scholarly journals A 23 m.y. record of low atmospheric CO2

Geology ◽  
2020 ◽  
Vol 48 (9) ◽  
pp. 888-892 ◽  
Author(s):  
Ying Cui ◽  
Brian A. Schubert ◽  
A. Hope Jahren
Keyword(s):  
Ice Cores ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
C3 Plant ◽  
Earth History ◽  
The Past ◽  
Plant Remains ◽  
Δ13c Value ◽  
History Of ◽  
Middle Pliocene

Abstract Current atmospheric CO2 concentration is known to be higher than it has been during the past ∼800 k.y. of Earth history, based on direct measurement of CO2 within ice cores. A comparison to the more ancient past is complicated by a deficit of CO2 proxies that may be applied across very long spans of geologic time. Here, we present a new CO2 record across the past 23 m.y. of Earth history based on the δ13C value of terrestrial C3 plant remains, using a method applicable to the entire ∼400 m.y. history of C3 photosynthesis on land. Across the past 23 m.y., CO2 likely ranged between ∼230 ppmv and 350 ppmv (68% confidence interval: ∼170–540 ppm). CO2 was found to be highest during the early and middle Miocene and likely below present-day levels during the middle Pliocene (84th percentile: ∼400 ppmv). These data suggest present-day CO2 (412 ppmv) exceeds the highest levels that Earth experienced at least since the Miocene, further highlighting the present-day disruption of long-established CO2 trends within Earth’s atmosphere.

The Impacts of Climate Change on Societies: What Can We Learn from the Past?

2021 ◽  
Author(s):  
Dagomar Degroot
Keyword(s):  
Climate Change ◽  
Case Studies ◽  
Public Discourse ◽  
Climate Change Policy ◽  
Ice Cores ◽  
Keynote Presentation ◽  
The Past ◽  
Change Policy ◽  
History Of ◽  
Paleoclimatic Proxy

<p>This keynote presentation introduces the sources, methods, and major findings of the History of Climate and Society (HCS), a recently-coined field that uncovers the past influences of climate change on human history. It begins by offering a brief history of the field, from the eighteenth century through the present. It then describes how HCS scholars “reconstruct” past climate changes by combining what they call the “archives of nature” – paleoclimatic proxy sources such as tree rings, ice cores, or marine sediments – with the texts, stories, and ruins that constitute the “archives of society.” Next, it explains how HCS scholars in different disciplines have used distinct statistical and qualitative methods, and distinct causal frameworks, to identify the influence of climate change in the archives of society. It explores how HCS scholars conceptualize the vulnerability and resilience of past societies by introducing some telling case studies, and explaining how those case studies have grown more complex as HCS matured as a field. It then emphasizes the enduring challenges faced by HCS scholars and how, in recent months, they have been identified and are beginning to be addressed. Finally, it describes how HCS has informed climate change policy and public discourse, before offering some key lessons that policymakers can learn from the field.</p>

scholarly journals History of desert dust deposition recorded in the Elbrus ice core

2019 ◽  
Author(s):  
Stanislav Kutuzov ◽  
Michel Legrand ◽  
Suzanne Preunkert ◽  
Patrick Ginot ◽  
Vladimir Mikhalenko ◽  
...  
Keyword(s):  
North Africa ◽  
Drought Index ◽  
Decadal Variability ◽  
Ice Core ◽  
Ice Cores ◽  
Dust Deposition ◽  
The Past ◽  
Dust Sources ◽  
Increasing Trend ◽  
History Of

Abstract. Ice cores are one of the most valuable paleo-archives. Records from the ice cores can provide information not only about the amount of dust in the atmosphere but also about dust sources and its changes in the past. A 182 m long ice core has been recovered at the western plateau of Mt. Elbrus (5115 m elevation) in 2009. This record was extended with the shallow ice core drilling in 2013. Here we present analysis of the concentrations of Ca2+, a commonly used proxy of dust, recorded in Elbrus ice core over the period 1774–2013. The calcium record reveals a quasi decadal variability with a general increasing trend. Using multiple regression analysis we found a statistically significant spatial correlation of the Elbrus Ca2+ summer concentrations and precipitation and soil moisture content in Levant region (specifically Syria and Iraq). The Ca2+ record also correlates with drought index in North Africa (r = 0.69 p 

scholarly journals 1000 year ice-core records from Berkner Island, Antarctica

2002 ◽  
Vol 35 ◽  
pp. 45-51 ◽  
Author(s):  
Robert Mulvaney ◽  
Hans Oerter ◽  
David A. Peel ◽  
Wolfgang Graf ◽  
Carol Arrowsmith ◽  
...  
Keyword(s):  
Decadal Variability ◽  
Ice Core ◽  
Ice Cores ◽  
Aerosol Deposition ◽  
Climate History ◽  
Joint Project ◽  
The Past ◽  
Annual Layer ◽  
History Of ◽  
Field Season

AbstractTwo medium-depth ice cores were retrieved from Berkner Island by a joint project between the Alfred-Wegener-Institut and the British Antarctic Survey in the 1994/95 field season. A 151m deep core from the northern dome (Reinwarthhöhe) of Berkner Island spans 700 years, while a 181 m deep core from the southern dome (Thyssenhöhe) spans approximately 1200 years. Both cores display clear seasonal cycles in electrical conductivity measurements, allowing dating by annual-layer counting and the calculation of accumulation profiles. Stable-isotope measurements (both δ18O and δD), together with the accumulation data, allow us to estimate changes in climate for most of the past millennium: the data show multi-decadal variability around a generally stable long-termmean. In addition, a full suite of major chemistry measurements is available to define the history of aerosol deposition at these sites: again, there is little evidence that the chemistry of the sites has changed over the past six centuries. Finally, we suggest that the southern dome, with an ice thickness of 950 m, is an ideal site from which to gain a climate history of the late stages of the last glacial and the deglaciation for comparison with the records from the deep Antarctic ice cores, and with other intermediate-depth cores such as Taylor Dome and Siple Dome.

The past 5000 years history of solar modulation of cosmic radiation from 10 Be and 14 C studies

1990 ◽  
Vol 330 (1615) ◽  
pp. 471-480 ◽  
Keyword(s):  
Cosmic Radiation ◽  
Ice Core ◽  
Ice Cores ◽  
Solar Modulation ◽  
Short Term ◽  
The Past ◽  
History Of ◽  
Long Term Trends ◽  
Terrestrial Biomass

10 Be is produced in a similar way as 14 C by the interaction of cosmic radiation with the nuclei in the atmosphere. Assuming that the 10 Be and 14 C variation are proportional and considering the different behaviour in the Earth system, the 10 Be concentrations in ice cores can be compared with the 14 C variations in tree rings. A high correlation is found for the short-term variations ( 14 C-Suess-wiggles). They reflect with a high probability production rate variations. More problematic is the interpretation of the long-term trends of 14 C and 10 Be. Several explanations are discussed. The reconstructed CO 2 concentrations in ice cores indicate a rather constant value (280 ± 10 p.p.m. by volume) during the past few millenia. Measurements on the ice core from Byrd Station, Antarctica, during the period 9000 to 6000 years BP indicate a decrease that might be explained by the extraction of CO 2 from the atmosphere-ocean system to build the terrestrial biomass pool during the climatic optimum.

scholarly journals The Elbrus (Caucasus, Russia) ice core record – Part 2: history of desert dust deposition

2019 ◽  
Vol 19 (22) ◽  
pp. 14133-14148 ◽  
Author(s):  
Stanislav Kutuzov ◽  
Michel Legrand ◽  
Susanne Preunkert ◽  
Patrick Ginot ◽  
Vladimir Mikhalenko ◽  
...  
Keyword(s):  
Middle East ◽  
Decadal Variability ◽  
Southern Oscillation ◽  
Ice Core ◽  
Ice Cores ◽  
Drought Indices ◽  
Dust Deposition ◽  
The Past ◽  
Ice Core Record ◽  
History Of

Abstract. Ice cores are one of the most valuable paleo-archives. Records from ice cores provide information not only about the amount of dust in the atmosphere, but also about dust sources and their changes in the past. In 2009, a 182 m long ice core was recovered from the western plateau of Mt Elbrus (5115 m a.s.l.). This record was further extended after a shallow ice core was drilled in 2013. Here we analyse Ca2+ concentrations, a commonly used proxy of dust, recorded in these Elbrus ice records over the time period of 1774–2013 CE. The Ca2+ record reveals quasi-decadal variability with a generally increasing trend. Using multiple regression analysis, we found a statistically significant spatial correlation of the Elbrus Ca2+ summer concentrations with precipitation and soil moisture content in the Levant region (specifically Syria and Iraq). The Ca2+ record also correlates with drought indices in North Africa (r=0.67, p<0.001) and Middle East regions (r=0.71, p<0.001). Dust concentrations prominently increase in the ice core over the past 200 years, confirming that the recent droughts in the Fertile Crescent (1998–2012 CE) present the most severe aridity experienced in at least the past two centuries. For the most recent 33 years recorded (1979–2012 CE), significant correlations exist between Ca2+ and Pacific circulation indices (Pacific Decadal Oscillation, Southern Oscillation Index and Niño 4), which suggests that the increased frequency of extreme El Niño and La Niña events due to a warming climate has extended their influence to the Middle East. Evidence demonstrates that the increase in Ca2+ concentration in the ice core cannot be attributed to human activities, such as coal combustion and cement production.

scholarly journals The role of the 13C isotope of the Tree Ring in Recording of Carbon Cycle Change in Atmosphere

2014 ◽  
Vol 15 (1) ◽  
pp. 15
Author(s):  
E. Ristin Pujiindiyati
Keyword(s):  
Tree Rings ◽  
Carbon Flux ◽  
Ice Cores ◽  
Atmospheric Co2 ◽  
Climatic Effects ◽  
Pollution Effects ◽  
The Past ◽  
13C Isotope ◽  
Major Factors

Some natural materials such as tree rings, rocks, sediments, ice cores, coral reefs, shell fish and micro fossil record the chemical, physical and biological changes in atmosphere that had taken place in the past. One of these changes which are recorded in tree rings is C-13 isotope. Through the measurement of ratio of 13C compared to 12C (defined as 13C value), it can be known atmospheric CO2 conditions in the past to reflect the present conditions. Present value of 13C in atmospheric CO2 is -7.5 ‰ that had decreased gradually from -6.69 in 1956. Pre-industrial 13C value in atmospheric CO2 is not available. However, the historical records of those are stored in tree rings. Starting from pre-industrial era about 1850 up to 2000, the records of 13C value in some tree rings which are spread in northern hemisphere showed decreasing value ranging from 0.60/00 to 2.30/00. Major factors contributing to variability of these 13C values are pollution effects and climatic effects. Besides those, some effects such as choice of the wood components, inner ring variability and juvenile stage of trees are also correlated to variability of 13C value. Records of 13C value from tree rings defined that atmospheric CO2 from pre-industrial era were between 240 ppm and 310 ppm then this concentration continuously increase to 340 ppm at present. Integrated biospheric carbon flux calculated for 13C records in tree rings using four models from the year of 1850 to 1975 showed an increasing value between 135 Gt and 345 Gt. Keywords : Tree rings, C-13 isotope, atmospheric CO2

Using a Tree Ring δ13C Annual Series to Reconstruct Atmospheric CO2 Concentration over the Past 300 Years

Pedosphere ◽  
2006 ◽  
Vol 16 (3) ◽  
pp. 371-379 ◽  
Author(s):  
Xing-Yun ZHAO ◽  
Jun-Long QIAN ◽  
Jian WANG ◽  
Qing-Yan HE ◽  
Zu-Liang WANG ◽  
...  
Keyword(s):  
Tree Ring ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Annual Series ◽  
The Past ◽  
Atmospheric Co2 Concentration ◽  
Past 300 Years

scholarly journals Gaseous Components in the Atmosphere and the Historic Record Revealed by Ice Cores

1985 ◽  
Vol 7 ◽  
pp. 54-59 ◽  
Author(s):  
B. Stauffer ◽  
H. Oeschger
Keyword(s):  
Special Interest ◽  
Low Temperatures ◽  
Direct Method ◽  
Ice Cores ◽  
Atmospheric Composition ◽  
Ice Formation ◽  
The Past ◽  
Last Glaciation ◽  
History Of ◽  
Historic Record

The composition of air in bubbles of ice reveals important information on the composition of the atmosphere at the time at which the ice was formed. The enclosed air has essentially an atmospheric composition if the ice formation occurred by dry sintering of snow and firn at low temperatures. The history of atmospheric CO2 concentration is of special interest due to its present increase and its climatic implications. Currently, CO2 analysis of air extracted from ice cores seems the best and most direct method of determining the natural CO2 concentration before 1950 and possible pre-industrial variations. Analyses of ice samples representing the past 40 ka show that there were significant changes in concentration of atmospheric CO2 at the end, and probably during part, of the last glaciation. δ13C measurements on CO2 extracted from ice cores can indicate possible mechanisms causing these changes in the concentration of atmospheric CO2.

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