing over a longer interval can together account for key features of the PETM CIE. This article is part of a discussion meeting issue ‘Hyperthermals: rapid and extreme global warming in our geological past’.

scholarly journals Dynamics of sediment flux to a bathyal continental margin section through the Paleocene–Eocene Thermal Maximum

2018 ◽  
Vol 14 (7) ◽  
pp. 1035-1049 ◽  
Author(s):  
Tom Dunkley Jones ◽  
Hayley R. Manners ◽  
Murray Hoggett ◽  
Sandra Kirtland Turner ◽  
Thomas Westerhold ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Isotope ◽  
Continental Margin ◽  
The Body ◽  
Sediment Flux ◽  
Stratigraphic Correlation ◽  
Earth System ◽  
Accumulation Rates ◽  
Thermal Maximum ◽  
Organic Carbon Burial

Abstract. The response of the Earth system to greenhouse-gas-driven warming is of critical importance for the future trajectory of our planetary environment. Hyperthermal events – past climate transients with global-scale warming significantly above background climate variability – can provide insights into the nature and magnitude of these responses. The largest hyperthermal of the Cenozoic was the Paleocene–Eocene Thermal Maximum (PETM ∼ 56 Ma). Here we present new high-resolution bulk sediment stable isotope and major element data for the classic PETM section at Zumaia, Spain. With these data we provide a new detailed stratigraphic correlation to other key deep-ocean and terrestrial PETM reference sections. With this new correlation and age model we are able to demonstrate that detrital sediment accumulation rates within the Zumaia continental margin section increased more than 4-fold during the PETM, representing a radical change in regional hydrology that drove dramatic increases in terrestrial-to-marine sediment flux. Most remarkable is that detrital accumulation rates remain high throughout the body of the PETM, and even reach peak values during the recovery phase of the characteristic PETM carbon isotope excursion (CIE). Using a series of Earth system model inversions, driven by the new Zumaia carbon isotope record, we demonstrate that the silicate weathering feedback alone is insufficient to recover the PETM CIE, and that active organic carbon burial is required to match the observed dynamics of the CIE. Further, we demonstrate that the period of maximum organic carbon sequestration coincides with the peak in detrital accumulation rates observed at Zumaia. Based on these results, we hypothesise that orbital-scale variations in subtropical hydro-climates, and their subsequent impact on sediment dynamics, may contribute to the rapid climate and CIE recovery from peak-PETM conditions.

scholarly journals Long-term legacy of massive carbon input to the Earth system: Anthropocene versus Eocene

2013 ◽  
Vol 371 (2001) ◽  
pp. 20120006 ◽  
Author(s):  
Richard E. Zeebe ◽  
James C. Zachos
Keyword(s):  
Mass Extinctions ◽  
Earth System ◽  
Natural Processes ◽  
Surface Ocean ◽  
The Earth ◽  
Biotic Diversity ◽  
Thermal Maximum ◽  
Recovery Times ◽  
Carbon Release

Over the next few centuries, with unabated emissions of anthropogenic carbon dioxide (CO 2 ), a total of 5000 Pg C may enter the atmosphere, causing CO 2 concentrations to rise to approximately 2000 ppmv, global temperature to warm by more than 8 ° C and surface ocean pH to decline by approximately 0.7 units. A carbon release of this magnitude is unprecedented during the past 56 million years—and the outcome accordingly difficult to predict. In this regard, the geological record may provide foresight to how the Earth system will respond in the future. Here, we discuss the long-term legacy of massive carbon release into the Earth's surface reservoirs, comparing the Anthropocene with a past analogue, the Palaeocene–Eocene Thermal Maximum (PETM, approx. 56 Ma). We examine the natural processes and time scales of CO 2 neutralization that determine the atmospheric lifetime of CO 2 in response to carbon release. We compare the duration of carbon release during the Anthropocene versus PETM and the ensuing effects on ocean acidification and marine calcifying organisms. We also discuss the conundrum that the observed duration of the PETM appears to be much longer than predicted by models that use first-order assumptions. Finally, we comment on past and future mass extinctions and recovery times of biotic diversity.

scholarly journals Megaherbivore impacts on ecosystem and Earth system functioning: the current state of the science

Ecography ◽  
2021 ◽  
Author(s):  
Olli Hyvarinen ◽  
Mariska Te Beest ◽  
Elizabeth le Roux ◽  
Graham Kerley ◽  
Esther de Groot ◽  
...  
Keyword(s):  
Earth System ◽  
Current State ◽  
System Functioning ◽  
State Of The Science

Towards a green water planetary boundary

2021 ◽  
Author(s):  
Lan Wang-Erlandsson ◽  
Ruud van der Ent ◽  
Arie Staal ◽  
Miina Porkka ◽  
Arne Tobian ◽  
...  
Keyword(s):  
Evaluation Criteria ◽  
Expert Elicitation ◽  
Water Dynamics ◽  
Green Water ◽  
Earth System ◽  
Planetary Scale ◽  
The Earth ◽  
Spatially Distributed ◽  
System Functioning ◽  
Operating Space

<p>Green water - soil moisture, evaporation, and precipitation over land - is fundamental to safeguard Earth system functioning. Nonlinear green-water driven changes in climate, ecosystems, biogeochemistry, and hydrology are becoming increasingly evident and widespread. Yet, considerations of continental to planetary scale green-water dynamics are yet to be assessed and incorporated in management and governance. Here, we propose a green water planetary boundary (PB) - as part of the planetary boundary framework that demarcates a global “safe-operating space” for humanity - for assessing green-water related changes that can affect the capacity of the Earth system to remain in Holocene-like conditions. We consider green-water related processes associated with all scales: spatially distributed units, regions or biomes, and the Earth system as a whole. The proposed green water PB variable is selected through expert elicitation based on a set of transparent evaluation criteria that consider both scientific and governability aspects. Finally, we clarify the appropriate use of a green water PB, outline remaining challenges, and propose a research agenda for future navigation and quantitative assessments of the biophysical Earth system scale boundaries of green water changes.</p>

Non-equilibrium thermodynamics, maximum entropy production and Earth-system evolution

2010 ◽  
Vol 368 (1910) ◽  
pp. 181-196 ◽  
Author(s):  
Axel Kleidon
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Thermodynamic Equilibrium ◽  
Earth System ◽  
Equilibrium Thermodynamic ◽  
Equilibrium Thermodynamics ◽  
System Evolution ◽  
The Earth ◽  
System Functioning ◽  
Non Equilibrium

The present-day atmosphere is in a unique state far from thermodynamic equilibrium. This uniqueness is for instance reflected in the high concentration of molecular oxygen and the low relative humidity in the atmosphere. Given that the concentration of atmospheric oxygen has likely increased throughout Earth-system history, we can ask whether this trend can be generalized to a trend of Earth-system evolution that is directed away from thermodynamic equilibrium, why we would expect such a trend to take place and what it would imply for Earth-system evolution as a whole. The justification for such a trend could be found in the proposed general principle of maximum entropy production (MEP), which states that non-equilibrium thermodynamic systems maintain steady states at which entropy production is maximized. Here, I justify and demonstrate this application of MEP to the Earth at the planetary scale. I first describe the non-equilibrium thermodynamic nature of Earth-system processes and distinguish processes that drive the system’s state away from equilibrium from those that are directed towards equilibrium. I formulate the interactions among these processes from a thermodynamic perspective and then connect them to a holistic view of the planetary thermodynamic state of the Earth system. In conclusion, non-equilibrium thermodynamics and MEP have the potential to provide a simple and holistic theory of Earth-system functioning. This theory can be used to derive overall evolutionary trends of the Earth’s past, identify the role that life plays in driving thermodynamic states far from equilibrium, identify habitability in other planetary environments and evaluate human impacts on Earth-system functioning.

An integrated research infrastructure concept with multidisciplinary observations on climate change

2020 ◽  
Author(s):  
Jaana Bäck ◽  
Tuukka Petäjä ◽  
Mari Pihlatie ◽  
Janne Levula ◽  
Timo Vesala ◽  
...  
Keyword(s):  
Climate Change ◽  
Research Infrastructure ◽  
Ecosystem Structure ◽  
Earth System ◽  
Process Understanding ◽  
Integrated Research ◽  
System Functioning ◽  
Temperature Records ◽  
Statistical Relationships ◽  
Atmospheric Concentrations

<p>The observations on global warming or elements relevant to climate change are frequently performed in isolation, which results in insufficient understanding of the whole Earth system functioning and feedbacks. Frequently CO2 emissions, atmospheric concentrations of greenhouse gases and the global air temperature records are pooled together to obtain statistical relationships and correlations between them. However, forecasting future changes and designing tools for mitigating their deleterious effects would require a more holistic and comprehensive observation scheme. We propose a concept of an integrated research infrastructure, where the feedbacks can be analysed with multidisciplinary and comprehensive observations. The SMEAR concept (Station for Measuring Earth system-Atmosphere Relations) has been developing into a powerful tool, allowing detection of trends in key climate, atmosphere and ecosystem parameters, providing detailed process understanding of atmosphere and ecosystem structure and functions, and facilitating deep insights on feedbacks between the ecosystems and atmosphere. The presentation gives examples of recent novel results, especially in the perspective of climate change feedbacks and mitigation in forest ecosystems.</p>

scholarly journals Orbital forcing of terrestrial hydrology, weathering and carbon sequestration during the Palaeocene-Eocene Thermal Maximum

2017 ◽  
Author(s):  
Tom Dunkley Jones ◽  
Hayley R. Manners ◽  
Murray Hoggett ◽  
Sandra Kirtland Turner ◽  
Thomas Westerhold ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Radical Change ◽  
Transport Processes ◽  
The Body ◽  
Sediment Flux ◽  
Earth System ◽  
Accumulation Rates ◽  
Thermal Maximum ◽  
Organic Carbon Burial

Abstract. The response of the Earth System to greenhouse-gas driven warming is of critical importance for the future trajectory of our planetary environment. Hypethermal events – past climate transients with significant global-scale warming – can provide insights into the nature and magnitude of these responses. The largest hyperthermal of the Cenozoic was the Palaeocene-Eocene Thermal Maximum (PETM ~ 56 Ma). Here we present a new high-resolution cyclostratigraphy for the classic PETM section at Zumaia, Spain. With this new age model we are able to demonstrate that detrital sediment accumulation rates within this continental margin section increased more than four-fold during the PETM, representing a radical change in regional hydrology that drove dramatic increases in terrestrial to marine sediment flux. During the body of the PETM, orbital-scale variations in bulk sediment Si/Fe ratios are evidence for the continued orbital pacing of sediment erosion and transport processes, most likely linked to precession controls on sub-tropical hydroclimates. Most remarkable is that detrital accumulation rates remain high throughout the body of the PETM, and even reach peak values during the recovery phase of the characteristic PETM carbon isotope excursion (CIE). Using a series of Earth System Model inversions, we demonstrate that the silicate weathering feedback alone is insufficient to recover the PETM CIE, and that active organic carbon burial is required to match the observed dynamics of the CIE. Further, that the period of maximum organic carbon sequestration coincides with the peak in detrital accumulation rates observed at Zumaia. Based on these results, we hypothesize that precession controls on tropical and sub-tropical hydroclimates, and the sediment dynamics associated with this variation, play a significant role in the timing of the rapid climate and CIE recovery from peak-PETM conditions.

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