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Weathering Heights 08 July 2020 James Hansen
Weathering Heights 08 July 2020 James Hansen In 2007 Bill McKibben asked me whether 450 ppm would be a reasonable target for atmospheric CO2, if we wished to maintain a hospitable climate for future generations. 450 ppm seemed clearly too high, based on several lines of evidence, but especially based on paleoclimate data for climate change. We were just then working on a paper,1 Climate sensitivity, sea level and atmospheric carbon dioxide, 2 that included consideration of CO2 changes over the Cenozoic era, the past 65 million years, since the end of the Cretaceous era. The natural source of atmospheric CO2 is volcanic emissions that occur mainly at continental margins due to plate tectonics (“continental drift”). The natural sink is the weathering process, which ultimately deposits carbon on the ocean floor as limestone. David Beerling, an expert in trace gas biogeochemistry at the University of Sheffield, was an organizer of the meeting at which I presented the above referenced paper. Soon thereafter I enlisted David and other paleoclimate experts to help answer Bill’s question about a safe level of atmospheric CO2, which we concluded was somewhere south of 350 ppm.3 Since then, my group at Climate Science, Awareness and Solutions (CSAS), has continued to cooperate with David’s group at the University of Sheffield. One of the objectives is to investigate the potential for drawdown of atmospheric CO2 by speeding up the weathering process. In the most recent paper, which will be published in Nature tomorrow, David and co-authors report on progress in testing the potential for large-scale CO2 removal via application of rock dust on croplands. -
The Easternmost Occurrence of Mammut Pacificus (Proboscidea: Mammutidae), Based on a Partial Skull from Eastern Montana, USA
The easternmost occurrence of Mammut pacificus (Proboscidea: Mammutidae), based on a partial skull from eastern Montana, USA Andrew T. McDonald1, Amy L. Atwater2, Alton C. Dooley Jr1 and Charlotte J.H. Hohman2,3 1 Western Science Center, Hemet, CA, United States of America 2 Museum of the Rockies, Montana State University, Bozeman, MT, United States of America 3 Department of Earth Sciences, Montana State University, Bozeman, MT, United States of America ABSTRACT Mammut pacificus is a recently described species of mastodon from the Pleistocene of California and Idaho. We report the easternmost occurrence of this taxon based upon the palate with right and left M3 of an adult male from the Irvingtonian of eastern Montana. The undamaged right M3 exhibits the extreme narrowness that characterizes M. pacificus rather than M. americanum. The Montana specimen dates to an interglacial interval between pre-Illinoian and Illinoian glaciation, perhaps indicating that M. pacificus was extirpated in the region due to habitat shifts associated with glacial encroachment. Subjects Biogeography, Evolutionary Studies, Paleontology, Zoology Keywords Mammut pacificus, Mammutidae, Montana, Irvingtonian, Pleistocene INTRODUCTION Submitted 7 May 2020 The recent recognition of the Pacific mastodon (Mammut pacificus (Dooley Jr et al., 2019)) Accepted 3 September 2020 as a new species distinct from and contemporaneous with the American mastodon Published 16 November 2020 (M. americanum) revealed an unrealized complexity in North American mammutid Corresponding author evolution during the Pleistocene. Dooley Jr et al. (2019) distinguished M. pacificus from Andrew T. McDonald, [email protected] M. americanum by a suite of dental and skeletal features: (1) upper third molars (M3) Academic editor and lower third molars (m3) much narrower relative to length in M. -
Formal Ratification of the Subdivision of the Holocene Series/ Epoch
Article 1 by Mike Walker1*, Martin J. Head 2, Max Berkelhammer3, Svante Björck4, Hai Cheng5, Les Cwynar6, David Fisher7, Vasilios Gkinis8, Antony Long9, John Lowe10, Rewi Newnham11, Sune Olander Rasmussen8, and Harvey Weiss12 Formal ratification of the subdivision of the Holocene Series/ Epoch (Quaternary System/Period): two new Global Boundary Stratotype Sections and Points (GSSPs) and three new stages/ subseries 1 School of Archaeology, History and Anthropology, Trinity Saint David, University of Wales, Lampeter, Wales SA48 7EJ, UK; Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, Wales SY23 3DB, UK; *Corresponding author, E-mail: [email protected] 2 Department of Earth Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario LS2 3A1, Canada 3 Department of Earth and Environmental Sciences, University of Illinois, Chicago, Illinois 60607, USA 4 GeoBiosphere Science Centre, Quaternary Sciences, Lund University, Sölveg 12, SE-22362, Lund, Sweden 5 Institute of Global Change, Xi’an Jiaotong University, Xian, Shaanxi 710049, China; Department of Earth Sciences, University of Minne- sota, Minneapolis, MN 55455, USA 6 Department of Biology, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada 7 Department of Earth Sciences, University of Ottawa, Ottawa K1N 615, Canada 8 Centre for Ice and Climate, The Niels Bohr Institute, University of Copenhagen, Julian Maries Vej 30, DK-2100, Copenhagen, Denmark 9 Department of Geography, Durham University, Durham DH1 3LE, UK 10 -
Regional Disparity in Summer Monsoon Precipitation in the Indian Subcontinent During Northgrippian to Meghalayan Transition
REVIEW ARTICLES Regional disparity in summer monsoon precipitation in the Indian subcontinent during Northgrippian to Meghalayan transition Som Dutt1,*, Anil K. Gupta2, Rahul Devrani1, Ram R. Yadav1 and Raj K. Singh3 1Wadia Institute of Himalayan Geology, 33, General Mahadeo Singh Road, Dehradun 248 001, India 2Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721 302, India 3School of Earth, Ocean and Climate Sciences, Indian Institute of Technology Bhubaneswar, Argul 752 050, India soon domain1–6,8–15. Detailed reviews on ISM variability The present study reveals distinct spatial variability of 1,2 summer monsoon precipitation in Indian subcontinent during Holocene are available , but regional precipita- during Northgrippian to Meghalayan transition. Pro- tion disparity in Indian subcontinent during the 4.2 ka tracted dry phase lasting ~1000 yrs was observed event is not much discussed. Here, we examined availa- ~4.2 ka BP in southern and northwestern India whereas ble marine and terrestrial proxy records of ISM variabi- 200–300 yrs event occurred in northeastern parts. lity from different regions in Indian subcontinent and Strong El Niño conditions beginning ~4.3 kyr BP were northern Indian Ocean (IO) for better understandings of associated with the millennial long dryness in western precipitation variability during Northgrippian to Megha- parts but its influence was limited in the eastern layan transition. region. Cross-verified, high-resolution records from different geographic regions of India are still required to ascertain if regional differences occurred in span Domain of ISM and magnitude during Northgrippian to Meghalayan transition. ISM precipitation is pivotal for socio-economic wellbeing of 1/3rd of human population living in Indian subconti- Keywords: Indian summer monsoon, Indus civilization, nent. -
Robert A. Berner 1935–2015
Robert A. Berner 1935–2015 A Biographical Memoir by Donald E. Canfield ©2019 National Academy of Sciences. Any opinions expressed in this memoir are those of the author and do not necessarily reflect the views of the National Academy of Sciences. ROBERT ARBUCKLE BERNER November 25, 1935–January 10, 2015 Elected to the NAS, 1987 Bob Berner passed away on January 10, 2015, closing the final chapter of one of the most influential and colorful geochemists of all time. I had the pleasure of working as a Ph.D. student with Bob from 1982 to 1988, a period of particular innovation and transformation in his scientific career. In what follows, I will provide some brief recol- lections of Bob as a person and mentor, while taking full account of his contributions to science. The reader is also directed to Bob’s excellent autobiography (Berner 2013 ). Bob as a Person Bob Berner, walking down the hall, his grey turtle neck half untucked at the back, with a big toothy grin; that’s the way I will remember him. Especially the grin. Bob was, of By Donald E. Canfield course, a scientific legend. We’ll get to that in a moment. But, he was also very much more than that. Bob was fun, and he loved a party. He also loved a good meal and good glass of wine. Bob was a decided Francophile and learned the basics of the French language. He had a favorite Parisian café where he knew the chef personally, and they knew Bob’s favorite meal and wine. -
Sedimentological-Geochemical Data Based Reconstruction of Climate
quaternary Article Sedimentological-Geochemical Data Based Reconstruction of Climate Changes and Human Impacts from the Peat Sequence of Round Lake in the Western Foothill Area of the Eastern Carpathians, Romania Réka Orsolya Tapody 1,Pál Sümegi 1,*, Dávid Molnár 1 ,Máté Karlik 2,3, Tünde Tör˝ocsik 1,Péter Cseh 1 and László Makó 1 1 Department of Geology and Palaeontology, University of Szeged, Egyetem Str. 2-6, H-6722 Szeged, Hungary; [email protected] (R.O.T.); [email protected] (D.M.); [email protected] (T.T.); [email protected] (P.C.); [email protected] (L.M.) 2 Isotope Climatology and Environmental Research Centre, Institute for Nuclear Research, Bem Square 18/c, H-4026 Debrecen, Hungary; [email protected] 3 Institute for Geological and Geochemical Research, RCAES, Budaörsi Str. 45, H-1112 Budapest, Hungary * Correspondence: [email protected] Abstract: This paper presents the results of comparative sedimentological and geochemical analysis of the mire at Sânpaul, Round Lake (Kerek-tó). The palaeoecological site is situated in the western Citation: Tapody, R.O.; Sümegi, P.; foothill area of the Eastern Carpathians in Romania. The primary objective of this study was to Molnár, D.; Karlik, M.; Tör˝ocsik,T.; analyse the accumulation of major and trace elements in a 7500 year-long peat and lake deposition. Cseh, P.; Makó, L. The concentrations of 13 elements were determined by using handheld XRF. This paper presents Sedimentological-Geochemical Data the results of a multidisciplinary study, for which the principal aims were to examine the long- Based Reconstruction of Climate term relationship between land degradation in the Homoród Hills using various palaeoecological Changes and Human Impacts from techniques, primarily comparative geochemical analyses. -
International Chronostratigraphic Chart
INTERNATIONAL CHRONOSTRATIGRAPHIC CHART www.stratigraphy.org International Commission on Stratigraphy v 2018/08 numerical numerical numerical Eonothem numerical Series / Epoch Stage / Age Series / Epoch Stage / Age Series / Epoch Stage / Age GSSP GSSP GSSP GSSP EonothemErathem / Eon System / Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) / Eon Erathem / Era System / Period GSSA age (Ma) present ~ 145.0 358.9 ± 0.4 541.0 ±1.0 U/L Meghalayan 0.0042 Holocene M Northgrippian 0.0082 Tithonian Ediacaran L/E Greenlandian 152.1 ±0.9 ~ 635 Upper 0.0117 Famennian Neo- 0.126 Upper Kimmeridgian Cryogenian Middle 157.3 ±1.0 Upper proterozoic ~ 720 Pleistocene 0.781 372.2 ±1.6 Calabrian Oxfordian Tonian 1.80 163.5 ±1.0 Frasnian Callovian 1000 Quaternary Gelasian 166.1 ±1.2 2.58 Bathonian 382.7 ±1.6 Stenian Middle 168.3 ±1.3 Piacenzian Bajocian 170.3 ±1.4 Givetian 1200 Pliocene 3.600 Middle 387.7 ±0.8 Meso- Zanclean Aalenian proterozoic Ectasian 5.333 174.1 ±1.0 Eifelian 1400 Messinian Jurassic 393.3 ±1.2 7.246 Toarcian Devonian Calymmian Tortonian 182.7 ±0.7 Emsian 1600 11.63 Pliensbachian Statherian Lower 407.6 ±2.6 Serravallian 13.82 190.8 ±1.0 Lower 1800 Miocene Pragian 410.8 ±2.8 Proterozoic Neogene Sinemurian Langhian 15.97 Orosirian 199.3 ±0.3 Lochkovian Paleo- 2050 Burdigalian Hettangian 201.3 ±0.2 419.2 ±3.2 proterozoic 20.44 Mesozoic Rhaetian Pridoli Rhyacian Aquitanian 423.0 ±2.3 23.03 ~ 208.5 Ludfordian 2300 Cenozoic Chattian Ludlow 425.6 ±0.9 Siderian 27.82 Gorstian -
Target Atmospheric CO2: Where Should Humanity Aim?
Target Atmospheric CO2: Where Should Humanity Aim? James Hansen,1,2* Makiko Sato,1,2 Pushker Kharecha,1,2 David Beerling,3 Valerie Masson-Delmotte,4 Mark Pagani,5 Maureen Raymo,6 Dana L. Royer,7 James C. Zachos8 Paleoclimate data show that climate sensitivity is ~3°C for doubled CO2, including only fast feedback processes. Equilibrium sensitivity, including slower surface albedo feedbacks, is ~6°C for doubled CO2 for the range of climate states between glacial conditions and ice- free Antarctica. Decreasing CO2 was the main cause of a cooling trend that began 50 million years ago, large scale glaciation occurring when CO2 fell to 425±75 ppm, a level that will be exceeded within decades, barring prompt policy changes. If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm. The largest uncertainty in the target arises from possible changes of non-CO2 forcings. An initial 350 ppm CO2 target may be achievable by phasing out coal use except where CO2 is captured and adopting agricultural and forestry practices that sequester carbon. If the present overshoot of this target CO2 is not brief, there is a possibility of seeding irreversible catastrophic effects. Human activities are altering Earth’s atmospheric composition. Concern about global warming due to long-lived human-made greenhouse gases (GHGs) led to the United Nations Framework Convention on Climate Change (1) with the objective of stabilizing GHGs in the atmosphere at a level preventing “dangerous anthropogenic interference with the climate system.” The Intergovernmental Panel on Climate Change (IPCC, 2) and others (3) used several “reasons for concern” to estimate that global warming of more than 2-3°C may be dangerous. -
Statement on Chibanian Sw
1st July, 2018 Statement Regarding the Chibanian The Geological Society of Japan President Hiroki Matsuda In June last year, a research group consisting of 32 Japanese scientists from 22 institutes submitted a proposal to the International Union of Geological Sciences (IUGS) for the Chiba Section (the geological section at Tabuchi, Ichihara, Chiba Pref.) to be recognized as a Global Stratotype Section and Point (GSSP) to define the Lower-Middle Pleistocene boundary. The proposal was subsequently examined at the Working Group on L-M Boundary of the Subcommission on Quaternary Stratigraphy (SQS) of the International Commission on Stratigraphy (ICS) affiliated to the IUGS. In November 2017, the Working Group voted to approve the Chiba Section proposal and the result was reported to the executive committee of the IUGS. The IUGS later announced that a separate group from within Japan has raised objections to the proposal including casting doubt on the value of the scientific data used to support the proposal, and the final decision-making process of the IUGS has been suspended from April this year. As the largest Japanese academic society dedicated to field-based earth sciences, the Geological Society of Japan (JGS) decided it was important to take a role in this dispute and the Academic Research Section of the JGS undertook an examination of the proposal contents. This statement, for publication on our website, summarizes the results of the examination including a summary of the academic significance of the proposal. GSSPs are used for correlation between strata of a similar age throughout the world, and when deciding where to define the boundary of past geological ages, it is essential to select a section where strata that include the geological age boundary are continuously exposed and where the relevant stratigraphy has been closely documented using internationally recognized methods. -
Ratification of Subseries/Subepochs As Formal Rank/Units in International Chronostratigraphy
Communication of IUGS Geological Standards 1 by Marie-Pierre Aubry1, Werner E. Piller2*, Philip L. Gibbard 3, David A. T. Harper4, and Stanley C. Finney5 Ratification of subseries/subepochs as formal rank/units in international chronostratigraphy 1 Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08873, USA 2 Institute of Earth Sciences, University of Graz, NAWI Graz Geocenter, Heinrichstrasse 26, 8010 Graz, Austria; *Corresponding author: E-mail: [email protected] 3 Scott Polar Research Institute, University of Cambridge, Lensfield Road, Cambridge CB2 1ER, UK 4 Department of Earth Sciences, Durham University, Durham DH1 3LE, UK 5 Department of Geological Sciences, California State University, Long Beach, USA (Received: May 27, 2021; Revised accepted: July 8, 2021) https://doi.org/10.18814/epiiugs/2021/021016 The IUGS Executive Committee has voted unanimously should they remain informal subdivisions of series and epochs in a to ratify the proposal for formal adoption of the five-tiered hierarchy? This dilemma was at the heart of the conflicting posi- chronostratigraphical/geochronological unit divisions tions expressed in Head et al. (2017) and Pearson et al. (2017). A subseries/subepoch within the International Stratigraphic temporary resolution to the situation was recommended, so that sub- Guide as approved by the International Commission on commissions had the freedom to choose between formal and infor- Stratigraphy and forwarded to the IUGS EC on 24 March mal status based on individual preference (Finney and Bown, 2017). 2021**. The subseries/subepochs are now incorporated This led to glaring inconsistency in Cenozoic chronostratigraphy, in that the Subcommission on Quaternary Stratigraphy (SQS) adopted a in a six-tiered chronostratigraphic hierarchy of units that formal status for subseries whereas the subcommissions on Neogene are formally defined by a designated GSSP (Global Stage and Paleogene Stratigraphy (SNS and ISPS) continued to use sub- Stratotype and Point) at the base of designated type stages. -
INTERNATIONAL CHRONOSTRATIGRAPHIC CHART International Commission on Stratigraphy V 2020/03
INTERNATIONAL CHRONOSTRATIGRAPHIC CHART www.stratigraphy.org International Commission on Stratigraphy v 2020/03 numerical numerical numerical numerical Series / Epoch Stage / Age Series / Epoch Stage / Age Series / Epoch Stage / Age GSSP GSSP GSSP GSSP EonothemErathem / Eon System / Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) EonothemErathem / Eon System/ Era / Period age (Ma) Eonothem / EonErathem / Era System / Period GSSA age (Ma) present ~ 145.0 358.9 ±0.4 541.0 ±1.0 U/L Meghalayan 0.0042 Holocene M Northgrippian 0.0082 Tithonian Ediacaran L/E Greenlandian 0.0117 152.1 ±0.9 ~ 635 U/L Upper Famennian Neo- 0.129 Upper Kimmeridgian Cryogenian M Chibanian 157.3 ±1.0 Upper proterozoic ~ 720 0.774 372.2 ±1.6 Pleistocene Calabrian Oxfordian Tonian 1.80 163.5 ±1.0 Frasnian 1000 L/E Callovian Quaternary 166.1 ±1.2 Gelasian 2.58 382.7 ±1.6 Stenian Bathonian 168.3 ±1.3 Piacenzian Middle Bajocian Givetian 1200 Pliocene 3.600 170.3 ±1.4 387.7 ±0.8 Meso- Zanclean Aalenian Middle proterozoic Ectasian 5.333 174.1 ±1.0 Eifelian 1400 Messinian Jurassic 393.3 ±1.2 Calymmian 7.246 Toarcian Devonian Tortonian 182.7 ±0.7 Emsian 1600 11.63 Pliensbachian Statherian Lower 407.6 ±2.6 Serravallian 13.82 190.8 ±1.0 Lower 1800 Miocene Pragian 410.8 ±2.8 Proterozoic Neogene Sinemurian Langhian 15.97 Orosirian 199.3 ±0.3 Lochkovian Paleo- Burdigalian Hettangian proterozoic 2050 20.44 201.3 ±0.2 419.2 ±3.2 Rhyacian Aquitanian Rhaetian Pridoli 23.03 ~ 208.5 423.0 ±2.3 2300 Ludfordian 425.6 ±0.9 Siderian Mesozoic Cenozoic Chattian Ludlow -
Royal Society: Greenhouse Gas Removal (Report)
Greenhouse gas removal In 2017 the Royal Society and Royal Academy of Engineering were asked by the UK Government to consider scientific and engineering views on greenhouse gas removal. This report draws on a breadth of expertise including that of the Fellowships of the two academies to identify the range of available greenhouse gas removal methods, the factors that will affect their use and consider how they may be deployed together to meet climate targets, both in the UK and globally. The Royal Society and Royal Academy of Engineering would like to acknowledge the European Academies’ Science Advisory Council report on negative emission technologies (easac.eu/publications/details/easac-net), which provided a valuable contribution to a number of discussions throughout this project. Greenhouse gas removal Issued: September 2018 DES5563_1 ISBN: 978-1-78252-349-9 The text of this work is licensed under the terms of the Creative Commons Attribution License which permits unrestricted use, provided the original author and source are credited. The license is available at: creativecommons.org/licenses/by/4.0 Images are not covered by this license. This report can be viewed online at: royalsociety.org/greenhouse-gas-removal Erratum: The first edition of this report raeng.org.uk/greenhousegasremoval incorrectly listed the area of saltmarsh in the UK as 0.45 Mha, which is instead 0.045 Mha. This error has been corrected in the UK Cover image Visualisation of global atmospheric carbon dioxide scenario on p96 and the corresponding surface concentration by Cameron Beccario, earth.nullschool.net, GGR for habitat restoration adjusted. The using GEOS-5 data provided by the Global Modeling and Assimilation conclusions of this report and the UK net-zero Office (GMAO) at NASA Goddard Space Flight Center.