The Trials of Gaia: Milestones in the Evolution of Earth with Reference to the Anthropocene 3031237080, 9783031237089

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Andrew Yoram Glikson

The Trials of Gaia Milestones in the Evolution of Earth with Reference to the Anthropocene

The Trials of Gaia

In honor of James Lovelock. Wikimedia commons 1918–2022

Andrew Yoram Glikson

The Trials of Gaia Milestones in the Evolution of Earth with Reference to the Anthropocene

Andrew Yoram Glikson School of Biology Earth Environment Science (BEES) University of New South Wales Sydney, NSW, Australia

ISBN 978-3-031-23708-9 ISBN 978-3-031-23709-6 (eBook) https://doi.org/10.1007/978-3-031-23709-6 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Preface

Circling a yellow star for four and a half billion years, Earth—a living planet—spirals imperceptibly away from its mother sun, its colors alternating from ocean-blue and green brown lands, where life, an enigmatic force, has emerged in aqueous and terrestrial domains. Of all the explored solar system bodies, Earth is the only one known to harbor life, where evolution from unicellular organisms to intelligent arthropods, birds, mammals, and humans has taken place. As expressed by Carl Sagan (1980): “For we are the local embodiment of a cosmos grown to selfawareness’; We have begun to contemplate our origins: star stuff pondering the stars: organized assemblages of ten billion-billion-billion atoms considering the evolution of atoms; tracing the long journey by which, here at least, consciousness arose. Our loyalties are to the species and the planet. We speak for the Earth. Our obligation to survive is owed not just to ourselves but also to that Cosmos, ancient and vast, from which we spring”. Yet along with the forces which allow the emergence of life are the agents of death and destruction, including asteroid impacts, volcanic eruptions, glaciers, lethal gases, and anoxic atmospheres, ultraviolet radiation and ozone anomalies symbolized in the Hindu Brahma-Vishnu-Shiva triumvirate and the Ying-Yang couple. Such trios and duos dominate where organisms compete in reproduction, hunting and territorial rights. Deadly wars among the animals are common, among others between arthropods, corals polyps, and anemones. Fights are common among chimpanzees and gorillas, tigers, hippos, lions, crocodiles, lizards, kangaroos, and many others over reproductive rights, but murderous wars have reached their zenith among a species of ingenious biped mammals which has mastered the means of extinguishing large parts of the biosphere within a few centuries. Life on Earth is allowed thanks its shielding from fatal cosmic radiation by the atmosphere and its protection by the magnetic field. The anthropogenic exposure of Earth to nuclear radiation due to leaks from and explosion of nuclear devices is threatening all forms of life, as conveyed by Albert Einstein: “The splitting of the atom has changed everything, bar man’s way of thinking, and thus we drift toward unparalleled catastrophes”. Taking no heed of this warning, the species Homo “sapiens” has perfected a virtual doomsday machine under which it is still

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living on borrowed time. Believing it is “god-chosen” sapiens has rarely asked itself what has it been chosen for? The answer is blowing in the wind. Canberra, Australia

Andrew Yoram Glikson

Peer Reviews

I. Professor David Shearman AM, MB, ChB, PhD, FRACP, FRCPE. Emeritus Professor of Medicine at Adelaide University; previously at Edinburgh and Yale Universities; author of books on the science of climate change; served on the IPCC for two terms on health and climate sections. Former President of the Conservation Council of South Australia; With the late Professor Tony McMichael he founded Doctors for the Environment Australia in 2001 and was its Hon Secretary 2001–2018. Author and co-author of several hundred scientific and medical papers Awarded an AM for service to medicine and to climate change: ‘This book is for every person who has marveled at the stars, the moonlight and the beauty of our only home, planet Earth. It pays tribute to Lovelock who is the Einstein of thinking about the fragility of life on our Earth which he called Gaia. It follows Earth from its birth in a gaseous frenzy through its many ages to its coming fate from climate change caused by its dominant and uncontrolled species. The text shows remarkable skill in coordinating many scientific disciplines and the illustrations match the beauty of the Earth’.

II. Professor John (Charlie) Veron AO. John Edward Norwood Veron (known as “Charlie”), biologist, taxonomist, and specialist in the study of corals and reefs, is believed to have discovered more than 20% of the world’s coral species. Titled ‘The Godfather of Coral’, he received the Scientific Diving Lifetime Achievement Award, Darwin Medal, Silver Jubilee Pin of the Australian Marine Sciences Association and the Medal of the Order of Australia for “service to marine research”, 2021. I have come to expect a lot from Glikson’s publications and, once again, I’m not disappointed. The Trials of Gaia is the product of a creative multi-faceted thinker the likes of which I have seen nowhere else. From science to art, this book is brim-full of thoughts, all packaged to engage any reader. It has a bewildering content, the elements we may individually know about, but in composite forms a portrait of our planet we all need to understand, and above all, think about.”

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Peer Reviews

III. Professor Geoffrey Holland, Stanford University I have reviewed The Trials of Gaia. Your analysis feels pitch perfect to me. Personally, I think human survival depends on traditional male dominance giving way to a gender equal ‘Partnership Way’, and with that a commitment to planetary stewardship. The following is the blurb I have come up with for your important new book. ‘The Trials of Gaia by Andrew Yoram Glikson is a brilliant analysis of our own evolution as Earth’s apex species, and the planetary-scale perils that have emerged as a result of humanity’s arrogant cultural overreach. We all need to understand and fear the dark reality illuminated in this book.’ Geoffrey Holland—Author, The Hydrogen Age. Stanford MAHB.

IV. Professor Victor Gostin The book The Trials of Gaia by Andrew Glikson, is a wonderful straight-forward summary of all the known catastrophes that our planet has undergone since its birth. It is up-to-date in its coverage of the recent century and the overwhelming role that humanity has played during this time. It is a book I would recommend to my colleagues and those who have recently ‘discovered’ the wealth and excitement of earth-science information now available. While recent discoveries made by NASA space probes and the James Webb Telescope are creating enormous interest, the deep-time Earth record discussed by Glikson provides a very useful and authentic document of Earth history.

V. Professor R.T. Pigeon Professor of Geochronology, Curtin University. The “Trials of Gaia” is a comprehensive synthesis of the evolution and mysteries of life on Earth and early Earth history to stromatolites to extinction events and on climatic changes to the present day. It culminates in the rise of the hominids and the book follows the development and vulnerability of mankind to self destruct through nuclear war or climatic greenhouse progression. The book can be considered as two parts. First is a broad brush description of Early Planetary—Earth evolution focusing on early Earth and Moon, ancient rocks, early life, extinctions, snowball earth, climatic changes. It could be argued that some concepts could be pruned to smooth the presentation without losing the thrust. I think Patterson (1956) was the first to determine the age of the Earth and Solar System. Also, I don’t believe the cool early Earth concept of Valley, Moizsis, Wilde et al. The heavy oxygen in ~ 4Ga zircons can be explained by recent weathering. The second part looks at human nature, impacts of climate change in recent history, and the propensity of humans to self destruct. Following the discovery of nuclear reactions the development of bombs and missiles has left us with the very real possibility of nuclear war. Also, basically through population explosion, the human race is on an inexorable march to climate catastrophe through greenhouse gas production. On recent experience I would add that the human race is very threatened by some new form of pandemic. I saw a program recently that blamed the advent of pandemics on the

Peer Reviews

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fall of the Roman Empire. The book is a summary of the Author’s scientific experience and concern, or might I say despair, for the future of the human race. The compilation of knowledge is impressive. Quotes are relevant and figures and pictures are informative. There is a degree of repetition in the latter part. It has a staccato style, numerous references and scientific terms (e.g δ18 O, prokaryotic) that assumes readers have a strong scientific background.

VI. Professor Martin Van Kranendonk professor of Paleo-bio-geology, University of New South Wales. “They are fantastic contributions. And I appreciate that you have two sides of interest—the scientific and the more social/poetic aspects of our journey on this blue marble. And that is also wonderful. It’s how to combine them in a meaningful way and across what media and for what audience?”.

Acknowledgements

I am grateful to Brenda McAvoy, Professor David Shearman, the late Professor Will Steffen, Professor Bob Pidgeon, Professor Victor Gostin, Professor John (Charlie) Veron, Dr Helen Caldicott, Professor Robert Mann and Professor Martin Van Kranendonk and Professor Geoffrey Holland for scientific discussions, reviews and comments.

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Contents

1

The Living Planet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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The Dawn of Gaia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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The Early Earth Crust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Early Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27 35

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Ice Ages and Atmospheric Oxygenation . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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The Ediacaran to Cambrian “Explosion” of Life . . . . . . . . . . . . . . . . . . . 6.1 The Acraman Impact and Acritarchs Radiation . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

43 45 46

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Phanerozoic Mass Extinctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 Cambrian and Late Ordovician Mass Extinctions . . . . . . . . . . . . . . 7.2 Late and End-Devonian Mass Extinctions . . . . . . . . . . . . . . . . . . . . . 7.3 Late Permian and Permian–Triassic Mass Extinctions . . . . . . . . . . 7.4 End-Triassic Mass Extinction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 Jurassic-Cretaceous Extinction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 K-T (Cretaceous-Tertiary Boundary) Impact and Mass Extinction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 Paleocene-Eocene Thermal Peak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8 End-Eocene Freeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

47 48 49 50 51 51 52 53 53 54

The Holocene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1 The Younger Dryas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 The Neolithic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 The 4200 Years-Old Mega-Drought . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

59 59 60 63 65

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Contents

An Anthropogenic Catastrophe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.1 Carbon Emission and Climate Disruption . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

67 67 80

10 A Burning Planet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

83 87

11 Paleoclimate Implications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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12 Climate Zones Shifts, Ice Melt and Stadial Cooling . . . . . . . . . . . . . . . . . 97 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 13 Future Climate Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 14 The Nuclear Nightmare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 14.1 The Fermi Paradox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

About the Author

Dr. Andrew Yoram Glikson is an Earth and Paleo-climate scientist, a visiting scientist at the University of New South Wales, earlier of Geoscience Australia, the Research School of Earth Science, the School of Archaeology and Anthropology, Australian National University, and a member of the ANU Climate Change Institute. He graduated from the Universities of Jerusalem and Western Australia, conducted extensive geological surveys in Central and Western Australia, studied the evolution of the early Earth crust in several continents, investigated the effects of asteroid and comet impacts on the Earth with reference to the mass extinction of species, and studied the interrelationships between human evolution and the climate. He has an impact crater and an asteroid named after him by Eugene Shoemaker, the late head of the United States Astrogeology Branch of the US Geological Survey.

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The Living Planet

Like a magnificent comet, he illuminated the lives of millions, and we will not see his like again (Soter, 2000).

Circling a yellow star for four and a half billion years, Earth—a living planet— spirals imperceptibly away from its mother, its colors ranging from ocean-blue and green brown lands as life, an enigmatic force, emerges in aqueous and terrestrial domains. Of all the solar system bodies investigated to date Earth is the only one known to harbor life, where evolution from unicellular organisms to intelligent arthropods, birds and mammals, has occurred (Fig. 1.2). For eons photosynthesis in algae and plants emitted oxygen, transforming the Earth into a haven for sophisticated breathing life forms. In the Anthropocene, the cycle has been reversed, where a species of bipeds mammals is excavating, pumping and disseminating the toxic residues of life—coal, oil and methane—in the atmosphere and oceans, reversing the cycle of life. The phenomenon of Life, undergoing temporal evolution and transforming its environments, has led Lovelock (1972) to develop the Gaia hypothesis, a mythological personification of Earth where living organisms interact to form a self-regulating biological system that creates and maintains biochemical conditions and a planetary climate allowing it to evolve. Theories of the origin of life abound (cf. Choi et al., 2016; Glikson, 2019; Davies, 2000; Miller, 1953; Trefil et al., 2009). In principle the extreme adaptability of life to a wide range of environments renders it possible, even likely, for unicellular extremophile organisms (Merino et al., 2019) to exist elsewhere in solar system. But life is under constant attack by external forces—volcanic eruptions, asteroid impacts, abrupt changes in the composition of the atmosphere and oceans, toxic chemicals—which render the longevity of species in question. Lately the biosphere is assaulted by a species of intelligent primates, ironically named “sapiens”.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 A. Y. Glikson, The Trials of Gaia, https://doi.org/10.1007/978-3-031-23709-6_1

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1 The Living Planet

Fig. 1.1 Carl Sagan

The fundamental question of “why” versus “how” arises: What survival advantage is gained by the complex RNA and DNA molecules over their basic constituents, and what evolutionary explanation pertains to the development of their sophisticated architecture? Has the unique multicomponent micro-structures of the prokaryote and eukaryote cells been accidental, leading to functional advantages necessary for survival through a series of accidents and preferential retention, and leading to enrichment of the atmosphere in oxygen which allowed the synthesis of proteins and the evolution of advanced forms of life? But while the origin of life remains shrouded in mystery, the factors underlying the evolution of intelligence to levels allowing termites to build cities, bees to construct hives, birds to navigate the globe and biped mammals to decode the basic laws of physics remain inexplicable. The unknowns abound, for example can the brain fathom its own constitution? What exists outside the known universe? what preceded the Big Bang? How did the design of living cells emerge? How did the multicomponent architecture of Golgi in cells evolve? How have complex biological molecules, the RNA and DNA, evolved into organisms capable of decoding the basic laws of physics? Is causation reversible (Ellis, 2012)? What drives the directional evolution of swarm intelligence? Given the myriad interconnections between all life forms— microbes, plants, animals and their environments—the Gaia theory of planetary life constitutes a meaningful, though metaphoric, concept hardly resolved by experiment or calculation. It would constitute an absurd notion if the physical laws which allowed the emergence of life under favorable conditions would be confined to a single planet, although it is likely the majority of non-terrestrial life may be restricted to microbes. Very specific conditions must apply to biogenesis and evolution, although the probability is very high that such conditions apply in numerous instances throughout the Milky Way galaxy with it’s ~100–400 billion stars and

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their associated planets. Nor is it understood why there is little evidence for continuing creation of life on Earth despite favorable conditions for biogenesis (Davies, 2000)? Lovelock (1972) perceived numerous parallels between a living planet (Radford, 2019), and an individual organism. Gaia, the mother of Uranus sky god, the Titans, the Cyclopes, Pontus the sea god and the Giants, signify a living Earth dominated by an interconnectedness and interdependence of species. Inherent in life is its dependence on the surrounding media (Chu, 2016) constant transformation, dependence on sources of energy, shielding from harmful external forces and survival of the most adaptable. Whereas the basic formula of chemosynthesis and photosynthesis have been largely deciphered, the directional evolution of intelligence from organic matter to biological cells to sophisticated organisms and swarm intelligence are less well understood. Many unknowns remain regarding the evolution of swarm intelligence (Deneubourg & Theraulaz, 1992) that allows collective organisms to build nests, coral reefs and cities. Potentially little understood expressions of intelligence abound in nature, including genetically transmitted versus learnt behaviour. Examples abound, including the swarm intelligence of cooperative arthropods such as bee hives, termite nests, bird flocks, fish swarms, coral reefs and Human populations. Nor are the inherited genetic memories underlying the articulate designs of organisms and colonies such as spider webs, the solar and geomagnetic navigational skills of ants such as the Sahara Cataglyphis, or the global navigation of the Albatross fully deciphered by science, let alone the capacity of the human brain to decode its own constitution and the basic laws of physics (Glikson, 2019). Parallel with the huge achievements of science the unknowns remain overwhelming—leading to admiration of and a sense of reverence toward nature. The religions and spiritual cults hinge on anthropocentric interpretations of the unknown in terms of divine spirits, while unable to explain their nature and origin. Science has deciphered the basic laws of physics and chemistry (Sulloway, 2005), leaving essential questions unanswered, in particular the evolution of intelligence. In the process many modern humans have lost a sense of reverence toward nature (Neiman, 2013) which prehistoric people possessed, replacing it with the false egocentric notion promoting the “conquest” of Earth and even of space. While deciphering the “hows” humans turn a blind eye to the big question of “why”, for example why does directional evolution of intelligence exist in nature? According to Ward (2006) and others early examples of mass extinctions triggered by biological processes were related to ocean anoxia and acidification leading to CH4 and H2 S release by “purple” and “green” algae and sulphur bacteria. Likewise, anthropogenic global warming constitutes a geological/biological process for which the originating organisms, humans, have not to date been able to discover effective control. The critical criterion definitive of global warming is the atmospheric concentration of greenhouse gases, rising from 280 to near 420 ppm, i.e. by about 50% since pre-industrial time, only rarely mentioned by the media and politicians. Other parameters of climate change, such as the level of methane (Brand, 2016) and

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1 The Living Planet

Fig. 1.2 History of life on earth. Wikimedia commons

nitrous oxide, have risen about threefold. While opinions by journalists, politicians, economists and social scientists proliferate, less attention is given to what is indicated by climate science, rendering the global response to the looming calamity increasingly irrelevant. Thus, whereas most models portray linear rise in temperature, the breaching of the circum-Arctic jet stream, allowing cold and warm fronts to cross the boundary, leads to the breaking of the polar vortex and to high storminess in high latitudes. According to Wallace Broecker “The paleoclimate record shouts out to us that, far from being self-stabilizing, the Earth’s climate system is an ornery beast which overreacts to even small nudges, and humans have already given the climate a substantial nudge”. As stated by Hansen et al. (2012): “Burning all fossil fuels would create a different planet than the one that humanity knows. The palaeoclimate record and ongoing climate change make it clear that the climate system would be pushed beyond tipping points, setting in motion irreversible changes, including ice sheet disintegration with a continually adjusting shoreline, extermination of a substantial fraction of species on the planet, and increasingly devastating regional climate extremes”. The questions loom bigger than the answers (Fig. 1.1).

References

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References Brand, U. (2016). Methane hydrate: Killer cause of earth’s greatest mass extinction. Palaeoworld, 25(4), 496–507. Choi, H. M. et al. (2016). Mapping a multiplexed zoo of mRNA expression. Development, 143, 3632–3637, Cambridge, England. Chu, E. W. (2016). Environmental impact: Concept, consequences, measurement. https://doi.org/ 10.1016/B978-0-12-809633-8.02380-3 Davies, P. (2000). The fifth miracle: The search for the origin and meaning of life (p. 257). Amazon.com.au. Deneubourg, J. L., & Theraulaz, G. (1992). Swarm intelligence in social insects and the emergence of cultural swarm patterns. Santa Fe Instgitute, Paper #: 92-09-046. Ellis, G. (2012). Recognizing top-down causation. George, University of Cape Town. https://arxiv. org/ftp/arxiv/papers/1212/1212.2275.pdf Glikson, A. Y. (2019). From stars to brains: Milestones in the planetary evolution of life and intelligence (p. 159). Springer. Hansen, J., et al. (2012). Perception of climate change. Proceedings of the National Academy of Sciences, 109, 14726–14727. Lovelock, J. E. (1972). Gaia as seen through the atmosphere. Atmospheric Environment, 6, 579– 580. Merino, N., et al. (2019). Living at the extremes: Extremophiles and the limits of life in a planetary context. Microbial. https://doi.org/10.3389/fmicb.2019.00780 Miller, S. L. (1953). A production of amino acids under possible primitive earth conditions. Science, 117, 528–529. Neiman, S. (2013). Reason needs reverence: What we’ve yet to learn from the enlightenment. ABC Religion & Ethics. Radford, T. (2019). James Lovelock at 100: The Gaia saga continues. Nature Soter, S. (2000). Carl Sagan and the search for life. Publication of the New Press. © 2000 Am. Mus. Nat. History. Sulloway, F. J. (2005). The evolution of Charles Darwin. Smithsonian Magazine. Trefil, J., et al. (2009). The origin of life. American Science, ASTOR. Ward, P. D. (2006). Impact from the deep. Scientific American, 295(4), 64–71.

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The Dawn of Gaia

Echoes of a Beginning Tonight I barely hear a faint echo Escaping the starry plains Reaching Milky Way’s citadels Radiating 3 Kelvin mute, distant bells Whispering a surge of a beginning. Tonight I bathe in embryonic firmament Outpouring charmed strangeness, ambient Quarks, galaxies, ever-receding quasars Expanding in proton decay, searchlight pulsars Send me a signal I cannot decipher. Tonight I elude the primordial atom To you-and-me, here-and-now, I fathom Infinity, for a brief moment reaching Stardust exploring origins, switching The electromagnetic force bolts. Tonight I’m blinded by photons’ bright glare

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 A. Y. Glikson, The Trials of Gaia, https://doi.org/10.1007/978-3-031-23709-6_2

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2 The Dawn of Gaia Infant universes call each other, stare At ghostly neutrinos oblivious to God Swim the solar wind’s ether, they nod To eons aged nebula, crown of thorns. Tonight I’m touched by the swing Of life anti-life’s fatal sting Null state—when matter and antimatter Dance to the swing of the ether On a blue-green stage of a planet’s attire. Tonight muses within me inspire A pulsating seed, an ancient fire Of a primeval molecule, life’s sire Energized by your electron’s desire Seek expansion in love’s reunion. Tonight I’m drawn in verse Into a black hole, time’s end in reverse A new cosmos springing out of polarity Reincarnates at a point’s singularity Inscribed in invisible ink, I cannot decipher. Today, is there a wonder or horror This world is incapable of, the terror Does God play dice with life on this planet My hands clutch torn paper, a sonnet I brace myself—who am I? Poem by Andrew Glikson

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In the wake of the accretion of gas from the early solar nebula, leading to condensation of mineral dust and aggregation of meteorites under high-temperature low-pressure condensates (1300 °K; < 10–4 bar), CAI (Ca + Al + Mg + Ti) are found as inclusions in carbonaceous chondrites, a class of meteorites regarded as representative of pre-solar material. Close analogies between the composition of the chondritic meteorites and the bulk Earth suggests the composition of Earth is roughly what would be expected given the observed elemental abundances in the sun and accounting for the loss of the more volatile elements. Isotopic data suggest Earth formed a few tens of millions years following formation of the Sun while the oldest meteorites formed 4.56.109 years ago. The refractory elements are concentrated in the inner planets whereas the light elements and light compounds—hydrogen, helium, water, carbon dioxide, and ammonia concentrated in the gaseous outer planets, including Jupiter, Saturn, the Kuiper belt and the Oort cloud. Aggregation of dust, meteorites, planetesimals and planets from the solar nebulae about 4567.30 ± 0.16 Ma (Ivanova, 2016) over a period of tens of millions of years (Mezger et al., 2020) resolved by isotopic Mg–Al, Cr–Mn, Rb–Sr, Sm–Nd and Pb–Pb isotopes, determine the earliest sequence of planetary accretion. Textural and chemical data of chondritic meteorites suggest multiple melting and evaporation, possibly associated with shock waves within the protoplanetary disk. Fragments from sources outside the solar system were occasionally incorporated into solar orbit. One of the earliest theories regarding the origin of the Moon was conceived by George Darwin, the second son of Charles Darwin, who suggested a collision between a Mars-size planet termed Thea and the proto Earth, followed by accretion of the moon from the back-splash of the impact (Fig. 2.1). Evidence for this hypothesis includes (A) Earth’s spin and the Moon’s orbit have similar orientations; (B) The Earth–Moon system contains an anomalously high angular momentum, such as could have been caused by a giant impact; (C) The stable-isotope ratios of lunar and terrestrial rocks are identical, implying a common origin; (D) Depletion of lunar basalts in volatile elements and isotopically light elements, including F and Cl (Gargano et al., 2020) by near an order of magnitude, as compared to oceanic basalts, suggest their loss upon impact; (E) Lunar samples suggest the Moon was once molten down to great depth, supportive of melting by a giant impact; (F) The Moon has a relatively small iron core which could have been fused with the Earth core upon impact; (G) Evidence from other star systems of similar collisions, producing debris discs. Due to its giant size (radius 69,911 km; 1.898 × 1027 kg; gravity 24.79 m/s2 ) Jupiter exerts major influence on the inner planets, elongating their orbits as well as sweeping debris and planetoids from the asteroid belt, partly shielding Mars and Earth from deadly collisions, such as recorded by the Shoemaker-Levy comet in July of 1994 (Fig. 2.2). Gravitational accretion of Earth, radioactive decay and ongoing bombardment by planetesimals to considerable depth continued to heat the Earth and trigger mantle convection and likely plate tectonics. Calculations of rock properties suggest metallic fragments probably sank downward as Earth grew, contributing to the core.

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Fig. 2.1 An artist’s depiction of the Theia impact collision. Such an impact between Earth and a Mars-sized object is hypothesized to have resulted in formation of the Moon from the backsplash of the impacted early Earth. NASA NASA/JPL-Caltech. Public domain

Fig. 2.2 The collision of 21 fragments (with diameters of up to 2 km) of the Comet ShoemakerLevy-9 with Jupiter on 16 July, 1994, projected in advance by David Levy, Caroline Shoemaker and Eugene Shoemaker, constituted the first directly observed extraterrestrial collision in the solar system. It was photographed with a 40 cm Schmidt telescope at the Palomar Observatory in California. The fragmented nature of the comet is attributed to a previous approach to Jupiter in July 1992 within the Roche fragmentation limit. Impact speed is measured as 60 km/s NASA

Jupiter’s Eye A late night’s navigator by star-canopied sky The red giant looms big in my telescope’s eye

2 The Dawn of Gaia Latitudinal wind lanes, the fierce hurricane Engulf a red eye, deep, bizarre and arcane There from the abyss of the nebulous brain A wise octopus eye blinks this way once again Skirting dancing eddies of the Jovian sphere The cosmic lens stares, I imagine I hear: “My gravity pull of Galileo’s moons Crack ice on Europa as it orbits at noon Split cratered crust drifts on Calisto Trigger violent sulphur volcanoes on Io I, heavy eye-browed sky God of Olympus In war I beat Mars, fall enchanted with Venus But of all the planets that live in my reign I love Earthrise best, the blue life’s domain My right hand releases the life-giving rain Bless the just, in my left I hold with refrain Comets - divine thunderbolts striking my arch Foes on full moon—beware Ides of March! From Chaos’ eddies man’s ingenious mind Invents lies that rape Earth, once the blind Prometheus stole fire, when Pandora’s jar Let loose lethal rays, I watch from afar”. Slowly I take my red eyes from the lens My mind’s eye obtaining a hint, a mute sense

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2 The Dawn of Gaia Of an unfolding saga no one can prevent The red sentinel watches us in lament Poem by Andrew Glikson

The 4.567 Ga age of the solar system (Amelin et al., 2002), based on isotopic U–Pb ages of Ca–Al inclusions in carbonaceous chondrites, is consistent with the oldest age of Earth of 4.55 ± 0.01 Ga from lead isotopes in basic-ultrabasic layered complexes (Manhes et al., 1984), lunar samples (4.425 ± 0.02 Ga Maurice et al., 2020) and the oldest measured terrestrial zircons (< 4.404 Ga) from the Jack Hills, Western Australia (Wilde et al., 2001). This leaves a large part of terrestrial history between ~4.55 Ga and 4.03–3.94 Ga unknown. About half a billion years after Earth accreted a large cluster of asteroids impacted the Moon, as testified by large mare basins, including Oceanus Procellarum (d = 2568 km); South Pole Aitken (d = 2300 km), mare Frigoris (d = 1596 km), mare Imbrium (d = 1123 km), mare Tranquilitatis (d = 873 km), mare Nubium (d = 725 km), mare Serenitatis (d = 707 km), mare Nectaris (d = 373 km), mare Orientale (d = 327 km) and other, representing a Late Heavy Bombardment (LHB), based on the study of lunar samples collected during the Apollo missions from the large volcanic basins (Figs. 2.3, 2.4 and 2.5). With exceptions the largest mare basins face the Earth, possibly suggesting greater densities of the basalt basin fills and thus stronger gravitational pull toward the Earth. Whereas little or no evidence has been detected for lunar-like mare on Earth, a pre-existence of mare on Earth is more than likely in view of the proximity of the Moon and Earth in the Imbrian and the early Eratosthenian (~4 to 3 Ga) (Figs. 2.4 and 3.4). Little or no direct evidence has been detected to date of shock effects of the LHB in the oldest recorded terrestrial rocks, including in Greenland, Canada, Wyoming. South Africa and Australia (Glikson, 2014). Most likely such have been obliterated due to the high grade metamorphism of these terrains. Nor do ~4.4 Ga detrital zircons from Jack Hills, Western Australia, betray shock metamorphic evidence of impact (Cox et al., 2017). Nor have shock metamorphic features been identified to date in the 4.03–3.94 Ga Acasta Gneiss, northwest Canada (Bowring & Williams, 1999), ~3.8 Ga gneisses in northeastern Superior Province (Percival & Card, 1994), ~3,870 and 3620 Ma Itsaq gneiss and relic ~3760 Ma supracrustals of the Isua belt in southwestern Greenland, Swaziland gneisses and contemporaneous formations elsewhere. Analysis of 16 O–17 O–18 O isotope ratios (Rumble et al., 2013) have been interpreted in terms of their homogenization in an Hadean magma ocean, as does U–Th–Pb isotope dating of Hadean zircons, as a corollary of the lunar mare that likely existed following a collision of Earth (Valley et al., 2014) with a Mars-size planetoid. There is growing evidence the ~3.95–3.85 Ga-old Late Heavy Bombardment of the Moon was succeeded by intermittent bombardment of Earth by asteroids > 10 km-diameter and larger at least from ~3.5 Ga and likely earlier, as represented by well-preserved multiple impact ejecta units in supracrustal

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Fig. 2.3 History of the moon (Mann, 2018)

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Fig. 2.4 An evolution chart of the moon (NASA atlas of the solar system) https://gpm.nasa.gov/ image-use-policy

Fig. 2.5 An artist’s impression of the early earth, bombarded by solar system debris. Mann (2018). https://www.nature.com/articles/d41586-018-01074-6

greenstone sequences in South Africa and the Pilbara craton in Western Australia (Glikson, 2014). The composition of the Hadean crust remains unknown. Whereas the prevalence of silicic detritus in sediments containing the ~> 4 Ga zircons suggests derivation from granitoid terrains, selective weathering and disintegration of mafic material is also likely. According to Reimink et al. (2016): “Here we present new U–Pb and Hf isotope data on zircons from the only precisely dated Hadean rock unit on Earth,

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a 4,019.6 ± 1.8 Myr tonalitic gneiss unit in the Acasta Gneiss Complex, Canada. Combined zircon and whole-rock geochemical data from this ancient unit shows no indication of derivation from, or interaction with, older Hadean continental crust. Instead, the data provide the first direct evidence that the oldest known evolved crust on Earth was generated from an older ultramafic or mafic reservoir that probably occurred in the early Earth.” Different models pertain to the nature of the Hadean crust (Kamber, 2015). With the exception of detrital zircons as old as < 4.4 Ga, terrestrial relics of Hadean crust are likely to have been destroyed or incorporated in younger gneisses. Geochemical and isotopic inferences based on relic zircons and apatite inclusions suggest heavy oxygen 18 O/16 O isotope signature in ~4.3 Ga Hadean zircons in Jack Hills, consistent with low crystallization temperatures and presence of liquid water as early as ca. 4.3 Ga (Harrison et al., 2017; Mojzsis et al., 2001; Peck, 2001). Ti concentrations of Hadean zircons indicate a spectrum of crystallization temperatures ranging from a cluster at ~680 °C to values exceeding 1200 °C. In some interpretations the low temperatures indicate existence of hydrous melting conditions during the Hadean, although secondary alteration of the zircons (Fig. 2.6) may complicates interpretations. The prevalence of gneisses, as contrasted to relic supracrustal (greenstone) enclaves, in ~pre-3.8 Ga terrains implies extensive melting and re-melting of the Earth crust in the early Archaean and Hadean, leaving little record of surface processes. Surface evidence however becomes increasingly manifest in early Archaean terrain, such as the ~3.85 Ga Isua supracrustal belt in southwestern Greenland. Only minor clues are detected regarding possible Hadean environments suitable for existence of life. According to Valley (2005) and Trail (2007) high 18 O zircon oxygen isotope ratios suggest Hadean (> 3.85 Ga) zircon source melts were enriched in heavy oxygen, a proxy for hydrous source sediments. Thus “Zircon crystallization temperatures calculated from Ti concentration in pre-3.8 Ga zircons yield values of mostly ~680 °C low minimum-melt crystallization temperatures. Analysis of zircon/melt partitioning of rare earth elements (REEs) provide mutually consistent lines of evidence that the Hadean Earth supported an evolved cycle. This included formation of siliceous water-saturated melts, extensive continental crust, hydrosphere-lithosphere interactions, and sediment recycling within the first 150 million years of planet formation”. The terrestrial asteroid impact record during the Hadean remains unknown, except by inference from the lunar impacts. Migration of hydrothermal fluids to the surface has likely resulted in transient hot springs around volcanic loci where anaerobic biogenic activity and possibly photosynthesis may have occurred. The combination of volcanic activity, thermal metamorphism and impacts must have eliminated the bulk of the Hadean crustal record.

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Fig. 2.6 Cathode-luminescence image of a 400-μm Jack Hills zircon (Image credit: Oskin (2014); by permission of John Valley, University of Wisconsin)

References Amelin, Y., et al. (2002). Lead isotopic ages of chondrules and calcium-aluminum-rich inclusions. Science, 297(5587),1678–1683. Bowring, S. A., & Williams, I. S. (1999). Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada. Contributions to Mineralogy and Petrology, 134, 3–16. Cox, M. A., et al. (2017). The hunt for shocked zircon in the Jack Hills—21.000 and counting. Lunar and Planetary Science, XLVIII. Gargano, A. Y., et al. (2020). The Cl isotope composition and halogen contents of Apollo-return samples. Proceeding of National Academy of Science, 117(38), 23418–23425. Glikson, A. Y. (2014). The Archaean: Geological and geochemical windows into the early earth. In Modern approaches in solid earth sciences (vol. 9, p. 238). Springer, MASE. Harrison, T. M., et al. (2017). Hadean zircon petro-chronology. Reviews in Mineralogy & Geochemistry, 83, 329–363. Ivanova, M. A. (2016). Ca–Al-rich inclusions in carbonaceous chondrites: The oldest solar system objects. Geochemistry International, 54, 387–402. Kamber, B. (2015). The evolving nature of terrestrial crust from the Hadean, through the Archaean, into the Proterozoic. Precambrian Research, 258. Manhes, G., et al. (1984). U–Th–Pb systematics of the eucrite “Juvinas”: Precise age determination and evidence for exotic lead. Geochimica et Cosmochimica Acta, 48(11), 2247–2264. Mann, A. (2018). Bashing holes in the tale of Earth’s troubled youth: New analyses undermine a popular theory about an intense asteroid storm 4 billion years ago. Nature, 553, 393–395. Maurice, M., et al. (2020). A long-lived magma ocean on a young Moon. Science Advance, 6, 28.

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Mezger, K., Schönbächler, M., Bouvier, A. (2020). Accretion of the earth—missing components? Space Science Reviews, 216. Mojzsis, S. J. (2001). Oxygen-isotope evidence from ancient zircons for liquid water at the Earth’s surface 4,300 Myr ago. Nature, 409, 78–181. Oskin, B. (2014). Confirmed: Oldest fragment of early earth is 4.4 billion years old. https://www. livescience.com/43584-earth-oldest-rock-jack-hills-zircon.html Peck, W. H. (2001). Oxygen isotope ratios and rare earth elements in 3.3 to 4.4 Ga zircons: Ion microprobe evidence for high δ18 O continental crust and oceans in the Early Archean. Geochimica et Cosmochimica Acta, 65(22), 4215–4229. Percival, J., & Card, K. D. (1994). Geology, Lac Minto–Rivière aux Feuilles, Quebec. Geological Survey of Canada Map 1854A, scale 1:500 000. Reimink, J. (2016). No evidence for Hadean continental crust within Earth’s oldest evolved rock unit. Nature Geoscience, 9(10), 777–780. Rumble, D. (2013). The oxygen isotope composition of earth’s oldest rocks and evidence of a terrestrial magma ocean. Geochemistry, Geophysics, Geosystems, 14(6), 1929–1939. Trail, D. (2007). Constraints on Hadean zircon protoliths from oxygen isotopes, Ti-thermometry, and rare earth elements. Geochemistry Geophysics Geosystem. Valley, J. W., et al. (2014). Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography. Nature Geoscience, 7, 219–223. Valley, J. W. (2005). 4.4 Billion years of crustal maturation: oxygen isotope ratios of magmatic zircon. Contribution to Mineralogy and Petrology, 150(6), 561–580. Wilde, S. A., et al. (2001). Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago. Nature, 409, 175–178.

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Ancient Water No one Was there to hear The muffled roar of an earthquake, Nor anyone who froze with fear Of rising cliffs, eclipsed deep lakes And sparkling comet-lit horizons Brighter than one thousand suns That blinded no one’s vision. No one Stood there in awe Of an angry black coned volcano Nor any pair of eyes that saw Red streams eject from inferno Plumes spewing out of Earth And yellow sulfur clouds Choking no one’s breath.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 A. Y. Glikson, The Trials of Gaia, https://doi.org/10.1007/978-3-031-23709-6_3

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3 The Early Earth Crust No one Was numbed by thunder As jet black storms gathered Nor anyone was struck asunder By lightning, when rocks shuttered Engulfed by gushing torrents That drowned the smoldering ashes Which no one was to lament. With time Once again an orange star rose Above a sleeping archipelago Sun rays breaking into blue depth ooze Waves rippling sand’s ebb and flow Receding to submerged twilight worlds Where budding algal mats Declare life On the young Earth. A poem by Andrew Glikson

The early evolution of life on Earth involves exploration of the composition, structure, atmosphere, marine environment and sedimentation of Archaean evnironments. A decline is observed in metamorphic grade and thereby of geotherms and heat flow in supracrustal greenstone belts with time. Examples are the amphibolite grade of the Isukasia belt of southwest Greenland to the greenschist to zeolite facies of upper levels of early to mid-Archaean greensstone belts in the Pilbara craton (Fig. 3.1), Yilgarn, Barberton, Zimbabwe, Canadian, Dharwar greenstone terrains and elsewhere. Two alternative interpretations include (1) deeper crustal level of the earliest greenstone belts and thus higher grade metamorphism, and (2) higher degree of heat flow and contact metamorphism affecting the earliest supracrustal belts. Extensive mapping, isotopic and geochemical investigations in well-exposed and preserved Archaean greenstone belts in the Pilbara craton (Fig. 3.2) and

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Fig. 3.1 A photomontage representing Archaean stromatolites in an environment dominated by volcanic activity and asteroid impacts. Inserts a Asteroid Eros (NASA); b 2.63 Ma asteroid ejecta, Pilbara, Western Australia (courtesy of B.M. Simonson)

Barberton terrain (Figs. 3.3 to 3.5) including biogenic fossils, and surrounding granitoid batholiths, allow detailed insights into the Archaean evolution of these terrains (Hickman & Van Kranendonk, 2012). An evolutionary trend from mafic–ultramafic volcanic units to Na-rich tonalites and granodiorite intrusions is evident (Glikson, 2014; Glikson & Pirajno, 2018). Forming micro-continental nuclei, the younger cycles are characterized by more differentiated K-rich granodiorites and adamellites. Discoveries of near to 15 Archaean impact ejecta units up to 3.47 Ga-old intercalated with volcanic and sediments in Pilbara and Barberton greenstone belts, with clusters about 3.470–3.460 Ga, 3.3–3.227 Ga and 2.63–2.48 Ga, possibly represent terrestrial successors of an extended LHB? The interval ~3.25–3.22 Ga ago emerges as a major break in Archaean crustal evolution when, as indicated by a large body of field and isotopic age evidence, major asteroid bombardment resulted in faulting, large scale uplift, intrusion of granites and an abrupt shift from crustal conditions dominated by mafic–ultramafic crust to semi-continental nuclei represented by arenites, turbidites, conglomerate, banded iron formations and felsic volcanics. At this stage, the pre-3.2 Ga domestructured granite-greenstone systems were largely replaced by linear accretional granite-greenstone systems such as in the Superior Province in Canada, Yilgarn

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Fig. 3.2 Satellite image of the Pilbara Craton, Western Australia (NASA)

Craton and the western Pilbara Craton, compared by some authors to circumPacific arc-trench settings. A concentration of large impacts during 2.63–2.48 Ga potentially accounts for peak magmatic events culminating the Archaean era. Large impacts are capable of explaining some of the differences between Archaean and modern crustal models, including the relationships between the 3.26–3.24 Ga impact cluster, related unconformities, plutonic events and the onset of detrital sedimentation in the Barberton greenstone belt, as well as contemporaneous unconformities and megabreccia units in the Pilbara Craton, Western Australia. An onset of ferruginous sediments above impact ejecta units signifies extensive mafic volcanism and denudation of mafic volcanics producing Fe-rich sediments following impacts (Glikson & Hickman, 2014; Glikson & Vickers, 2006). Anhaeusser (1973), Glikson (1972), Viljoen and Viljoen (1969) interpret the 10 km-thick sequence of the 3.55–3.26 Ga Onverwacht Group of pillowed Mgrich quench basalts, peridotitic lavas and intrusive dolerite and gabbro intercalated with thin units of quartz- and feldspar-rich tuff and chert as relics of ancient oceanic crust. Lowe and Byerly (2010) suggested the Archaean asteroid bombardment may represent an extension of the LHB on Earth. A cluster of at least three asteroid impacts dated as 3.47–3.46 Ga in the Barberton and Pilbara overlaps the early Imbrian lunar period (Byerly & Lowe, 2019; Glikson, 2004; Lowe et al., 2003) (Fig. 3.4). Lunar impacts associated with Mare volcanism about ~3.2 Ga

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Fig. 3.3 Space image of the Barberton Mountain Land, Eastern Transvaal NASA

Fig. 3.4 Correlations of Archaean asteroid impacts between Western Australia and the Barberton greenstone belt, South Africa

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Fig. 3.5 The relations between Archaean asteroid impacts and mafic–ultramafic volcanics

(early Eratosthenian) correlate with a large impact cluster which affected Archaean greenstone-granite crust, triggering abrupt uplift. Sun and Nesbitt (1978) showed these Mg-rich lavas required high degrees of melting of the early mantle under high geothermal gradients. The common presence of mafic/ultramafic enclaves within granitoid gneiss and U–Pb and Sm–Nd evidence for sialic precursors of metasediments has led to contrasting interpretations, or a ‘chicken and egg’ impasse. A model portraying an asteroid impact, formation of unconformities, anatexis at the roots of sial nuclei and rise of granitoid magmas, is shown in Fig. 3.6. The relations between asteroid impact events and peak thermal events through time are portrayed in Fig. 3.7, suggesting possible correlations.

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a

b

d

c

Fig. 3.6 Model of the evolution of Pilbara greenstone belt. a ~3.26 Ga: formation of a multi-ring impact basin by a ~20 km-large asteroid, seismically triggered faulting, mantle rebound and onset of a new convection cell, thermal and anatectic effects across the asthenosphere–lithosphere boundary below sial nuclei. b ~3.26 Ga: Block faulting in sial nuclei, rise of anatectic granites, settling of ejecta spherules and their preservation below-wave-base environments; c ~3.24 Ga: impacts, ejecta fallout and preservation in below wave-base environments, further faulting, block movements and rise of plutonic magmas

Fig. 3.7 Relations between early asteroid impact events and peak isotopic ages

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References Anhaeusser, C. R. (1973). A discussion on the evolution of the Precambrian crust—The evolution of the early Precambrian crust of Southern Africa. Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences. Byerly, G. R., & Lowe, D. L. (2019). Geologic evolution of the Barberton greenstone belt—A unique record of crustal development, surface processes, and early life 3.55–3.20 Ga. In Earth’s Oldest Rocks (pp. 569–613). Glikson, A. Y. (1972). Early Precambrian evidence of a primitive ocean crust and island nuclei of sodic granite. Geological Society of America Bulletin, 83(11), 3323–3344. Glikson, A. Y. (2004). Early Precambrian asteroid impact-triggered tsunami: Excavated seabed debris flows exotic boulders and turbulence features associated with 3.47–2.47 Ga-old asteroid impact fallout units, Pilbara Craton, Western Australia. Astrobiology, 4, 1–32. Glikson, A. Y. (2014). The Archaean: Geological and geochemical windows into the early earth. In Modern approaches in solid earth sciences (vol. 9, p. 238). Springer, MASE. Glikson, A. Y., & Hickman, S. H. (2014). Coupled asteroid impacts and banded iron-formations, Fortescue and Hamersley Groups, Pilbara, Western Australia. Australian Journal of Earth Science, 61(5), 689–701. Glikson, A. Y., & Pirajno, F. (2018). Asteroids impacts (p. 215). Springer. Glikson, A. Y., & Vickers, J. (2006). The 3.26–3.24 Ga Barberton asteroid impact cluster: Tests of tectonic and magmatic consequences, Pilbara Craton, Western Australia. Earth and Planetary Science Letters, 241, 11–20. Hickman, A. H., & Van Kranendonk, N. J. (2012). Early earth evolution: Evidence from the 3.5– 1.8 Ga geological history of the Pilbara region of Western Australia. Episodes, 35(1), 283–297. Lowe, D. R., & Byerly, G. R. (2010). Did the LHB end not with a bang but with a whimper? The geological evidence. In 41st Lunar and Planetary Science Conference, p. 2563. Lowe, D. R., et al. (2003). Spherule Beds 3.47–3.24 billion years old in the Barberton Greenstone Belt, South Africa: A record of large meteorite impacts and their influence on early crustal and biological evolution. Astrobiology, 7–48. Sun, S. S., & Nesbitt, R. W. (1978). Petrogenesis of Archean ultrabasic and basic volcanics: Evidence from the rare earth elements. Contribution to Mineralogy and Petrology, 65, 301–325. Viljoen, M. J., & Viljoen, R. P. (1969). Archaean volcanicity and continental evolution in the Barberton region, Transvaal. In J. N. Clifford, J.P. Gass, (Eds.), African magmatism and tectonics (pp. 29–47). Oliver and Boyd.

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Early Life

The earliest recorded interaction between life forms and the planetary atmosphere is represented by colonial stromatolites, constituting cyanobacteria-dominated colonies with photosynthesis contributing limited amounts of oxygen to the local atmosphere, which in the long term created conditions for the emergence of complex animals. Subsequent evolutionary stages are represented by Eukaryotes, multicellular life forms, Arthropods, Molluscs, dinosaurs, birds, mammals and primates (Fig. 4.1). Archaean stromatolites occur in carbonate-silica intercalations in mafic–ultramafic and felsic volcanic units, representing inter-volcanic lulls. Old recorded traces of life (Nutman et al., 2016) discovered in 3700-Myr-old metamorphosed sediments in the Isua greenstone belt, southwestern Greenland, include 1–4-cm stromatolites—accretional laminated cyanobacterial structures within sedimentary units. The stromatolite mats occur in shallow marine carbonates and intercalated clastic sediments, including wave marks and breccia and marked by seawater-like rare-earth and yttrium trace element signatures. Younger biogenic records include stromatolites in the 3480-Myr-old Dresser Formation in the Pilbara Craton. However, it must be noted stromatolite-like structures have also been reported from a 731 meter-deep level of the Arabian Sea where photosynthesis is unlikely. Instead chemo-synthesis oxidation of methane may have occurred. Some of the earliest habitable environments may have been submarinehydrothermal vents (Dodd et al., 2017) containing uncertain putative microfossils 3770 million and possibly 4280 million years old in ferruginous sedimentary rocks from the Nuvvuagittuq belt in Quebec, Canada, interpreted as precipitate tube and filaments similar to filamentous microorganisms in modern hydrothermal vents. The rocks contain isotopically light carbon in carbonate and carbonaceous material as graphitic inclusions in diagenetic carbonate, apatite blades and magnetite– hematite granules. The rocks are associated with putative microfossils regarded as evidence for biological activity in submarine-hydrothermal environments more than 3770 million years ago.

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Fig. 4.1 Life Timeline from the Archaean to the quaternary

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Theories regarding the origin of a RNA world (Pearce, 2017) include: (A) hydrothermal vents in the deep-ocean, and (B) warm little ponds. Since the former lacks wet and dry cycles, such as are well known to promote polymerization of nucleotides into RNA, an origin in warm ponds may be more likely. A possible source of nucleobases is synthesis in hydrothermal vents around spreading cracks on young Earth’s ocean floors. RNA molecules are made up of sequences of four different nucleotides, one of which is formed through reaction of a nucleobase with a ribose and a reduced phosphorous source (Pearce, 2017). The evidence available to date does not make it clear to what extent asteroid impacts and other external factors influenced the biological evolution of prokaryotes (Figs. 4.2 and 4.3), cyanobacteria and Eukaryotes. Comprehnsive studies indicate that about two-thirds of the Early Archaean (~3.4–3.5 Ga), named Apex taxa, exhibit ‘cyanobacterium-like’ morphology (Schopf, 2006) (Fig. 4.2). Cyanobacteria comprise the evolutionarily most advanced lineage of the Bacterial Domain, capable of photosynthetic oxygen production and respiratory oxygen consumption (Blankenship, 1992). The presence early in Earth history of cyanobacterium-like putative fossils has been widely assumed to suggest that oxygenic photosynthesis and aerobic respiration, had already aevolved about ~3500 Myr ago. According to Schopf (1993) “it is conceivable that the external similarity of the Apex microorganisms to younger oxygen-producing cyanobacteria masks significant differences of internal biochemical machinery; thus, their morphology may provide a weak basis on which to infer paleophysiology”. It is not clear why extraterrestrial nucleobases are considered by some authors more suitable for biogenesis than those associated with terrestrial volcanics? Nucleobases found in meteorites (Petersil’ye & Pavlova, 1978) and formed experimentally (uracil, cytosine, and thymine) are suitable for synthesis as biomolecules. Unless temporally unique conditions existed when life originated on the early Earth no explanation (Davies, 2000) is at hand as to why the polymerization of nucleotides has not continued during younger periods of Earth history. In so far as it is assumed a weakly reducing early atmosphere was dominated by CO2 , N2 , SO2 , and H2 O (Trail, 2011) such a reducing media may not have been very suitable for synthesis of organic molecules according to Miller–Urey-type experiments. According to Chyba and Sagan (1992) organic molecules on the early Earth may have been derived either by endogenous production, exogenous delivery or impact-shock synthesis of organic molecules. The heliotropic (sun-oriented) growth patterns of most stromatolites suggest photosynthesis by domal cyanobacterial mats. The earliest life-like microfossils identified with confidence consist of filaments of the phylum Archeobacteria associated with hydrothermal vents cyanobacteria (blue-green algae) (Fig. 4.4) of the phylum bacteria. Cyanobacteria, photosynthetic prokaryotes, live in colonial dome-shaped aggregates denoted as stromatolites (Figs. 4.5, 4.6, 4.7, 4.8, 4.9, 4.10), able to perform oxygenic photosynthesis. Stromatolites are optimized for low oxygen conditions, including filamentous species in microbial mats in extreme environments—hot springs, hypersaline water, deserts and Polar Regions. Cyanobacteria range from

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Fig. 4.2 Fossil evidence of Archaean Life (Schopf, 2006). C. 2500–2700 Myr old Archaean microfossils photographed in petrographic thin sections. a–e Broad prokaryotic (Oscillatoriacean cyanobacterium-like) tubular sheaths (Siphonophycus transvalense) from the ca 2516 Myr old Gamohaan Formation of South Africa. f–k Solitary and paired (denoted by arrows) prokaryotic (bacterial or cyanobacterial) coccoidal unicells (Coffey et al., 2013) of Western Australia. By permission by J. W. Schopf

unicellular to filamentous and include colonial species. Cyanobacteria produce much of the world’s oxygen. Prochlorococcus (marine cyanobacteria), about 0.5– 0.8 µm (1/1000 mm) across, is ubiquitous between 40°N and 40°S. It is possibly the most plentiful species on Earth, accounting for production of about 20% of the oxygen in the Earth’s atmosphere. Some species are nitrogen-fixing. Modern analogues of ancient cyanobacteria occur in hydrothermal sea floor vents where diverse chemoautotrophic microbial communities include methanogens and methanotrophs, similar to microbial forms in ~3.5 Ga rocks in Western Australia and South Africa, along with structures of microbial cells coated by amorphous carbonaceous matter. A biogenic nature of Pilbara stromatolites is supported by the km-scale extent of the laminated sedimentary accretional reefs, studied in Shaw River outcrops of the Strelley Formation. Morphotype-specific analyses of the structures within their palaeo-environment are consistent with biogenic interpretation for their formation (Allwood et al., 2006, 2009) (Fig. 4.6). Locally well preserved microscale textures provide evidence of primary sedimentary processes, including inferred to probable

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Early Life

31

Fig. 4.3 Diagram of a typical prokaryotic cell. Wikimedia commons

benthic microbial mat formation. On the other hand to date microbial relics have not been confirmed in the recrystallized stromatolites, likely due to diagenetic alteration. The appearance of prokaryote single-cell cyanobacteria in the early Archaean and possibly earlier represents a unique development in the history of life. The occurrence of thin stromatolite-bearing sedimentary units built primarily by cyanobacteria (Awramik, 1991) between thick volcanic successions constitutes evidence for transient short-lived appearance and demise of biogenic activity during intervals between major volcanic outpours. The common occurrence of pillow lava in the volcanics, attesting to sub-aqueous subsidence, is contrasted with the development of shallow water platforms where heliotropic stromatolites developed through bio-mediated precipitation. Further diversification of stromatolites took place in the late Proterozoic (~1500–1200 Ma) in connection with an increase in

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Fig. 4.4 Diagram of a typical cyanobacterial cell Wikipedia commons

Fig. 4.5 3.49 Ga dresser formation, central Pilbara Craton, Western Australia. Photograph by the author. Photograph by the author

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Fig. 4.6 3.34 Ga Strelley Pool Chert, central Pilbara, Western Australia. Photograph by the author

Fig. 4.7 3.34 Ga Strelley Pool chert, central Pilbara, Western Australia. Photograph by the author

atmospheric oxygen, followed by a decline once grazing metazoans proliferated in the Vendian (~635 million to 541 Ma). Pilbara stromatolite occurrences include the 3.49 Ga, Dresser Formation, (Fig. 4.5), 3.34 Ga, Strelley Pool Formation, Figs. 4.6 and 4.7), 2.73 Ga (Tumbiana

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Fig. 4.8 2.73 Ga stromatolites, Tumbiana Formation, Eastern Pilbara, Western Australia. Photograph by the author

Fig. 4.9 2.73 Ga stromatolites, Tumbiana Formation, Eastern Pilbara, Western Australia. Photograph by the author

Formation, Figs. 4.8 and 4.9) and 2.63 Ga Carawine Dolomite (Fig. 4.10). Morphological types (Hoffman, 2000) include flat, convex, concave, globoidal, nodular, columnar and oncoidal forms.

References

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Fig. 4.10 2.63 Ga stromatolite, Carawine Dolomite, Eastern Pilbara, Western Australia. Photograph by the author

References Allwood, A. C., et al. (2006). Stromatolite reef from the Early Archaean era of Australia. Nature, 441, 714–718. Allwood, A. C., et al. (2009). Controls on development and diversity of Early Archean stromatolites. Proceedings of National Academy of Science, 106(24), 9548–9555. Awramik, S. M. (1991). Archaean and Proterozoic Stromatolites. In R. Riding, (Eds.), Calcareous algae and stromatolites. Springer. Blankenship, R. E. (1992). Origin and early evolution of photosynthesis. Photosynthesis Research, 33, 91–111. Chyba, C., & Sagan, C. (1992). Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules: An inventory for the origins of life. Semantic Scholar. https:// doi.org/10.1038/355125A0 Coffey, J. M., et al. (2013). Sedimentology, stratigraphy and geochemistry of a stromatolite biofacies in the 2.72 Ga Tumbiana Formation, Fortescue Group, Western Australia. Precambrian Research, 236, 282–296. Davies P. (2000). The fifth miracle: The search for the origin and meaning of life (p. 257). Amazon.com.au. Dodd, M. S., et al. (2017). Evidence for early life in Earth’s oldest hydrothermal vent precipitates. Nature, 543, 60–64. Hoffman, H. J. (2000). Archean Stromatolites as microbial archives. In R. E. Riding, & S. M. Awramik, (Eds.), Microbial sediments. Springer. Nutman, A. P., et al. (2016). Rapid emergence of life shown by discovery of 3700-million-year-old microbial structures. Nature, 537, 535–538. Pearce, B. K. D. (2017). Origin of the RNA world: The fate of nucleobases in warm little ponds. Earth, Atmospheric and Planetary Science, 114(43), 11327–11332. Petersilye, N., & Pavlova, M. A. (1978). Organic compounds in volcanic and metamorphic rocks. International Geology Review, 20, 339–344.

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Schopf, J. W. (1993). Microfossils of the early Archean apex chert: New evidence of the antiquity of life. Science, 260, 5108. Schopf, J. W. (2006). Fossil evidence of Archaean life. Philosophical Transactions of the Royal Society B: Biological Sciences, 361(1470). Trail, D. (2011). The oxidation state of Hadean magmas and implications for early Earth’s atmosphere. Pub. Medicine, 30, 480 (7375), 79–82.

5

Ice Ages and Atmospheric Oxygenation

The timing of both oxygen levels and biological evolution is tentative. Each major rise in oxygen is correlated with the proliferation of new oxygenic photosynthesizing cyanobacteria and later eukaryotes with primary plastids (algae, plants) (Fig. 5.1). The earliest recorded glaciation, the Huronian glaciation of 2.29–2.25 Ga (Tang & Chen, 2013) was accompanied by the Great Oxidation Event which includes a pre-2.3 Ga hydrosphere oxidation and post-2.3 Ga atmosphere oxygenation, lowering the atmospheric greenhouse effect through oxidation of methane. The origin of global glaciations is generally considered as a runaway effects (Chu, 2020) involving ice-albedo feedback, possibly triggered by reduction in incoming sunlight, ice albedo enhancement and expansion of ice. Sharp reductions in solar radiation are not unknown, for example the “Little Ice Age” in the sixteenth century, about 1650, about 1770 and in 1850, separated by mild warming intervals. Conversely volcanic activity likely contributed aerosols and thus cooling in the short term but contributed CO2 and thus greenhouse warming in the long term. There is little evidence for glacial deposits pre-2.9 Ga, which may be interpreted in terms of high concentrations of CO2 and CH4 in the Archaean atmosphere. A proliferation of eukaryote algae (Knoll et al., 2006) in the late Proterozoic is likely to have contributed to part oxygenation of the atmosphere and reduction of the greenhouse effect. The observation by Brian Harland, 1964 (Sohl & Chandler, 2002), of the association of warm water carbonates overlying glacial tillite at low paleo-latitudes constituted the initial evidence for a Snowball Earth theory. The origin of midlatitude glaciation if understood in terms of local oxygenation of atmospheric methane by photosynthetic release of oxygen (Kopp et al., 2005) by eukaryotes, appearing since the mid-Proterozoic (~1.5 Ga) (Fig. 5.2). The end of these condition was followed during 2220–2060 Ma by a major rise 13 C/12 C ratio defined as the Lomagundi–Jatuli Event, interpreted in terms of increased burial

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 A. Y. Glikson, The Trials of Gaia, https://doi.org/10.1007/978-3-031-23709-6_5

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Fig. 5.1 Early and late Proterozoic oxidation events, the rise of oxygen and the evolution of aerobic life. Figure redrawn by Michel Durinx, with the top part of the image based on Donaghue and Antcliffe (2010). Adapted with permission from Macmillan Publishers, Nature, © 2010. Permission by Springer Nature

of organic 13 C and a rise in atmospheric O2. This event, termed the Great Oxidation, is represented by the abundance of hematite and limonite-rich sedimentary red beds. Subsequent intermittent decline of the atmospheric greenhouse warming effect has led to more than one glaciation event. 2.3–2.2 Ga the Huronian glaciation (Kopp et al., 2005) and later the “snowball Earth” event ~750–580 Ma ago, extending to low latitudes of 11 ± 5° consistent with the “Snowball Earth” theory (Hoffman, 2011). Palaeomagnetic study of the 2450–2200 Ma-old Lorrain Formation, Quebec, which conformably overlies glacial deposits of the Huronian Gowganda Formation, indicate oxidation effects suggesting deposition at low latitudes (Schmidt, 2003). Based on paleo-magnetic evidence for an extension of the ice sheets to near the equator, Kirschvink et al. (2000) suggested that Earth’s oceans and land surfaces were intermittently covered by ice from the poles to the Equator during at least two extreme cooling events between 2.4 billion and 580 million years ago. Further definitions of glacial events are provided by isotopic age correlations of paleo-Proterozoic units were conducted by Rasmussen (2013).While proliferation of stromatolites has led to local and transient oxygenation events, the evolution of Eukaryote algae plants led to alterations of the composition of the atmosphere and

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Ice Ages and Atmospheric Oxygenation

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Fig. 5.2 Comparison between Eukaryotic cells (possessing membrane-bound nucleus) (left) and Prokaryotes cells (right). National Center for Biotechnology Information, Public Domain

Fig. 5.3 Glacial diamictite of the 2.9 Ga Pongola Supergroup

the climate (Evarts, 2017) due to transpiration and offset temperature and moisture levels. The earliest recorded glacial event is represented by diamictites of the 2.9 Ga-old Pongola Supergroups in Swaziland (Fig. 5.3). The best documented glacial episodes occur in the Cryogenian, about 720–635 Ma age (Fig. 5.4), termed “Snowball Earth” (Fig. 5.5). Late Proterozoic Cryogenian (720–635 Ma) glaciers have reached sea level almost globally. U–Pb and Rh–Os isotopic age evidence indicates ice sheets reached sea level at all latitudes during two long-lived Cryogenian global glaciations, the Sturtian (717–643 Ma) and the Marinoan (650–632.3 Ma). Uranium-lead and rhenium-osmium isotopic age dating suggest that both the Sturtian glacial onset and the Marinoan glacial termination were globally synchronous. Geochemical data imply CO2 was ~1300 ppm, O2 ~60% of modern level (i.e. 22.57%) and

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Fig. 5.4 Multiple glacial events during the Cryogenian, including the Sturtian and Marinoan https://en.wikipe dia.org/wiki/Sturtian_glacia tion

mean temperature ~5 °C. The Sturtian glaciation followed continental breakup and major igneous activity (Hoffman et al., 2017). According to these authors this led to a net snow and frost accumulation and thickening of oceanic ice forming a sea glacier flowing gravitationally toward the equator, sustained by the hydrologic cycle and by basal freezing and melting. Terminal carbonate deposits, unique to Cryogenian glaciations, are products of intense weathering and ocean stratification. Whole-ocean warming allows marine coastal flooding to continue long after ice-sheet disappearance.

References

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Fig. 5.5 An example of a glacial dropstone from Namibia (Poppick, 2019) in rocks that date to the second Snowball Earth. The stone was likely carried and dropped by a floating ice shelf, and when it plunked into seafloor sediment below, that sediment folded around it. By permission of Paul Hoffman

During the Sturtian glaciation (717–643 Ma), lasting for 50–60 million years, much of the Earth surface was covered by ice, while during the Marinoan glaciation (650–632.3 Ma) ice dominated the Earth surface for about 17 million years. A connection between these glaciations and volcanism associated with the breakdown of the Rodinia paleo-continent and the onset of the Laurentian basalt province have been suggested. Long term enrichment of the atmosphere in CO2 associated with the volcanism is likely. The termination of the Snowball Earth glaciation episodes was related to increase in atmospheric CO2 levels, represented by the Cap carbonates overlying the glacial tillite and attesting to the rise of greenhouse gas levels and thereby high temperature and melting of the glaciers.

References Chu, J. (2020). A plunge in incoming sunlight may have triggered “Snowball Earths”. MIT News Office. Donoghue, P. C. J., & Antcliffe, J. B. (2010). Early life: Origins of multicellularity. Nature, 466(7302), 41–42. Evarts, H. (2017). How vegetation alters climate. Columbia Engineering, Stanford Earth Matters Climate Change. https://earth.stanford.edu/news/how-vegetation-alters-climate#gs.22ezua

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Hoffman, P. F. (2011). A history of Neoproterozoic glacial geology, 1871–1997. GeoScienceWorld Books. https://doi.org/10.1144/M36.2 Hoffman, P. F., et al. (2017). Snowball earth climate dynamics and Cryogenian geologygeobiology. Science Advance, 8.3(11), e1600983. Kirschvink, J. L., et al. (2000). Paleoproterozoic snowball Earth: Extreme climatic and geochemical global change and its biological consequences. Proceedings of National Academy of Science, 97(4), 1400–1405. Knoll, A. H., et al. (2006). Eukaryotic organisms in Proterozoic oceans. Philosophical Transactions of the Royal Society B: Biological Sciences, 361(1470), 1023–1038. Kopp, R. E., et al. (2005). The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis. Proceeding of the National Academy of Science, 102(32), 11131–11136. Poppick, L. (2019). Snowball earth: The times our planet was covered in ice. Astronmy. Rasmussen, B. (2013). Correlation of Paleoproterozoic glaciations based on U–Pb zircon ages for tuff beds in the Transvaal and Huronian Supergroups. Earth and Planetary Science Letters, 382, 173–180. Schmidt, P. W. (2003). Paleomagnetism of the Lorrain Formation, Quebec and the implications for the latitude of the Hudsonian glaciation. EGS—AGU—EUG Joint Assembly, Abstract Id., 8262, 6–11. Sohl, L., & Chandler, M. (2002). Did the snowball earth have a Slushball ocean? NASA. Goddard Space Flight Center. Tang, H., & Chen, Y. (2013). Global glaciations and atmospheric change at ca. 2.3 Ga. Geoscience Frontiers, 4, 583–596.

6

The Ediacaran to Cambrian “Explosion” of Life

The Ediacaran is a geological period that spans ~ 96 million years from the end of the Cryogenian at ~ 635 Ma to the onset of the Cambrian at ~ 539 Ma. According to Knoll et al. (2006) the Ediacaran Period constitutes a distinctive interval of time bounded by the decay of the great Marinoan ice sheets and the beginning of the Cambrian radiation of life. It marks the end of the Proterozoic Eon, and the beginning of the Phanerozoic Eon. It is named after the Ediacara Hills of South Australia. The onset of the Cambrian “explosion” of life between ~541 Ma and 530 million years ago, when many of the major animals groups first appear in the fossil record, involved a unique proliferation of organisms, including about 20 and 35 major phyla signifying the emergence of modern animal life (Gould, 1990) (Figs. 6.1 and 6.2). This involved evolution of animal body plans, episodic bio mineralization, pulsed change of generic diversity, body size variation, and progressive increase of ecosystem complexity (Zhang & Shu, 2021). According to these authors the Cambrian radiation occurred in three stages, including pulsed change of generic diversity, body size variation and progressive increase of ecosystem complexity. Some groups succeeded temporarily while others were ephemeral and represented by only few taxa. The diversity of stem groups led to morphological gaps across phyla as witnessed at present. Arthropods and chordates exhibit a progressive diversification in the Phanerozoic. Like other evolutionary developments ecological factors were in the core of the Cambrian Explosion of life, which is regarded as a polythetic sharing a number of characteristics due to multiple factors Fig. 6.2. It is likely that a major factor in the Cambrian radiation of life resides in an enrichment of sea water in oxygen, as aerobic respiration based on oxygen provides metabolic energy about 18 times as efficient as anaerobic respiration. The evidence includes episodic radiations of major phyla coincident with variations in carbon isotopes. The authors report carbon and sulfur isotope data for marine carbonates which overlap early Cambrian radiations between ~524 to ~514 Myr ago, indicating covariations between carbonate δ13 C and sulfate δ34 S values in © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 A. Y. Glikson, The Trials of Gaia, https://doi.org/10.1007/978-3-031-23709-6_6

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Fig. 6.1 Ediacara fauna, Flinders Ranges, South Australia: Diorama of Ediacaran sealife displayed at the Smithsonian Institution. Wikipedia common

Fig. 6.2 A cast of Dickinsonia Costata. Wikiedia commons

6.1 The Acraman Impact and Acritarchs Radiation

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Fig. 6.3 Reconstructing ancient atmospheric O2 , Wikipedia commons. a no oxidized iron found; b oxidized iron bands in seabed rock = evidence for O2 in oceans; c oxidized iron bands on land; ozone layer formation = evidence for O2 in atmosphere; biological events: (1) earliest fossilized cells found; (2) photosynthetic bacteria start producing O2 ; (3) aerobic metabolism evolves.; (4) evolution of multicellular plants starts; (5) evolution of animals begins

five isotopic cycles, representing oscillations in atmospheric O2 and the extent of shallow-ocean oxygenation. The fluctuations in oxygen in shallow marine realm exerted control on the biodiversity of faunal radiations (Fischer, 2016). According to Zhang et al., (2016) based on total Carbon and trace element ratios (V/Al, Mo/Al, U/Al) oxygen levels between above 0.5%–4% present atmospheric level (PAL) existed locally allowing sufficient oxygen levels for sponges, photosynthesis and, as compared with but reached about ~10% of PAL in the Cambrian. Marked fluctuations in the level of O2 continued through the Cambrian and successive eras, accounting to appearance and disappearance of species Fig. 6.3

6.1

The Acraman Impact and Acritarchs Radiation

The ~ 580 Ma Acraman impact structure, estimated as ~90 km in diameter (Gostin, 1986; Gostin, 1999; Williams et al., 1996), and a related ejecta layer found up to 550 km away from the crater, postdate the Marinoan glaciation (650–635 Ma). The impact was closely followed by radiation of Acritarch phytoplanktons, including an abrupt change from Ediacaran leiosphere palynoflora (ELP) to Ediacaran complex Acritarchs palynoflora (ECAP), presenting the oldest example of biological radiation following large catastrophic events (Grey, 2005; Grey et al., 2003). The sequence from the terminal glacial sediments of the Cryogenian (~635 Ma) to the

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base Cambrian includes: (1) Cap carbonates, representing likely greenhouse gasdriven glacial collapse; (2) clastic sediments; (3) the ~580 Ma Acraman impact ejecta overlain by the Acritarchs-radiation horizon; (4) Ediacara fauna ~550 Ma and (5) ~544 Ma base Cambrian. The Acraman event is associated with marked negative δ13 C anomalies which signify increased deposition of organic matter (Calver, 2000; Walter et al., 2000).

References Calver, C. R. (2000). Isotope stratigraphy of the Ediacarian (Neoproterozoic III) of the Adelaide rift complex, South Australia, and the overprint of water column stratification. Precambrian Research, 100, 121–150. Fischer, W. W. (2016). Breathing room for early animals. Proceedings of the National Academy of Sciences of the United States of America, 113(7), 1686–1688. Gostin, V. A. (1986). Impact ejecta horizon within late Precambrian shale, Adelaide Geosyncline, South Australia. Science, 233, 198–200. Gostin, V. A. (1999). Petrology and microstructure of distal impact ejecta from the Flinders ranges Australia. Metoritics & Planetary Science, 34, 587–592. Gould, S. J. (1990). Wonderful life: The Burgess Shale and the Nature of History Paperback (p. 352). Grey, K. (2005). Ediacaran Palynology of Australia (p. 439). Association of the Australasian Palaeontologists Memoir 31. Grey, K., et al. (2003). Neoproterozoic biotic diversification: Snowball earth or aftermath of the Acraman impact? Geology 59–462. Knoll, A. H., et al. (2006). Eukaryotic organisms in Proterozoic oceans. Philosophical Transactions of the Royal Society B: Biological Sciences, 361(1470), 1023–1038. Walter, M. R. (2000). Dating the 840–544 Ma Neoproterozoicinterval by isotopes of strontium, carbon, and sulphur in seawater, and some interpretative models. Precambrian Research, 100, 371–433. Williams, G. E., et al. (1996). Magnetic signature and morphology of the Acraman impact structure South Australia. Geological Survey of Organisation Journal of Australian Geology and Geophysics, 16, 431–442. Zhang, S., et al. (2016). Sufficient oxygen for animal respiration 1,400 million years ago. Proceedings of the National Academy of Sciences of the United States of America, 113, 1731–1736. Zhang, X., & Shu, D. (2021). Current understanding on the Cambrian explosion: Questions and answers. Paläontologische Zeitschrift, 95, 641–660.

7

Phanerozoic Mass Extinctions

Five major mass extinction events and several moderate extinction events affected the evolution of marine invertebrates and other species. High-resolution regional palaeoecological studies indicate extensive ecological upheaval, high species-level turnover and recovery intervals lasting millions of years, with close correlations to upheavals affecting terrestrial vegetation (McElwain & Punyasena, 2007). The geological record betrays a close correspondence between paleontological, sedimentary, volcanic, asteroid impact events, rising CO2 and methane and resulting paleo-temperature trends, allowing identification of environmental factors which underlie the evolution and extinction of species (Beerling, 2002a, 2002b; Glikson, 2005; Keller, 2005; McElwain et al., 1999). When an asteroid with a diameter > 200 m hits Earth at a high angle, penetrating the surface to approximately × 1.5 times its diameter, depending on the rheology of the target rocks where kinetic energy translates into heat, it triggers fragmentation, an explosion, cratering, melting and vaporization of the surrounding rocks. In craters larger than about 4 km the crust rebounds, forming a central uplift (French, 1998; Glikson, 2013; Pilkington & Grieve, 1992). Depending on the size of the impact, seismic waves propagate, triggering earthquakes, faulting and tsunami waves. Environmental effects include an initial fireball flash, megatsunami waves, ejection of dust, sulphur dioxide, carbon soot, acid rain and release of greenhouse gases including water, CO2 , methane and Nitrous oxide, leading to ocean acidification. The consequence is an “asteroid winter” phenomenon, where some 10–20% of solar radiation is blocked for 8–13 years (Pope et al., 1997), succeeded by a greenhouse warming for centuries to millennia, affecting species which escaped the immediate transient regional effects impacts. The longevity of CO2 in the atmosphere over thousands to tens of thousands years (Eby et al., 2009; Solomon et al., 2009) leading to prolonged warming, with compounding effects on the biosphere. Effects on the oceans include acidification, anoxia and emanation of toxic H2 S due to decreasing oxygen solubility with temperatures (Ward, 2007).

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Mass extinctions marked by carbon and oxygen isotopic signatures occur in the End-Ordovician (Brenchley et al., 2003; Marshall, 1992; Marshall et al., 1997), Late Devonian, Permian–Triassic boundary, Late Triassic and the K-T boundary (Maruoka et al., 2007). Changes in the carbon cycle recorded by total organic carbon (TOC ) and stable carbon isotope ratios (δ13 Ccarb and δ13 Corg ) form sensitive fingerprints of mass burial of organic matter derived from marine organisms, fallout from forest fires or changes in biological productivity. Variations in oxygen isotope ratios (δ18 O) reflect changes in ice volumes and salinity. Marked changes in these parameters accompany major volcanic eruptions, asteroid impacts (Maruoka et al., 2007) and methane release (Zachos et al., 2008). Positive excursions in both δ18 O and δ13 Ccarb at the end-Ordovician signify parallel decrease in temperature and in biological productivity at the onset of 443.4 ± 1.5 Myr Ashgill/Hirnatian glaciation and extinction event (Brenchley et al., 2003; Marshall, 1992; Marshall et al., 1997). A global nature of the glaciation is indicated from the widespread positive carbon isotope, including δ13 Ccarb and δ13 Corg , and oxygen isotope shifts measured from Brachiopod shells over a wide range of paleo-latitudes. Upper Ordovician cores from Estonia and Latvia record a δ13 Ccarb shift of up to 6‰ and similar profiles were measured in Nevada, suggesting a global chronostratigraphic signal (Brenchley et al., 2003). Positive correlation between δ13 C and δ18 O militates for genetic relations between biological activity and temperature.

7.1

Cambrian and Late Ordovician Mass Extinctions

The end—Ordovician period, marked by a glaciation about ~445.6–443.7 Ma and possibly longer (Frakes et al., 1992), saw two phases of extinction involving ~57% of genera (Hallam & Wignall, 1997), including pelagic graptolites and most benthic groups (trilobites, brachiopods, bryozoans, echinoderms). A principal underlying factor for the cooling, glaciation and mass extinction is considered to have been the very large asteroid impact represented by the ~510 km-diameter Deniliquin impact structure (Fig. 7.1; Glikson & Yeates, 2022). Factors driving the extinction included cooling, glaciation, sea-level regression and major changes in oceanic circulation, leading to extinction of pelagic groups including graptolites and conodonts. The second phase appears to have been related to warming and ocean bottom anoxia eliminating shelf habitats (Hallam & Wignall, 1997; Keller, 2005). According to Kump et al. (1999) CO2 levels declined during the glaciation from 5000 to 3000 ppm, inducing cooling amplified by low insolation about 4% lower than at present level of 342 W/m2 . The geophysical evidence for a large (~520 km diameter) multiple-ring feature under the Murray Basin, southeastern Australia (Glikson & Yeates, 2022; Yeates et al., 2000), likely representing the deep-seated root zone of a large late Ordovician impact structure, raises the possibility of a late Ordovician impact-triggered mass extinction. Principal features of the feature include (A) a multiple ring total magnetic intensity (TMI) pattern; (B) a central quiet magnetic zone; (C) circular

7.2 Late and End-Devonian Mass Extinctions

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Fig. 7.1 A TMI image of the Deniliquin mega-impact structure and surrounds and of the location of drill holes that penetrated the basement below the Murray Basin. Geoscience Australia. Arrows mark radial fault lines accompanied by magnetic anomalies (Glikson & Yeates, 2022)

Bouguer gravity patterns; (D) an underlying mantle Moho rise about 10 km shallower than under the adjacent Tasman Orogenic Belt; (E) radial faults associated with magnetic and demagnetized anomalies (Fig. 7.1).

7.2

Late and End-Devonian Mass Extinctions

Late Devonian mass extinctions include volcanism of the Viluy Traps, East European platform, estimated as > 510,000 km3 and dated in the range 377 and 350 Ma (Keller, 2005). The end-Devonian at ~360 Ma was marked by a large asteroid impact cluster including Woodleigh (D = 120 km), Alamo (D = 100 km), Charlevoix (D = 54 km) and Siljan (D = 52 km) and possibly Warburton East and Warburton West (D~400 km). Devonian mass extinction events (Hallam &

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Phanerozoic Mass Extinctions

Wignall, 1997; McGhee, 1996) include a ~387 Ma extinction (~30% of Genera) and ~374 Ma extinction (58% of Genera), affecting pelagic fauna (Ammonoids, Cricoconaids, Placoderms, Conodonts, Agnathans) and benthic groups (Rugose corals, Trilobites, Ostracods and Brachiopods). The extinction involved collapse of Stromatoporoid reefs (Keller, 2005). End-Devonian ~359 Ma extinction (~30% of Genera) affected fish (Placoderms), ammonoids, conodonts, stromatoporoids, rugose corals, trilobites and ostracods. Major factors included ocean anoxia, declining biological activity (high δ13 C), and warming (low δ18 O) (Balter et al., 2008). The late Devonian mass extinctions are superposed on a protracted cooling trend associated with a decline in CO2 levels from a range of ~3200–5200 ppm to below ~500 ppm. Concomitant decline in δ13 C from ~22 to ~15‰ from ~405 Ma to 280 Ma is indicated by paleosols (Mora et al., 1996). The development in the Late Devonian of plant megaphyll leaves with their branched veins containing high stomata density allowed vegetation to adapt to the cool low-CO2 conditions of the Carboniferous-Permian (Rothwell, 1989; Beerling et al., 2001).

7.3

Late Permian and Permian–Triassic Mass Extinctions

Major eruptions of the Siberian Norlisk magmatic province and Emeishan volcanism (Renne et al., 1995; Wignall, 2001; Wignall & Twitchett, 1996) about ~251 Ma (251.7 ± 0.4 to 251.3 ± 0.3 m.y., Kamo, 2003) and a large asteroid impact (Araguinha, Brazil, D = 40 km, ~247.8 ± 3.8 Ma; Tohver et al., 2012), which excavated carbonates and shale (Table 2.1), has led to a rise of atmospheric CO2 levels to ~3400 ppm (Royer, 2006), associated with the largest mass extinction recorded in geological history. Two major extinction phases are defined: (A) ~50% of genera extinguished at the ~260 Ma Late Permian Maokouan Stage. Tropical zones saw the extinction of echinoderms, corals, Brachiopods, Sponges, Fusulinid Foraminifera and Ammonoids (Keller, 2005; Ross & Ross, 1995) (B) ~78% of genera extinguished at the ~251 Ma end-Permian Changhsingian Stage, effecting abrupt extinction of the Rugose Corals, Bryozoans, complex Foraminifera, many Gastropod and Bivalve families, radiolarians and many Ammonoid families (Hallam & Wignall, 1997; Racki, 2003). The two events were separated by the Capitanian and Wuchiapingian Stages (265.8–253.8 Ma) (Keller, 2005). An abrupt nature of these events is indicated by their short duration of 10–50.103 years and negative δ13 C excursion indicating deposition of fauna and flora remains (Twitchett et al., 2001). Nektonic (free swimming) fauna, including fish, Conodonts and Nautiloids survived better thanks to their mobility in the upper water column above anoxic bottom water (Keller, 2005). Anoxia is evidenced by sulphide-rich and black clay sediments and negative δ13 C anomalies testifying to mass settling of organic matter. Grasby et al. (2011)

51

suggested a link between extinction and a release of carbon ash/char derived from the combustion of Siberian coal and organic-rich sediments by flood basalts, which was dispersed globally and created toxic marine conditions. Berner (2005) investigated geochemical trends across the Permian–Triassic boundary from isotopic δ13 C and δ34 S mass balance and estimates of weathering and burial of carbon and sulphur. A drop in the rate of organic burial from the late Permian to the midTriassic is attributed to rising aridity and decrease in biomass due to a transition from forests to herbaceous grassland. A major drop in oxygen from 30 to 13% was associated with an increase in the ratio of pyrite to organic carbon and in development of marine euxinic basins. Consequences included extinction of vertebrates and loss of giant insects and amphibians. According to Ward (2007) ocean acidification due to rising CO2 levels, polar ice melt, reduced ocean current system and the conveyor belt which provides oxygen, consequent anoxia, production of H2 S by sulphur-reducing microbes and its release to the atmosphere, constituted critical factors in ocean and land mass extinction.

7.4

End-Triassic Mass Extinction

The opening of the Central Atlantic magmatic province by the end-Triassic at ~ 200 Ma, involving copious basaltic volcanism (Courtillot & Rennes, 2003; Hames, 2003; Jourdan et al., 2009) affected a major mass extinction event represented by a large negative carbon isotope excursion, reflecting perturbations of the carbon cycle, including an increase in CO2 (Beerling, 2002a; Whiteside et al., 2010). The end-Triassic was preceded by a Norian (~216–213 Ma) extinction associated with the large Manicouagan impact (D ~ 100 km; 214 ± 1 Ma). The extinction affected ammonites, reef organisms, conodonts and bivalves, as well as a crisis in terrestrial plants (Hallam & Wignall, 1997; Keller, 2005). The duration of the extinction is variously estimated as between 50 and 200 kyr (Olsen & Sues, 1986). According to Beerling (2002a), depending on the proxy used, CO2 levels rising from the Rhaetian (~204 Ma) reached about ~1300–2200 ppm from leaf stomata, and a wider range from carbon isotopes, just above the RhaetianHettangian (early Jurassic) boundary, signifying an extreme greenhouse event of ~34% of genera.

7.5

Jurassic-Cretaceous Extinction

The Triassic-Jurassic boundary marks a major faunal mass extinction, but records of accompanying environmental changes are limited. Evidence across the boundary indicates a marked increase in atmospheric CO2 and associated temperature rise of about 3–4 °C. These environmental conditions are calculated to have raised leaf temperatures above a highly conserved lethal limit, perhaps contributing to the > 95% species-level turnover of Triassic-Jurassic megaflora (McElwain et al., 1999).

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7.6

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Phanerozoic Mass Extinctions

K-T (Cretaceous-Tertiary Boundary) Impact and Mass Extinction

The K-T boundary (64.98 ± 0.05 Ma) marks the second largest mass extinction of species recorded in Earth history, when some 46 per cent of living genera disappeared (Keller, 2005). Alvarez et al. (1980) documented the hiatus across the Cretaceous-Paleocene boundary in Italy, where a foraminifera-rich white limestone facies containing large-scale Globotruncana contusa is abruptly replaced by overlying clay-rich red limestone termed Scaglia rossa contain smaller foraminifera (Globigerina eugubina) and micron-scale algal coccoliths. At the classic locality at Gubbio (Fig. 7.2) a ~1 cm-thick boundary clay layer consists of a lower ~5 mmthick grey clay zone consists of clastic material and an upper ~5 mm- thick red clay zone termed ‘fire layer’. This layer contains an Iridium anomaly of up to ~9 ppb. Similar relations are observed elsewhere. The boundary coincides with a major geomagnetic reversal correlated with a marine magnetic anomaly sequence dated with foraminifera. The parent craters of the K-T event have been identified, including Chicxulub (170 km in diameter, Yucatan Peninsula, Mexico) and Boltysh (~25 km in diameter; 65.17 ± 0.64 Ma, Ukraine). Since the initial discovery of K-T impact ejecta, best preserved in deep water environment, 101 sites have been identified along the Maastrichtian–Danian boundary around the globe (Claeys et al., 2002). Around the Gulf of Mexico and the Atlantic Ocean the ejecta layer coincides with erosion of Maastrichtian sediments and is overlain by clastic sediments and breccia attributable to seismic and tsunami effects. A panel of 41 international experts from 33 institutions concluded the evidence for a cause and effect relation between asteroid impact and mass extinction at the K-T boundary is overwhelming (Schulte et al., 2010). The Chicxulub impact and Boltysh impacts occurred during an active volcanic period which saw continuing eruptions in the Deccan (northwest India) volcanic province recently dated by U–Pb ages (Schoene et al., 2015) to have commenced approximately ~250,000 years before the K-T boundary. The Deccan volcanism produced > 1.1 million km3 of basalt during ~750,000 years, inducing environmental changes preceding the terminal effects of the extraterrestrial bombardment. Stomata leaf pore-based estimates of atmospheric CO2 during these events indicate an abrupt rise from ~350–500 ppm to at least ~2300 ppm within about 10,000 years, consistent with instantaneous transfer of ~4600 Gigaton Carbon (GtC) to the atmospheric reservoir. Climate models suggest consequent forcing of 12 W/m2 , sufficient to warm the Earth’s surface by ~7.5 °C in the absence of counter forcing by sulphate aerosols. A CO2 rise of ~1800 ppm and temperature rise occurred over a period of ~10,000 years, namely at rates of ~0.18 ppm/year and 0.00075 °C/year. Notably these rates are lower than the Anthropocene rate, where current CO2 rise occurs at 2 to 3 ppm/year (NASA, Mouna Loa CO2 ). Short term effects of the K-T asteroid impact include incineration of large land surfaces from the heat pulse of the incoming projectile, from the explosion and settling of ejecta and microkrystite spherules (Wolbach et al., 1990), ejection of dust and water vapor and oxidation of atmospheric nitrogen and consequent

7.8 End-Eocene Freeze

53

ozone depletion. Longer term effects included release of CO2 and other greenhouse gases with consequent warming, ocean acidification and anoxia (Toon et al., 1997). The K-T mass extinction involved phytoplankton, calcareous nanoplankton, planktonic foraminifera, benthic foraminifera, 54% of diatoms, marine invertebrates, crustaceans, ostracods, 98% of tropical colonial corals, 60% of late Cretaceous Scleractinia coral, echinoderm, and bivalve genera, numerous species of the molluscan and Cephalopoda and all cephalopod species, belemnoids and ammonoids, 35% of echinoderm genera, rudists (reef-building clams), inoceramids (giant relatives of modern scallops), jawed fishes, cartilaginous fishes. Survivors included ~80% of the sharks, rays, and skates families. In North America, approximately 57% of plant species became extinct. All Archaic birds and non-avian dinosaurs became extinct. Cretaceous mammalian lineages, including egg-laying mammals, multi-tuberculates, marsupials and placentals, dryolestoideans, and gondwanatheres survived. Marsupials mostly disappeared from North America and Asian deltatheroidans became extinct. Many of these extinctions constituted proximal instantaneous consequences of the fire ball and asteroid explosion, while distal habitats were affected by more protracted consequences (Fig. 7.2).

7.7

Paleocene-Eocene Thermal Peak

The Paleocene-Eocene thermal maximum (PETM) at ~55.9 Ma involved a release of some ~2000 billion ton carbon (GtC) as methane, elevating atmospheric CO2 to near-1800 ppm at a rate of 0.18 ppm/year, and mean temperature rise of ~5 °C (Cui et al., 2011; Panchuk et al., 2008; Zachos et al., 2008). Elevated CO2 led to acidification of ocean water from ~8.2 to ~7.5 pH and the extinction of ~35–50% of benthic foraminifera during a period of ~1000 years (Zachos et al., 2008). Other consequences included a global expansion of subtropical dinoflagellate plankton and the appearance of modern orders of mammals, including primates, a transient dwarfing of mammalian species, and migration of large mammals from Asia to North America.

7.8

End-Eocene Freeze

The incidence of an asteroid impact cluster about 35.7–35.6 Ma (Popigai, Siberia ~100 km-diameter; Chesapeake Bay, off-shore Virginia—85 km-diameter; Mount Ashmore, Timor Sea—> 50 km-diameter; the related North American strewn tektite field) and the abrupt decline in temperatures about ~33.7–33.5 Ma triggered major environmental and biotic transformations. Abrupt cooling (Pearson et al., 2009) was associated with elimination of warm-water planktonic species (Keller, 1986) suggested stepwise extinctions during the late Eocene and the E-O transition. Keller (2005) suggested comet showers in the late Eocene. Isotopic δ13 C and δ18 O studies of late Eocene Iridium-rich ejecta layers at Massignano, Italy, indicate increase in temperature and in organic matter associated with impacts,

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Phanerozoic Mass Extinctions

Fig. 7.2 The K-T boundary in Wyoming, USA. Intermediate claystone layer contains 1000 times more iridium than the upper and lower layers. It is the boundary between Cretaceous and Tertiary Periods. Wikipedia commons (K-T boundary JPG)

possibly reflecting release of methane hydrates by impact excavation (Bodiselitsch et al., 2004; Monechi et al., 2000).

References Alvarez, L. W., et al. (1980). Extra-terrestrial cause for the cretaceous-tertiary extinction: Experimental results and theoretical interpretation. Science, 208, 1085–1095. Balter, V., et al. (2008). Record of climate-driven morphological changes in 376 Ma Devonian fossils. Geology, 36, 907. Beerling, D. J. (2002a). CO2 and the end-Triassic mass extinction. Nature, 415, 386–387. Beerling, D. J. (2002b). Low atmospheric CO2 levels during the Permo-Carboniferous glaciation inferred from fossil lycopsids. Proceedings of National Academy of Science, 99, 12567–12571.

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Beerling, D. J., et al. (2001). Evolution of leaf-form in land plants linked to atmospheric CO2 decline in the Late Palaeozoic era. Nature, 410, 352–354. Berner, R. A. (2005). The carbon and sulphur cycles and atmospheric oxygen from middle Permian to middle Triassic. Geochimica Et Cosmochimica Acta, 69, 3211–3217. Bodiselitsch, B., et al. (2004). Delayed climate cooling in the late Eocene caused by multiple impacts: High-resolution geochemical studies at Massignano, Italy Earth Planet. Science Letters, 223, 283–302. Brenchley, P. J. (2003). High-resolution isotope stratigraphy of late Ordovician sequences: Constraints on the timing of bio-events and environmental changes associated with mass extinction and glaciation. Geological Society of America Bulletin, 115, 89–104. Claeys, P., et al. (2002). Distribution of Chicxulub ejecta at the cretaceous-tertiary boundary. In Catastrophic events and mass extinctions: impacts and beyond, Geological Society of America, 356, 55–68. Courtillot, V. E., & Rennes, P. R. (2003). On the ages of flood basalt events. Comptes Rendus Geoscience, 335, 113–140. Cui, Y., et al. (2011). Slow release of fossil carbon during the Palaeocene–Eocene thermal maximum. National Geoscience, 4, 481–485. Eby, N., et al. (2009). Lifetime of anthropogenic climate change: Millennial time scales of potential CO2 and surface temperature perturbations. Journal of Climate, 22, 2501–2511. Frakes, L. A., et al. (1992). Climate modes of the Phanerozoic. Cambridge University Press. French, B. M. (1998). Traces of catastrophe (vol. 954, p. 120). Lunar Planetary Institute. Glikson, A. Y. (2005). Asteroid/comet impact clusters, flood basalts and mass extinctions: Significance of isotopic age overlaps. Earth and Planetary Science Letters, 236, 933–937. Glikson, A. Y., & Pirajno, F. (2018). Asteroids Impacts (p. 215). Springer. Glikson, A. Y., & Yeates, A. N. (2022). Geophysics and origin of the Deniliquin multiple-ring feature, Southeast Australia. Tectonophysics, 837, 229454. Glikson, A. Y. (2013). Existential risks to our planetary life-support systems. Published: September 5, 2013. Grasby, S. E., et al. (2011). Catastrophic dispersion of coal fly ash into oceans during the latest Permian extinction. Nature Geoscience, 4, 104–107. Hallam, A., & Wignall, P. B. (1997). Mass extinctions and their aftermath. Oxford University Press. Hames, W. (2003). The central Atlantic magmatic province: Insight from fragments of Pangea. Geophysics Monograph Series, 136, 267. Jourdan, F., et al. (2009). 40 Ar/39 Ar ages of CAMP in North America: Implications for the TriassicJurassic boundary and the 40 K decay constant bias. Lithos, 110, 167–180. Kamo, S. L. (2003). Rapid eruption of Siberian flood-volcanic rocks and evidence for coincidence with the Permian-Triassic boundary and mass extinction at 251 Ma. Earth Planetary Science Letter, 214, 75–91. Keller, G. (2005). Impacts volcanism and mass extinction: Random coincidence or cause and effect? Australian Journal of Earth Sciences, 52, 725–757. Keller, G. (1986). Stepwise mass extinctions and impact events; late Eocene to early Oligocene. Micropaleontology,10, 267–293. Kump, L. R., et al. (1999). A weathering hypothesis for glaciation at high atmospheric pCO2 during the late Ordovician. Palaeoclimatology Palaeogeography Palaeoecology, 152, 173–187. Marshall, J. D. (1992). Climatic and oceanographic isotopic signals from the carbonate rock record and their preservation. Geological Magazine, 129, 143–160. Marshall, J. D., et al. (1997). Global carbon isotopic events associated with mass extinction and glaciation in the late Ordovician. Palaeogeography, Palaeoclimatology, Palaeoecology, 132, 195–210. Maruoka, T., et al. (2007). Carbon isotopic compositions of organic matter across continental Cretaceous-tertiary (K-T) boundary sections: Implications for paleoenvironment after the K-T impact event. Earth and Planetary Science Letters, 253, 226–238. McElwain, J. C., & Punyasena, S. W. (2007). Mass extinction events and the plant fossil record. Trends in Ecology & Evolution, 22, 549–557.

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McElwain, J. C., et al. (1999). Fossil plants and global warming at the Triassic-Jurassic boundary. Science, 285, 1386–1390. McGhee, G. R. (1996). The late Devonian mass extinction. Columbia University Press. Monechi, S., et al. (2000). Biotic signals from nannofl ora across the iridium anomaly in the upper Eocene of the Massignano section: Evidence from statistical analysis. Micropaleontology, 39, 219–237. Mora, C. I., et al. (1996). Middle to late Paleozoic atmospheric CO2 levels from soil carbonate and organic matter. Science, 27, 1105–1107. Olsen, P. E., & Sues, H. D. (1986). Correlation of continental late Triassic and early Jurassic sediments and patterns of the Triassic-Jurassic tetrapod transition. In K. Padian (Ed.), The beginning of the age of dinosaurs (pp. 321–351). Cambridge University Press. Panchuk, K., et al. (2008). Sedimentary response to Paleocene-Eocene thermal maximum carbon release: A model-data comparison. Geology, 36, 315–318. Pearson, P. N. (2009). Atmospheric carbon dioxide through the Eocene-Oligocene climate transition. Nature, 461, 1110–1113. Pilkington, M., & Grieve, R. A. F. (1992). The geophysical signature of terrestrial impact craters. Reviews of Geophysics, 30(2), 161–181. Pope, K. O., et al. (1997). Energy volatile production and climatic effects of the Chicxulub Cretaceous/tertiary impact. Journal of Geophysical Research, 102, 21645–21664. Racki, G. (2003). End-Permian mass extinction: Oceanographic consequences of double catastrophic volcanism. Lethaia, 36, 171–173. Renne, P. R., et al. (1995). Synchrony and causal relations between Permian—Triassic boundary crises and Siberian flood volcanism. Science, 269, 1413–1416. Ross, C. A., & Ross, R. P., et al. (1995). Permian sequence stratigraphy. In P. A. Scholle (Ed.), The Permian of northern Pangea (Vol. 1, pp. 98–123). Springer. Rothwell, G. W. (1989). Elkinsia gennov a Late Devonian gymnosperm with cupulate ovules. Botanical Gazette, 150, 170–189. Royer, D. L. (2006). CO2 -forced climate thresholds during the Phanerozoic. Geochimica Et Cosmochimica Acta, 70, 5665–5675. Schoene, B., et al. (2015). U–Pb geochronology of the Deccan traps and relation to the endcretaceous mass extinction. Science, 347(6218), 182–184. Schulte, P., et al. (2010). The Chicxulub asteroid impact and mass extinction at the CretaceousPaleogene boundary. Science, 327(5970), 1214–1218. Solomon, S., et al. (2009). Irreversible climate change due to carbon dioxide emissions. Proceedings of the National Academy of Sciences of the United States of America, 106, 1704–1709. Tohver, E., et al. (2012). Geochronological constraints on the age of a Permo-Triassic impact event: U-Pb and 40 Ar/39 Ar results for the 40 km Araguainha structure of central Brazil. Geochimica et Cosmochimica. Acta, 86, 214–227. Toon, O. B., et al. (1997). Environmental perturbations caused by the impacts of asteroids and comets. Reviews of Geophysics, 35, 41–78. Twitchett, R. J. (2001). Rapid and synchronous collapse of marine and terrestrial ecosystems during the end-Permian crisis. Geology, 29, 351–354. Ward, P. D. (2007). Under a green sky: Global warming, the mass extinctions of the past, and what they can tell us about our future (p. 242). Harper Collins. Whiteside, J. H., et al. (2010). Compound-specific carbon isotopes from earth’s largest flood basalt eruptions directly linked to the end-Triassic mass extinction. Proceedings of the National Academy of Sciences of the United States of America, 107(15), 6721–6725. Wignall, P. B. (2001). Large igneous provinces and mass extinctions. Earth-Science Reviews, 53, 1–33. Wignall, P. B., & Twitchett, R. J. (1996). Oceanic anoxia and the end Permian mass extinction. Science, 272, 1155–1158. Wolbach, S. W., et al. (1990). Is the soot layer at the KT boundary really global? Lunar and Planetary Science, XXIX, 1309.

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Yeates, A. N., et al. (2000). An interpreted approximately 1240 km-diameter multiple-ring structure, of possible impact origin, centred beneath the Deniliquin region, south-eastern Australia. In D. Denham (Ed.), Exploration beyond 2000, 81–82. Conference handbook, Aust. Soc. Explor. Geophys., Preview, p. 84. Zachos, J., et al. (2008). An early Cenozoic perspective on greenhouse warming nd carbon-cycle dynamics. Nature, 451, 279–283.

8

The Holocene

8.1

The Younger Dryas

Abrupt climate shifts including stadial cooling during the interglacials are exemplified by the onset and termination of the 12.9–11.7 kyr Younger Dryas cold phase over transitions as short as 1–3 years (Steffensen et al., 2008), including a sharp temperature decline of several degrees Celsius in the North Atlantic associated with discharge of cold water from the Laurentian ice sheet. In the wake of the last deglaciation peak pre-Holocene temperatures are represented by the 14.7–12.9 kyr Bolling-Alerod interstadial, preceded by a cool ‘Older dryas’ phase (Fig. 8.1). The Younger dryas was succeeded by the Holocene Optimum (Shakun et al., 2012; Steffensen et al., 2008). Peak early Holocene conditions involved heavy precipitation and (Clift et al., 2007), perhaps echoed by Noah’s Ark story. At ~8.2 kyr a sharp stadial involving temperature decline of several degrees Celsius in the North Atlantic was associated with discharge of cold water from the Laurentian ice sheet through Lake Agassiz (Wagner et al., 2013; Wiersma et al., 2011). High temperatures during the Holocene maximum resulted in strong East African monsoons and higher rainfall in the Sahara relative to previous and succeeding periods, which explains the presence of animals like giraffes and gazelle recorded in ancient rock paintings. Consequently cooler and drier conditions ensued with temperature decline in the range of − 1 to – 5 °C in mid-latitudes and of − 3 °C measured in from ancient coral reef in Indonesia. Atmospheric CO2 declined by ~25 ppm over ~300 years. About 8.2 kyr the earliest settled human communities in Catal Huyuk (southern Anatolia) were abandoned, likely due to droughts associated with the cooling, and were not reoccupied until about five centuries later when climate improved. The Younger dryas cooling interval is highly significant for the current anthropogenic warming which is already showing signs of brief cooling intervals (Fig. 13.3).

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 A. Y. Glikson, The Trials of Gaia, https://doi.org/10.1007/978-3-031-23709-6_8

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Fig. 8.1 Evolution of temperature in the glacial and post-glacial periods documented by Greenland ice cores. Wikipedia commons

8.2

The Neolithic

Based on DNA analysis chimpanzees are human’s closest biological relatives, followed by gorillas, orangutans, gibbons and monkeys. From molecular clock calculations human and chimpanzee lineages diverged from a common ancestor about 6 million years ago. The capability of advanced apes to use tools, including wood tools for digging, grass stems for termite collection, sponges to get water from tree holes, stones to crack nuts, and to collaborate in planning search for food. In the wake of the deepest glacial interval between the Eemian (130–115 kyr) and the Holocene (11,650 years—present) the last deglaciation (~14.7–12.9 kyr), followed by abrupt events including the Bølling-Alerød interstadial (14,690 to 12,890 years), a cool ‘Older Dryas’ stadial phase and sharp cooling at the ‘Younger Dryas’ (12.9–11.7 kyr) was succeeded by the Holocene Optimum (Shakun et al., 2012; Steffensen et al., 2008) (Fig. 8.1). Peak early Holocene conditions included heavy precipitation and thereby rates of erosion (Clift et al., 2007), perhaps echoed by Noah’s Ark legend. About ~8.2 kyr a sharp temperature decline in the North Atlantic was associated with discharge of cold water from the Laurentian ice sheet through Lake Agassiz (Wagner et al., 2013; Wiersma et al., 2011). High temperatures during the Holocene maximum resulted in strong East African monsoons and higher rainfall in the Sahara relative to previous and succeeding periods, which explains the presence of animals like giraffes and elephants recorded in ancient rock paintings. Subsequently cooler and drier conditions ensued with temperature decline in mid-latitudes.

8.2 The Neolithic

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About 8.2 kyr the earliest settled human communities in Catal Huyuk, southern Anatolia, were abandoned, likely due to droughts associated with the cooling, and were not reoccupied until about five centuries later when climate improved. A decline in CO2 and methane following the Holocene Optimum at ~8–6 kyr was followed by a slow rise in CO2 from ~6000 BP and methane from ~4000 BP. According to Ruddiman (2003) the natural interglacial cycle has been overprinted by Neolithic burning and land clearing, halting a decline in CO2 and methane and thereby preventing an onset of the next glacial (Kutzbach et al., 2010). Other authors regard the mid-Holocene rise in greenhouse gases as a natural perturbation in the interglacial, comparable with features of the 420–405 kyr Holsteinian interglacial (Broecker & Stocker, 2006). The late Holocene is interrupted by mild warming phase ~900–1400 AD years-ago (Medieval Warm Period) and a cool phase during ~1550–1800 AD (Little Ice Age), broadly corresponding to periods of solar insolation reaching + 0.5 W/m2 and − 0.5 W/m2 relative to pre-industrial levels,respectively, attributed in part to changes in insolation related to sunspot activity (Solanki, 2002) and volcanic eruptions in Iceland. In the wake of climate disruptions associated with the last glacial termination about ~14–7.5 kyr ago, the climate stabilized between ~7 and 5 kyr when sea level reached a maximum. Of all the factors which underlie the rise and fall of ancient civilizations along the Nile, Tigris, Euphrates, Indus and the Yellow River valleys, the main control was exerted by the seasonally regulated balance in their mountain river source regions between accumulation and melting of snow. Thus cold spells would decrease river flow, resulting in droughts, whereas strong monsoons result in floods and erosion of terraces. Under stable rhythmic climate, seasonal regulation of river flow accompanied by deposition of fertile silt allowed river terrace cultivation, providing food for villages, towns and subsequently kingdoms and empires. The Nile River, fed by water sourced in the Ethiopian Mountains, allowed the flourishing of the Old Kingdom (4660–4160 BP), Middle Kingdom (4040–3640 BP) and the New Kingdom (3550–3070 BP). The largest pyramids were built during the Old Kingdom. The greatest expansion of the Pharaoh’s territories in the Middle East occurred during the New Kingdom. Stages in the history of the Nile River included: • ~20–12.5 kyr—Northeast Africa—frozen Ethiopian Mountains; stable sediment alluviation and terrace building by a low-flow river; Hunter-gatherers. • ~12.5–8 kyr—Northeast Africa—high floods (the ‘wild Nile’) due to heavy rains in the Ethiopian Highlands; little rain along the Nile. Increased vegetation at the source leads to less sedimentation and thus greater erosion of river terraces; near-disappearance of population. • ~8–6 kyr—Seasonal climate, stabilization of the Nile and re-aggradation of alluvial terraces, allowing irrigated agriculture. • ~7.5–5.1 kyr pre-dynastic Egypt. • ~5.5 kyr—Retreat of the rain belt southward. • ~4.686–4.181 kyr—Old Kingdom. • ~4.2–4.0 kyr—Desertification.

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• ~4.0–3.7 kyr—Middle Kingdom. • ~3.570–3.069 kyr—New Kingdom • ~3.2–2.55 kyr—Iron Age cold period. The ~ 4.1 kyr desertification constituted one of the most severe climatic events of the Holocene, in terms of its impact on civilization. It is thought that at this stage the White Nile ceased to flow continuously and this is likely to have caused the collapse of the Old Kingdom in Egypt, the Akkadian Empire in Mesopotamia, and the Indus Harappan cultural domain. Radiocarbon age determination from Tell Leilan (Fig. 8.3), northeast Syria, uncovers evidence for an incipient collapse of the Akkadian empire near 4170 ± 150 BP (Weiss et al., 1993). Deep sea core sediments from the Gulf of Oman testify to a several-fold increase in wind-borne aeolian components from 4025 ± 125 BP, representing development of arid conditions in the source regions of the dust in Mesopotamia (Cullen et al., 2000). The Tigris and Euphrates rivers, fed by the waters from the Taurus Mountains, constitute the cradle of the Mesopotamian (“Land between the rivers”) civilization, where irrigation developed from about 6000 BP and Sumer cities grew between 3200 and 2350 BP, succeeded by Babylon. The Harappan civilization was developed by Dravidians people along the Indus River, fed from the Himalaya. Cultivation along the Yellow and Yangzi Rivers including the Xia, Shang and the Zhou Dynasties developed from about 7000 BP. According to deMenocal (2001) late Holocene climate perturbations included repeated inter-annual droughts and infrequent decadal droughts. Multi-decade-long to multi-century-long droughts were rare but formed integral components of the natural climate variability. Paleoclimate and archaeological records demonstrate close relations between prolonged droughts and social collapse. Overpopulation, deforestation, resource depletion and warfare reinforced social collapse. Repeated droughts likely constituted the root factors in the downfall of the Acadian, Maya, Mochica and Tiwanaku civilizations (Shen, 2012). A dry period in central America during 530–650 AD, followed by droughts during 800–1000 AD, recorded by high gypsum precipitation and high δ18 O in lake sediments (Lakes Chichancanab and Punta Laguna), leading to collapse of the Maya civilization between 750 and 790 AD. The last Maya monument was constructed in 990 AD (deMenocal, 2001). Further confirmation of these trends is based on a paleoclimate study of Balum Cave deposits, Belize, correlated with dated Maya stone monuments (Shen, 2012). The study indicates a high rainfall period during 440–660 AD followed by a drying trend between 660 and 1000 AD, leading to collapse between 1020 and 1100 AD. A decrease in temperatures during 600–1000 AD is also recorded in the Quelccaya ice cores in Peru, showing an increase in the accumulation of ice and dust particles, signifying colder climate and a decrease in precipitation which affected the Tiwanaku civilization (300–1100 AD), leading to collapse between 1100 and 1400 AD. Based on the study of tree rings, during the fourteenth and fifteenth centuries, the Khmer Empire in Cambodia experienced decades-long droughts induced by strong El Nino events, interspersed with intense monsoons. Increased climate

8.3 The 4200 Years-Old Mega-Drought

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variability, which damaged water supply dams and canals on which the Angkor Watt depended, led to the demise of Khmer civilization. The end of the 1st millennium and the first half of the 2nd millennium constituted the Medieval Warm Period (MWP—900–1200 AD), which was about + 0.4 °C warmer than the period ~1500–1900 AD. The coolest century was the 17th (− 0.4 °C relative to preindustrial temperatures), including the Little Ice Age ~1600–1700 AD related to a near-absence of sun spots (Jones, 2001; Solanki, 2002) and volcanic eruptions in Iceland. Multi-proxy temperature reconstructions for the northern hemisphere show that the recent 30-year period is likely to have been the warmest of the millennium (Jones, 2001). Southern Hemisphere temperature reconstructions indicate cooler conditions before 1900 but the data are less reliable than northern hemisphere data. From the above, civilizations depended critically on specific climate conditions and collapsed to a large extent due to natural climate variability which led to economic and social crises, decline in population and war (Diamond, 2005). Collapse may have occurred intermittently, as in Egypt and China, or become terminal as in Easter Island.

8.3

The 4200 Years-Old Mega-Drought

The 4.3–3.8 kyr BP collapse of Early Bronze Age civilizations coincident with extensive Middle East aridity, termed as the Meghalayan, uppermost stage of the Quaternary. The Megahalayan persisted for several decades, as testified by speleothems (Fig. 8.2) from Sofular and Ovacik caves in northwestern Turkey, Qunf Cave in Oman and Mawmluh Cave, northeast India. U-series and U-Th dates combined with stable isotope analyses allow resolutions within errors of ~0.8 ~2.5 and ~4 years (Jones et al., 2016). The ~4.0 kyr BP collapse of the Akkadian civilization coincided with reduction in the Indian Ocean Monsoon precipitation. Archaeological evidence for decline of civilizations abounds, with the classic case being the Tell Leilan in northeastern Syria (Weiss, 1985) (Fig. 8.3). The Mediterranean region and the Levant have returned some of the clearest evidence of a climatically dry period occurring around 4200 years ago (Bini et al., 2019). Evidence from proxies of sea-surface temperature, precipitation, and temperature from pollen, δ18 O on speleothems, and δ18 O on lacustrine carbonate over the Mediterranean Basin suggest with some exceptions dry winters, dry summers and cooling anomalies. Some views of the Meghalayan suggest the event was not global but consisted of a series of droughts including climate shifts in some regions.

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Fig. 8.2 This stalagmite from Mawmluh Cave in northeastern India formed in layers over the course of thousands of years. It holds evidence of a sharp drop in precipitation in the region around 4200 years ago. Credit: Ashish Sinha. Permission: Springer/Nature

Fig. 8.3 The Tel Leilan excavations. Northeastern Syria. Credit: H. Weiss/Yale University. Springer/Nature

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References Bini, M., et al. (2019). The 4.2 ka BP event in the Mediterranean region: An overview. The Climate of the Past, 15, 555–577. Broecker, W. C., & Stocker, T. F. (2006). The Holocene CO2 rise: Anthropogenic or natural? Eos, 87, 27–29. Clift, P. D., et al. (2007). Holocene erosion of the lesser Himalaya triggered by intensified summer monsoon. Geology, 36, 79–82. Cullen, H. M. (2000). Climate change and the collapse of the Akkadian empire: Evidence from the deep sea. Geology, 28, 379–382. deMenocal, P. B. (2001). Cultural responses to climate change during the late Holocene. Science, 292, 667–673. Diamond, J. (2005). Collapse: How societies choose to fail or succeed (576 pp). Penguin Group. Jones, H. P. (2001). Comparison of total solar irradiance with NASA/National solar observatory spectro-magnetograph data in solar cycles 22 and 23. Jones, S., et al. (2016). A critical evaluation of the 4.2 ka BP event using new high resolution evidence from stalagmites in the Middle East. EGU General Assembly 17–22 April, Vienna, Austria. Kutzbach, J. E. (2010). Climate model simulation of anthropogenic influence on greenhouseinduced climate change (early agriculture to modern): The role of ocean feedbacks. Climatic Change, 99, 351–381. Ruddiman, W. F. (2003). Orbital insolation, ice volume, and greenhouse gases. Quaternary Science Reviews, 22, 1597–1629. Shakun, J. D., et al. (2012). Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation. Nature, 484, 49–55. Shen, H. (2012). Drought-hastened Maya decline: a prolonged dry period contributed to civilization collapse. Nature, 8/11/2012. Solanki, S. K. (2002). Solar variability and climate change: Is there a link? Astronomy & Geophysics, 43(5). Steffensen, J. P., et al. (2008). High-resolution Greenland ice core data show abrupt climate change happens in few years. Science, 321, 680–684. Wagner, A. J., et al. (2013). Model support for forcing of the 8.2 ka event by melt water from the Hudson Bay ice dome. Climate Dynamics, 41, 2855–2873. Weiss, H. (1985). Excavations at Tell Leilan, Syria. American Journal of Archaeology, 94(4). Weiss, H. (1993). The genesis and collapse of third millennium north Mesopotamian civilization. Science, 261(5124), 995–1004 Wiersma, A. P., et al. (2011). Fingerprinting the 8.2 ka event climate response in a coupled climate model. Journal of Quarternary Science, 26, 118–125.

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9.1

Carbon Emission and Climate Disruption

Since 1750 the world has emitted over 1.5 trillion (1.5.1012 ) tonnes of CO2 (Ritchie and Roser, 2016) with consequent rise in temperatures at extreme rates (Fig. 9.1a), high warming projections (Fig. 9.1b) and anomalous heat waves (Figs. 9.1c; 9.3), consequent on the release of carbon dioxide from deforestation, animal husbandry combustion of coal, oil, gas, and cement (Fig. 9.2). With greenhouse gases in May 2022 reaching a level of 421 parts per million (ppm) CO2 at Mouna Loa, growing at unprecedented rates of 2.0–3.0 ppm/year (Fig. 9.1a), to date the fastest acceleration of atmospheric greenhouse gases and of temperatures was reached since the mass extinction of the dinosaur ~66 million years ago. Cumulative atmospheric CO2 levels are triggering self-amplifying feedback effects, including enhanced evaporation, fires, cyclones, storms, ice melt and methane emissions from permafrost and sediments. Whereas according to the head of the International Energy Agency no new oil, gas or coal development ought to take place if the world is to reach net zero by 2050, rising production of hydrocarbons in several regions, for example new drilling for oil in the North Sea, high production of oil and gas the USA, new coal mines and gas wells in Australia and elsewhere, cast doubt on the future level of carbon emissions. Given the abrupt change in state of the atmosphere-ocean-cryosphere-land system, accelerating since the mid-20th century, the terms “climate change” and “global warming” no longer convey the extreme nature of the atmospheric event consequent on this shift (Fig. 9.3). Further to NASA’s reported mean land-ocean temperature rise to 1.1 °C since 1880, where large parts of the continents, including Siberia, central Asia, Canada, parts of west Africa, eastern South America and Australia are warming toward mean temperatures of + 2.0 °C relative to the onset of the 20th century and higher, as manifested by heat waves (Fig. 9.3). The warming rate of 0.15 to 0.20 °C per decade exceeds that of the Last Glacial Termination © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 A. Y. Glikson, The Trials of Gaia, https://doi.org/10.1007/978-3-031-23709-6_9

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(a)

(b)

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Fig. 9.1 a Global average surface temperatures relative to the 1950–1980 baseline (NASA), b IPCC model SPM.5. Temperature projections for the twenty-first century according to a number of models. Solid lines are multi-model global surface warming averages (relative to 1980–1999) for scenarios A2, A1B and B1, shown as continuations of the twentieth century. Permission from IPCC granted for use the material exactly as it is in the report, c global temperature anomaly distribution: The frequency of occurrence (vertical axis) of local temperature anomalies (relative to 1951–1980 mean) in units of local standard deviation (horizontal axis). Area under each curve is unity. Image credit: NASA/GISS

(LGT) (17-10 kyr), the Paleocene-Eocene hyperthermal event (PETM) (55.9 Ma) and the Cretaceous-Tertiary boundary (K-T) (64.98 Ma) impact event. This rate is reflected by current migration rate of the northern climate zones toward the pole of ~0.5° of latitude per decade since 1979 (Staten et al., 2018). Significant transient

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Fig. 9.2 a Annual mean carbon dioxide growth rates for NASA Mauna Loa, b global CO2 emissions by fuel (Global Carbon Project)

cooling intervals, or stadials, are projected as a consequence of the flow of cold ice melt from Greenland and Antarctica into the oceans (Hansen et al., 2016). In Australia climate change has contributed to a southward shift in weather systems that typically bring cool season rainfall to southern Australia. As the cold humid spirals of the Antarctic vortex recede to the south since the 1970s late autumn and early winter rainfall has decreased by 15% in southeast Australia and Western Australia’s southwest region. Current drought conditions come after a

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Fig. 9.3 Extreme heatwaves, like the one that affected Europe in the summer of 2006, are projected to become widespread at 1.5 °C warming relative to the onset of the 20th century. This map, derived from NASA Modis Terra satellite data, depicts the July 2006 land surface temperature anomaly with regard to the period from 2000 to 2012. Permission NASA

2016/2017 and 2018 summer characterized by record-breaking temperatures, followed by a record dry winter. Rainfall over southern Australia during autumn 2018 was the second lowest on record. The drought has reached extreme level, accompanied by wildfires. Australia, like other parts of the world, is paying the price of climate change in terms of growing damage to its agriculture, communities and way of life. Many climate change models, including by the IPCC, appear to minimize or even neglect the intensifying feedbacks to global warming, which are pushing temperatures upward in a runaway chain reaction-like process. As projected by Wally Broecker, who stated (Krajick, 2019): “The paleoclimate record shouts to us that, far from being self-stabilizing, the Earth’s climate system is an ornery beast which overreacts even to small nudges”. These feedbacks drive a chain reaction of events, accelerating the warming, as follows: (1) Melting snow and ice expose dark rock surfaces, reducing the albedo of the polar terrains and sea ice in surrounding

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oceans, enhancing infrared absorption and heating; (2) Fires create charred lowalbedo land surfaces; (3) An increase in evaporation raises atmospheric vapour levels, enhancing the greenhouse gas effect; (4) Whereas an increase in plant leaf area enhances photosynthesis and evaporation creating a cooling effect, the reduction in vegetation in darkened logged and burnt areas works in the opposite direction, warming land surfaces. The current acceleration of global warming is reflected by the anomalous rise of temperatures, in particular during 2010–2020 (Hansen, 2021). Consequently, extensive regions are burning, with 4 to 5 million fires per year counted between about 2004 and 2019 (Collins et al., 2021). In 2021, global April temperatures have been lower than in 2020, due to moderately strong La Nina effects (Hansen et al., 2022). The triggering of a mass extinction event by the activity of organisms is not unique to the Anthropocene. The end-Permian mass extinction, the greatest calamity for life in geologic history, is marked in marine carbonates by a negative δ13 C shift attributed to oceanic anoxia and the emission of methane (CH4 ) and hydrogen sulphide (H2 S), related to the activity of methanogenic algae (“purple” and “green” bacteria) (Kump, 2011; Ward, 2006). As a corollary anthropogenic climate change constitutes a geological/biological process where the originating species, Homo sapiens, has not to date discovered an effective method of controlling the calamitous processes it has triggered. Unfortunately humans appear to be mostly concerned with any one issue at a time, and while COVID-19 is claiming the lives of millions, Homo sapiens appears to be increasingly oblivious to the growing threat to billions of humans (Xu et al., 2020) and to nature, including the inhabitability of large regions and habitats. The almost universal assumption as if a reduction in greenhouse gas emissions can by itself be sufficient to prevent further warming is in error, since positive feedbacks (Lashof, 2020) from land and ocean would continue to raise greenhouse levels and temperatures. With the current global atmospheric conditions rising toward Miocene levels (Fig. 9.4a), as CO2 level reach 420.99 ppm (Fig. 9.4b) within the range of Miocene CO2 levels of 400–500 ppm (Fig. 9.4a), the atmosphere is tracking toward supertropical temperatures, likely to render large regions uninhabitable toward later in the twenty-first century. At > 4 °C of warming above pre-industrial temperatures and higher (Fig. 9.5), the Earth’s mean surface land/ocean temperature would be nearly as warm as tropical Miocene temperatures. A lag effect between the rise of greenhouse gases and temperature and the effects of cold water flowing from melting ice sheets of Greenland and Antarctica would delay the worst effects of global warming, while storminess would increase due to collisions between tropical and polar air and water masses (Glikson, 2019a). Even before such high mean temperatures is reached, the weakened jet stream climate zone boundary, allowing penetration of cold and warm fronts, allowing clashes between air and water masses of contrasting temperatures, would lead to storminess, disrupting human agriculture and habitats, as already happening in northern Europe and within the Arctic circle.

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(a)

(b)

(c)

Fig. 9.4 a Analogy between the Miocene and projected Anthropocene temperatures. By Burke et al. (2019). b Comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. Credit: NASA

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Fig. 9.5 Global distribution of warming under a 4 °C temperature rise, as projected by the IPCC RCP8.5 model. Source Knutti and Sedlacek (2012), Carbonbrief

How long would it take for global temperatures to rise to about ~4 °C above pre-industrial level and higher would depend on: (1) The acceleration in rising concentration of greenhouse gases and amplifying feedbacks; (2) The lag in consequent rising temperatures; (3) The extent to which ice melt flow from Greenland and Antarctica may slow down further warming in certain regions, such as the north Atlantic and the Southern Ocean; (4) Further anthropogenic rise or decline of emissions and/or draw-down of atmospheric CO2 . According to the IPCC “the effects of +1.5 °C of warming (relative to mean preindustrial temperature), plus the projection that half a degree Celsius, 2 °C versus 1.5 °C, will make quite a considerable difference in the livability of planet Earth … the trajectory of warming based on historical trends will see increases certainly

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above 3 °C and possibly much more if emissions aren’t cut … the whole world must become carbon neutral by 2050.” The rise of atmospheric greenhouse gases to levels >> 400 ppm has the potential to rapidly transform the atmosphere into conditions similar to those of the Miocene and even the Eocene (Fig. 9.4a). As stated by the World Meteorological Organization: “The last time the Earth experienced a comparable concentration of CO2 was 3–5 million years ago, when the temperature was 2–3 °C warmer and sea level was 10–20 m higher than now”. Averages may be misleading. According to NASA, “The impacts of climate change haven’t been spread evenly around our planet … The strongest warming is happening in the Arctic during its cool seasons, and in Earth’s mid-latitude regions during the warm season”. The reduced albedo of the melting polar ice sheets are driving global warming at a rate faster than elevated temperatures in the tropics. While the focus of international policies is on the essential reduction in emissions, it is the cumulative effect of greenhouse gases in the atmosphere which drives global warming, the CO2 level in 2021 being 413.30 ppm, exceeding pre-industrial levels by more than 133 ppm. Unless civilization finds a way to down-draw CO2 from the atmosphere, amplifying feedbacks from land and oceans are bound to continue to heat the Earth. An essential point often missed in climate negotiations is that, due to the amplifying feedbacks of global warming, pushing temperatures up in a chain reaction-like process (Glikson, 2021) sequestration of CO2 is essential. Whereas the aim of the COP climate conferences is to reach agreement for limiting mean global temperature to arbitrarily determined levels, such as 1.5 or 2.0 °C, the short-term mitigating effect of aerosols on global temperatures, in the approximate range of − 0.5 to − 1.0 °C, implies mean global temperatures are already nearing ~2.0 °C. Since the Paris climate conference in April 2016, when the mean atmospheric carbon dioxide level reached 403.3 ppm, induced by annual emissions of some 400 billion tons of CO2 , the atmospheric level has risen to near 420 ppm, growing at peak rates of 2.5–3.0 ppm/year, the highest recorded since the dinosaur mass extinction of 66 million years ago. What could help saving the world from a climate catastrophe would depend on: (1) Binding agreements for the most abrupt reduction of carbon emissions rates to pre-peak rates of about 1 ppm/year or lower, requiring a world-wide transformation of agricultural, industrial and transport systems; (2) Attempts at sequestration/drawdown of greenhouse gases aimed at reducing the current atmospheric CO2 levels to near-350 ppm or lower (Hansen et al., 2013). Whereas the engineering efforts and costs of such attempts cannot be overestimated, such could in principle be achieved by diversion from the astronomical budgets invested in the “defence” industries aimed at future wars and further catastrophe. The concept of a “carbon budget”, allowing the world to constrain emission to a particular amount of greenhouse gases in order to limit warming, does not take into account the amplifying feedbacks to warming from land and oceans, nor possible reversals due to the flow of cold water from melting ice sheets into the oceans (Bronselaer et al., 2018). The critical criterion definitive of global warming, namely the atmospheric concentration of greenhouse gases, rising by nearly ~50%

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since pre-industrial time, is only rarely mentioned in the media or by politicians. Nor are other quantitative measures of climate change, such as the level methane and nitrous oxide, which have risen by about 3-fold being highlighted. International conferences have been unable to slow down exploration and development of hydrocarbon reserves (Fig. 9.2b) and a reduction in atmospheric CO2 . Since the Paris agreement in 2015, the world’s 60 largest banks have poured $3.8 trillion into fossil fuel companies. In the US, auctioning has begun of drilling rights in Alaskan waters and the Gulf of Mexico. In the UK, whose PM is talking about “one minute to midnight” (Rowlatt, 2021) 113 new licenses are offered to explore offshore reserves. Germany is developing new coal deposits. Australia, accounting for about 29% of traded coal globally in 2016, has become the world’s largest coal exporter and near-largest natural gas (LNG) exporter, currently representing around 3.6% of global emissions. Huge LNG projects were planned in 2020 in Alaska ($43 billion), Mozambique ($33 billion), Kuwait ($16 billion), Nigeria ($11 billion), Australia ($11 billion), Russia ($10.8 billion, pipeline), Louisiana ($10.8 billion), Greece ($5.5 billion, pipeline) and elsewhere. According to Nes-Fircroft “In terms of new projects, however, the outlook is wide open. According to sector research firm Rystad Energy, around 250 new Oil and Gas projects are likely to be sanctioned for development in 2020—up from 160 in 2016. The number of floating production, storage and offloading vessels (FPSOs) is due to increase with as many as 28 times. In India forecasts for 2024–2025 include utilization of energy supplies of 50% coal, 25% oil, 20% gas, 3% nuclear and 2% hydro. During the 20th century the global rise rate in CO2 has reached 2 to 3 ppm/year, the fastest recorded rate since 66 million years ago, while the level of CO2 equivalent (including the radiative forcing of methane and nitrous oxide) has risen above 500 ppm. According to the International Monetary Fund (IMF) (2017), the world is subsidizing fossil fuels by $5.2 trillion (Coady et al., 2019) equal to roughly 6.5% of global GDP, defining the extent to which the world is subsidizing its own demise. The loss of wealth due to reduced agricultural productivity owing to climate change is projected to exceed $19 billion by 2030, $211 billion by 2050 and a projected $4 trillion by 2100. A 2014 analysis concluded that fossil fuels drilled in the Arctic are expected to continue supplying much of the energy used worldwide. Since past, current and future emissions (Fig. 9.2) are bound to lead to growth in the cumulative levels of greenhouse gases in the atmosphere, the lack of effective methods of reducing their concentrations can only lead to catastrophic consequences. Unless civilization moves to a war-like footing, such as in the eve of world war II, in an attempt to reduce emissions from all sectors and sequester greenhouse gas levels, large parts of the Earth may become uninhabitable (Wallace-Wells, 2017). It is the children, led by Great Thunberg, an 18 years-old girl (Kraemer, 2021) who appear to have the perspective on what will determine the future of humanity and nature (Fig. 9.7). During the last and present centuries, global methane concentrations have risen from approximately ~700 parts per billion (ppb) to near-1900 ppb, the highest

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rate since the ice ages of the last 800,000 years. Methane (CH4 ), a powerful greenhouse gas ~80 times the radiative power of carbon dioxide (CO2 ) (Heilig, 1994) sourced from anaerobic decomposition in wetlands, rice fields, emission from animals, fermentation, animal waste, biomass burning, charcoal combustion and anaerobic decomposition of organic waste, is enriched by melting of leaking permafrost, leaks from sediments of the continental shelf and extraction as coal seam gas (CSG). Northern permafrost region soils contain 1460–1600 billion metric tons of organic carbon (Schuur, 2019), about twice as much as currently contained in the atmosphere. The addition to the atmosphere of even a part of this amount from Arctic permafrost would destine the Earth to temperatures higher than 4 °C above pre-industrial level and thereby the demise of the biosphere life support systems. The level of atmospheric methane, a toxic gas regarded as responsible for major mass extinction events in the past, has nearly tripled from ~722 ppb (parts per billion) to above ~1866 ppb during the 20–21st centuries, and is currently reinforced by coal seam gas (CSG) (Fig. 9.6) emissions. As the concentration of atmospheric methane from thawing Arctic permafrost (Struzik, 2020), from Arctic sediments and from marshlands worldwide is rising. Australia, possessing an abundance of natural gas (Murphy & Karp, 2021) is on track to become the world’s largest exporter. Leaks from hydraulic fracturing (fracking), production wells, transport and residues of combustion will contribute significantly to atmospheric methane (Turrentine, 2019). However, despite economic objections based on the availability of cheap alternative energy, natural gas from coal seam gas, liquefied to – 161 °C, is favored by governments (Morton, 2020) for domestic use as well as exports around the world. Serious climate and health risks are involved. In the Hunter Valley, NSW, the release of methane from open-cut coal mining reached above 3000 ppb. In the US methane released in some coal seam gas fields constitutes between 2 and 17% of emissions. While natural gas typically emits between 50 and 60% less CO2 than coal when burned, the drilling and extraction of natural gas from wells, fugitive emissions, leaks from transportation in pipelines result in enrichment of the atmosphere in methane. Methane, the main component of natural gas, 34 times stronger than CO2 at trapping heat over a 100-year period and 86 times stronger over 20 years. While natural gas when burned emits less CO2 than coal, that doesn’t mean it’s clean. Whereas global warming triggered by massive release of CO2 is catastrophic, the release of CH4 from methane hydrates is potentially apocalyptic. According to Brand (2016) the leaking of methane from permafrost and shelf sediment constituted the factor underlying the mass extinction at the end of the Permian 251 million years ago, when 96% of species were lost, a critical observation for humanity regarding greenhouse gas emissions, global warming, and the life support system of the planet. According to Kevin Trenberth, chief scientist of the National Center for Atmospheric Research in Boulder, Colorado: “Some of the human-induced changes are occurring 100-times faster than they occur in nature … And this is one of the things that worries me more than climate change itself. It’s actually the rate of change that’s

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(a)

(b)

(c)

Fig. 9.6 a Coal seam gas extraction: Fracking sites in Wicket, Texas. Photo: Dennis Derick, creative commons; b global gas fields; c model coal seam gas field

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most worrying … Ecosystems are not prepared for this jolt … And neither are many human endeavors”. As governments continued to subsidize (Glenday, 2021) mining and export of hydrocarbons to the astronomical level of 5.9 trillion dollars in 2020, the current pledges in COP26 for zero-emissions by 2050 remain questionable (McLaren, 2019). Examples for major on-shore and off-shore hydrocarbon exploitation include Saudi-Arabia, the Gulf States, Russia, Norway and Australia. A mostly compliant media highlights a zero-emission pledge but is reluctant to report the scale of exported emissions as well as the ultimate consequences of the open-ended rise of global temperatures (Morgan, 2021). For example Norway, a country committed to domestic clean energy, is conducting large scale drilling for Atlantic and Arctic oil. Australia, the fourth-largest producer of coal, with 6.9% of global production, is the biggest net exporter, with 32% of global exports in 2016. 23 new coal projects are proposed n the Hunter Valley, NSW, with a production capacity equivalent to 15 Adani-sized mines (Denniss et al., 2021). As indicated by the International Monetary fund toxic greenhouse gas pollution is funded by tax payers world-wide through government subsidies (Parry et al., 2021) or about 6.8% of GDP, and are expected to rise to 7.4% of GDP in 2025. Australian electricity generation is dominated by fossil fuel and about 17% renewable energy. Fossil fuel subsidies hit about twice the investment in solar energy in 2019–2020 $10.3 billion in 2020–21 (Atholia et al., 2020). State Governments spent $1.2 billion subsidizing exploration, refurbishing coal ports, railways and power stations and funding “clean coal” research, ignoring the pledge for “zero emissions by 2050”. At the current rate of emissions, atmospheric CO2 levels would be near 500 ppm CO2 by 2050, generating warming of the oceans, decreasing albedo due to melting of ice, enhancing release of methane, desiccation of vegetation and extensive fires. Claims of “clean coal”, “clean gas” and “clean hydrogen” ignore the contribution of these methods to the rise in greenhouse gases (Long, 2017). Coal seam gas has become an additional source of methane, with a ~80 times more powerful greenhouse effect than CO2 . This adds to the methane leaked from Arctic permafrost. Since 1880, Earth surface temperatures have risen by an average of 0.08 °C per decade. The rate of warming over the past 40 years was 0.18 °C per decade since 1981. Averaged across land and ocean, the 2020 surface temperature was 0.98 °C warmer than the twentieth-century average of 13.9 °C) and 1.19 °C warmer than the pre-industrial period (1880–1900) (Lindsay & Dahlman, 2022). Since the 1980s, the wildfire season has lengthened across a quarter of the world’s vegetated surface. It is not clear how tracking toward + 4 °C (Vince, 2019) by the end of the century can be arrested. A level of + 4 °C above preindustrial temperature reached at the rate of 2–3 pm O2 and higher endangers the very life support systems of the planet (Glikson, 2013a, b). The geological record indicates past global heating events on a scale and rate analogous to the present have led to mass extinction of species. According to Will Steffen, Australia’s top climate scientist “we are already deep into the trajectory towards collapse”. While many scientists are discouraged by the extreme rate of global heating, it is left to

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a heroic young girl, Greta Thunberg (Watts, 2019) (Fig. 9.7) to warn the world of the greatest calamity since a large asteroid impacted Earth some 66 million years ago. The COP26 and subsequent COP27 meetings have been disasters. Climate scientists have practically been excluded from the meetings, including authorities such as James Hansen, Michael Mann, Joachim Schellnhuber, Will Steffen and other. With the remarkable exception of David Attenborough and few others, including references by the Bulletin of Atomic Scientists to “100 seconds to midnight” (Mecklin, 2022), science-based projections of global heating have received faint echoes among the assembly of warring tribes at conferences dominated by national and corporate vested interests. Mean global temperatures hardly represent an accurate picture of the effects of global warming, it is the rate of change which primarily affects the ability of the biosphere to adapt. According to NOAA “the impacts of climate change have not been spread evenly around our planet … the strongest warming happening in the Arctic during its cool seasons and in Earth’s mid-latitude regions during the warm season”. The atmospheric concentration of greenhouse gases, which rose by near-50% since pre-industrial time, is only rarely mentioned in the popular media Fig. 9.7 Greta Thunberg, Wikipedia commons

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and by politicians, nor are levels of methane, which have risen about 3-fold, and of nitrous oxide, being highlighted in the media. While opinions by journalists, politicians, economists and social scientists are widely promulgated, less attention is given to what is indicated by climate science. According to Hans Joachim Schellnhuber, Germany’s former chief climate scientist: “The Earth system’s responses to climate change appear to be non-linear … If we venture far beyond the 2 degrees guardrail, towards the 4 degrees line, the risk of crossing tipping points rises sharply”. According to James Hansen, NASA’s former chief climate scientist: “Burning all fossil fuels would create a different planet than the one humanity knows. The palaeoclimate record and ongoing climate change make it clear that the climate system would be pushed beyond tipping points, setting in motion irreversible changes, including ice sheet disintegration with a continually adjusting shoreline, extermination of a substantial fraction of species on the planet, and increasingly devastating regional climate extremes” (Hansen et al., 2012).

References Atholia, T. D. (2020). Australian Economy, Renewable Energy Investment in Australia Bulletin— March 19, 2020. Brand, U. (2016). Methane hydrate: Killer cause of Earth’s greatest mass extinction. Palaeoworld, 25(4), 496–507. Bronselaer, B., et al. (2018). Change in future climate due to Antarctic meltwater. Nature, 564(8), 53–58. Burke, K. D., et al. (2019). Pliocene and Eocene provide best analogs for near-future climates. Proceedings of National Association of Sciences, 115(52), 13288–13293. Chi, X., et al. (2020). Future of the human climate niche. Proceedings of National Academy Sciences, 117(21), 11350–11355. Coady, D. et al. (2019). Global fossil fuel subsidies remain large: An update based on country-level estimates. International Monetary Fund Working Paper, 2019/089. Collins, L., et al. (2021). The 2019/2020 mega-fires exposed Australian ecosystems to an unprecedented extent of high-severity fire. Environmental Research Letters, 16, 4. Denniss, R. (2021). One step forward, two steps back: New coal mines in the Hunter valley. The Australia Institute, March, 2021. Glenday, G. (2021). Calls to phase out fossil fuel subsidies after speculation about net-zero emissions target. BABC News, 26 April, 2021. Glikson, A. Y. (2013a). IPCC climate trends: Blueprints for tipping points in Earth’s climate. The Conversation, September 29, 2013a. Glikson, A. Y. (2013b). Existential risks to our planetary life-support systems Published: September 5, 2013b. Glikson, A. Y. (2019). From stars to brains: Milestones in the planetary evolution of life and intelligence (159 pp). Springer. Glikson, A. Y. (2021). The climate change runaway chain reaction-like process: Amplifying feedbacks leading to accelerated planetary temperatures. Arctic News, June 20, 2021. Hansen, J., et al. (2012). Perception of climate change. Proceedings of the National Academy of Sciences, 109, 14726–14727. Hansen, J., & Makiko, S. (2021). The world has cooled off—What’s the significance? Columbia.edu. 13/5/2021. Hansen, J., et al. (2013). Climate forcing growth rates: Doubling down on our Faustian bargain. Environmental Research Letters, 8/011.

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Hansen, J., et al. (2022, January). Temperature update: The New Horse Race, 14/2/2022. Hansen, J. M., et al. (2016). Ice melt, sea level rise and superstorms: Evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous. Atmospheric Chemistry and Physics, 16, 3761–3812. Heilig, G. K. (1994). The greenhouse gas methane (CH4 ): Sources and sinks, the impact of population growth, possible interventions. Population and Environment, 16, 109–137. Knutti, R., & Sedlacek, J. (2012). Robustness and uncertainties in the new CMIP5 climate model projections. Nature Climate Change, 3(4). Kraemer, D. (2021). Greta Thunberg: Who is the climate campaigner and what are her aims? BBC News, 5 November, 2021. Krajick, K. (2019). Wallace Broecker, prophet of climate change. A world explorer of oceans and atmosphere, 1931–2019. Columbia Climate School, 19 February, 2019. Kump, L. R. (2011). Ocean anoxia: The end-permian mass extinction. Eos, 19, 46. Lashof, D. (2020). Why positive climate feedbacks are so bad. World Resources Institute. https:// www.wri.org/insights/why-positive-climate-feedbacks-are-so-bad Lindsay, R., & Dahlman, L. (2022). Climate change global temperatures. NASA Climate.gov. June 28, 2022. Long, S. (2017). Methane emissions from coal seam gas development raise climate change concerns. ABC News, 28 February, 2017. McLaren, D. (2019). Guest post: The problem with net-zero emissions targets. Carbon Brief , 30 September, 2019. Mecklin, J. (2022). At doom’s doorstep: It is 100 seconds to midnight. Science and Security Board, Bulletin of the Atomic Scientists Morgan, J. (2021). Stop exporting the climate crisis. Al Jazeera. Morton, A. (2020). Scott Morrison’s ‘gas-led recovery’: What is it and will it really make energy cheaper? The Guardian, September, 2020. Murphy, K., & Karp, P. (2021). Australian energy board chair says gas-fired power plant in Hunter Valley ‘doesn’t stack up’. The Guardian. Parry, W. H. et al. (2021). Still not getting energy prices right: A global and country update of fossil fuel subsidies. 24 September, 2021. Ritchie, H., & Roser, M. (2016). CO2 emissions: Our world in data. https://ourworldindata.org/ co2-emissions#citation Rowlatt, J. (2021). COP26: World at one minute to midnight over climate change, November 1, 2021. Schuur, T. (2019). Permafrost and the global carbon cycle. Center for Ecosystem Science and Society. Staten, P. W., et al. (2018). Re-examining tropical expansion. Nature Climate Change, 8, 768–775. Struzik, E. (2020). How thawing permafrost is beginning to transform the Arctic. Yale Environment 360. Turrentine, J. (2019). The natural gas industry has a methane problem, June 7, 2019. https://www. nrdc.org/onearth/natural-gas-industry-has-methane-problem Vince, G. (2019). The heat is on over the climate crisis. Only radical measures will work. The Guardian. Sun 19 May, 2019. Wallace-Wells, D. (2017). The uninhabitable earth. Intelligencer, New York Magazine. Ward, P. D. (2006). Impact from the deep. Scientific American, 295(4), 64–71. Watts, J. (2019). Greta Thunberg, schoolgirl climate change warrior: ‘Some people can let things go. I can’t’. The Guardian, 11 March, 2019.

A Burning Planet

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Average global land-ocean temperatures (Fig. 10.1) do not tell the whole climate story where the increasingly frequent weather anomalies take over extensive regions (Fig. 10.2), including rapid Arctic melt, heatwaves, fires, storms and cyclones, underpinning a fundamental shift in the state of the terrestrial climate. It has been stated “What happens in the Arctic doesn’t stay in the Arctic”. Temperatures in the Arctic reached 34 °C in July 2019, the hottest month on the planet, affecting melting over 700,000 km2 in Greenland in late May 2019. The weakening of the circum-Arctic jet stream ensues in its undulation and intersection by warm air masses moving north and cold air masses moving south, along with ice melt from the Greenland ice sheet forming cold regions in the North Atlantic Ocean (Rahmstorf, 2015) “Scientists agree that climate change is happening faster than predicted” (Fritz & Ramirez, 2021). More than one-third of the world’s soil, producing 95% of the world’s food supply, is currently degraded. By 2035 air pollution is projected to be a top cause of environmentally-related deaths worldwide, whereas half the world’s population will face water shortages. Comprehensive reports and analyses by the International Panel for Climate Change (IPCC), intended to estimate temperature projections, raise numerous problems. The IPCC has underestimated (Scherer, 2012) the scale and rate of global warming and its consequences, including the rates of Arctic and Greenland ice melt and sea level rise. In the background is a reluctance by many scientists to warn the public about the cataclysmic consequences of accelerating global heating. As stated by Joachim Schellnhuber, Germany’s chief climate scientist, we are looking at an “existential risk to the life support systems of the planet”. From 1751 the pH value of the ocean surface waters is estimated to have decreased from approximately 8.25 to 8.07 (Fig. 10.3). During this time, the pH of surface ocean waters has fallen by 0.1 pH units, i.e. on a logarithmic representing approximately 30 percent increase in acidity. Many are reluctant to warn the public of the full implications of global heating for the habitability of Earth. Issuing public warnings Cassandra-like may incur a

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Fig. 10.1 a Fires around the world. Moderate spectral resolution. NASA. b Fires burning throughout Australia as seen in this January 22 NASA satellite fire maps over seven days. c Fires are burning through southeast Australia, as seen in this January 22 NASA satellite map of fires over the seven previous days. NASA

heavy price, including social and professional isolation, psychological effects and loss of professional positions. Many self-censor, are suppressed or dismissed from institutions, including a common reluctance by self-censored scientists and the media to publish climate change reports. Powerful psychological factors prevent many scientists from expressing their worst fears, where at times personal optimism may overcome realism. As cited in the article titled When the End of Human Civilization Is Your Day Job (Richardson, 2015): “Among many climate scientists, gloom has set in. Things are worse than we think, but they can’t really talk about it” and “in private conversations, many climate scientists express far greater concern at the progression of global warming and its consequences than they do in public”. It

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Fig. 10.2 How climate change is affecting world regions. By Katherina Buchholz

is not uncommon to hear people criticizing climate scientists for not telling them more about the future climate, but when people are told, many recoil. Too many are soothed by the plethora of false promises by politicians broadcast by the corporate media, notwithstanding hollow pledges made at climate conferences such as at COP26, a meeting noted for the near-absence of contributions by climate scientists (Fig. 10.4).

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Fig. 10.3 a Graph showing rising levels of carbon dioxide (CO2 ) in the atmosphere, rising CO2 levels in the ocean and decreasing pH in the water off the coast of Hawaii. As carbon dioxide rises in the atmosphere, some of it dissolves into seawater, increasing the CO2 concentration and reacting with water to form hydrogen ions which drive the pH down, leading to ocean acidification. b Vertical section of pCO2 in a transect line 5 off Pt. St. George, California. NOAA. Wikipedia commons

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Fig. 10.4 On icebergs and climate conferences. Captions by Andrew Glikson

References Fritz, A., & Ramirez, R. (2021). Earth is warming faster than previously thought, scientists say, and the window is closing to avoid catastrophic outcomes. CNN. https://edition.cnn.com/2021/ 08/09/world/global-climate-change-report-un-ipcc/index.html Rahmstorf, S. (2015). Exceptional twentieth-century slowdown in Atlantic ocean overturning circulation. Nature Climate Change, 5, 475–480. Richardson, J. H. (2015). When the end of human civilization is your day job. August 2015 issue of Esquire. Scherer, G. (2012). How the IPCC Underestimated Climate Change: Here are just eight examples of where the IPCC missed predictions. DailyClimate.org. December 6, 2012.

Paleoclimate Implications

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Since the onset of the industrial age about 1750, through the nineteenth and the twentieth centuries, and in particular post World War II, early global greenhouse gas levels and warming rates (~0.82 °C during 1950–1980) (Table 11.1; Fig. 11.1) have risen by high factors to an order of magnitude higher than in the pre-industrial age, rising at rates faster than during some of the past geological mass extinction events, with major implications for nature and for human civilization: A. The rise in the Anthropocene CO2 and warming rates exceeded those of the Last Glacial Termination (LGT) (21–8kyr), the Paleocene-Eocene hyperthermal event (PETM) (55.9 Ma) and the aftermath of the Cretaceous-Tertiary boundary (K-T) (64.98 Ma). B. Further to NASA’s reported mean land–ocean temperature rise of + 0.82 °C in May 2022, relative to the 1951–1980 baseline, large parts of the continents such as central Asia, west Africa eastern South America and Australia are warming toward mean temperatures of + 2 °C and higher. C. Major consequences of the current shift in state of the climate system pertain to the weakening of the polar jet stream boundaries and the migration of climate zones toward the poles. Transient stadial cooling pauses ensue from the flow of cold ice melt water into the oceans from Greenland and Antarctica, leading to future stadial cooling intervals and polar-ward shift in the position of climate zones. D. Given the abrupt shift in state of the atmosphere–ocean-cryosphere-landsystem, the current trend signifies an abrupt dislocation of climate zones toward the poles, accelerating since the mid-twentieth century. For this reason terms such as “climate change” and “global warming” no longer reflect the nature of the climate shift, which amounts to a climate catastrophe on a geological scale.

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+ 5 to 9 °C

~6000 to 7000 years

PETM 55.9 Ma

CO2ANTH/PETM = x3.9 − 6.9 T°CANTH/PETM = x4.9 − 9.25

CO2ANTH/LGT = x41

T°CANTH/LGT = x16

CO2

TEMP

T°CANTH/KT = x9.9

CO2ANTH/KT = x2.3

Anthropocene/KT

− 0.44 ppm/year

0.010 ppm/year

0.06 to 0.075 ppm/yr

− 0.1 to 0.11 ppm/yr

0.18 ppm/yr

CO2 change rate (ppm/year)

11

Created by Andrew Glikson

Anthropocene/PETM

Anthropocene/LGT

300 to 420 ppm

− 0.0074

~2 °C Without aerosol albedo effects

270 years

1750–2020

Added 1200 ppm 186 to 265 ppm

0.00025–0.0004 0.00046

5 to 9 °C − 3.5 °C

20,000 years

− 1000 to 1700 ppm; Added 700 ppm

− 0.0008–0.0015

7500 years

− 500 to 2300 ppm

− 0.00075

PETM

CO2 change (ppm)

Warming rate (°C/yr)

The Last Glacial Termination; 17.5–10 kyr

Short freeze followed by ~ + 7.5 °C

10,000 years from the impact

K-T impact 64.98 Ma

Mean land and sea temp change °C

Interval (warming period)

Age

Table. 11.1 Paleoclimate estimates of mean land and sea temperatures, mean CO2 concentrations (ppm) and mean T°C rise rates per year

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Fig. 11.1 Cenozoic and Anthropocene CO2 and temperature rise rates. By Andrew Glikson

The rates at which atmospheric composition and climate changes take place exert a major control over the survival versus extinction of species. Based on paleoproxy estimates of greenhouse gas levels and mean palaeo-temperatures, using oxygen and carbon isotopes, fossil plants, fossil organic matter, and trace elements, the rate of CO2 rise since ~1750 (CO2 ANTH ) exceeds that of the last glacial termination (CO2 LGT ) by an order of magnitude (rates CO2 ANTH /CO2 LGT = 41) and that of the Paleocene-Eocene Thermal Maximum (rate CO2 PETM ) by a high factor (rates CO2 ANTH /CO2 PETM ~ 3.8–6.9). Thus the current rise rate of mean global temperature exceeds that of the LGT and the PETM by a large factor to an order of magnitude. Major advances of science and engineering since the seventeenth century, when the coal-powered steam engine was invented, magnified human power by orders of magnitudes, allowing it to affect the terrestrial atmosphere, the oceans and biodiversity and act as a geological agent. By the mid-twentieth century Global CO2 rise and warming rates have accelerated relative to past geological warming and mass extinction events, leading to rapid shifts of climate zones, extreme weather events and biological diversity. IPCC climate projections for 2100–2300 delineate linear trends (Fig. 11.1). However climate modelling by Hansen et al. (2016) suggests significant effects of ice melt flow into the oceans from Greenland and Antarctica, leading to stadial cooling, affecting the global temperature pattern (Hansen et al., 2012, 2016). Comparisons between the current rise rate of greenhouse gases and of temperatures and major warming events in the geological past are alarming. Estimates of

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Fig. 11.2 A comparison between rates of mean global temperature rise during: (1) The last glacial termination, after Shakun et al. (2012); (2) the PETM (Paleocene-Eocene Thermal Maximum, after Kump, 2011); (3) the late Anthropocene (1750–2019), and (4) an asteroid impact. In the latter instance, temperature associated with CO2 rise would lag by some weeks or months behind aerosol-induced cooling. By Andrew Glikson

the magnitude and rates of change of greenhouse gases and of temperature based on the literature are given in Table 11.1 (Fig. 11.2). The CO2 and temperature rise rates induced by the K-T at 65.9 million years ago must have been near-instantaneous at first, followed by gradual warming effects. The K-T impact and subsequent warming involved a rise from about 400– 500 ppm to 2300 ppm CO2 over 10.000 years since the impact (Fig. 11.3) at a rate of 0.18 ppm/year. This is less than the mean Anthropocene CO2 rise rate of 0.44 ppm/year and an order of magnitude less than the 2 to 3 ppm/year rise rate in the twenty-first century. Likewise the Anthropocene temperature rise rate of ~0.0074 °C/year is high by an order of magnitude as compared to the K-T impact event rate of ~0.00075 °C/year (Table 11.1). Estimates based on fossil fern proxies, an initial injection of at least 6400 GtCO2 and possibly as high as 13,000 GtCO2 into the atmosphere, whereas significantly higher than values are derived by Pope et al. (1997). This would increase climate forcing by + 12 Watt/m−2 and mean warming by ~7.5 °C, which strongly stressing ecosystems already affected by cold temperatures and the blockage of sunlight during the impact winter and associated mass extinction at the K-T boundary (O’Keefe & Ahrens, 1989). A runaway climate chain reaction-like process triggered by release of methane is believed to have occurred during the Paleocene-Eocene thermal maximum (PETM), about 55.9 million years ago (Table 11.1; Fig. 11.4). The event triggered the release of a large mass of light 13 C-depleted carbon suggestive of an organic source, likely methane, leading to a global surface temperature rise. According

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Fig. 11.3 Reconstructed atmospheric CO2 variations during the Late Cretaceous–Early Tertiary, derived from the SI of fossil leaf cuticles calibrated by using regression and stomatal ratios

to McInerney and Wing (2011) during the PETM thousands of Gigagram (billion grams) of carbon were released into the ocean–atmosphere system triggering changes to the carbon cycle, climate, ocean chemistry, and marine and continental ecosystems over a period ranging from < 20 kyr to ∼200 kyr, with a consequent rise of global temperature by 5–8 °C. Terrestrial and marine organisms experienced large shifts in geographic ranges and few groups suffered major extinctions, with the exception of benthic foraminifera. Meissner (2014) outlines three models of the PETM, including: (1) a low-carbon scenario: late Paleocene atmospheric CO2 concentration of 840 ppm and a PETM carbon pulse of 7000 GtC (GtC = one billion tons of carbon); (2) a medium-carbon scenario of 1680 ppm and 7000– 10,000 GtC, and (3) a high-carbon scenario (2520 ppm and > 10,000 GtC). The low- and medium-carbon scenarios fit best with pre-PETM absolute temperature reconstructions. According to Gingerich (2019) modern carbon emission rates are some 9–10 times higher than those during onset of the PETM. If the present trend of anthropogenic emissions continues, we can expect to reach a PETM-scale accumulation of atmospheric carbon in as few as 140 to 260 years, i.e. in about 5 to 10 human generations. The magnitude and the rise rates of greenhouse gases and temperature (Table 11.1) had major effects on global temperature and on climate. Paleoclimate indices based on ice cores and isotopic evidence suggest that during the Last Glacial Termination (LGT) (17.5–10 kyr ago) temperature rise was near-parallel to the rise in CO2 (Fig. 11.5). A rise rate of ~0.010 ppm CO2 /year and of temperature ~0.00046 °C/year are indicated by Shakun et al. (2012). A data compilation by Sam Carana indicates the current warming rate may reach orders of magnitude higher than previous geological rates (Fig. 11.6).

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Fig. 11.4 a The Paleocene-Eocene thermal maximum; b The Palaeocene–Eocene thermal maximum recorded by isotopic data of benthic plankton from sites in the Antarctic, south Atlantic and Pacific (Zachos et al., 2003). The rapid decrease in oxygen isotope ratios is indicative of a large increase in atmospheric temperatures associated with a rise in greenhouse gases CO2 and CH4 signifies approximately + 5 °C warming

Fig. 11.5 Global CO2 and temperature during the last glacial termination (modified after Shakun et al. 2012) (LGM—Last glacial maximum; OD—Older dryas; B-A—Bølling–Allerød; YD— Younger dryas)

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Fig. 11.6 Geological and modern rates of temperature rise. Created by Sam Carana (Arctic News Blogspot.com.) Warming rates may be transiently retarded by the flow of cold ice melt water into the oceans from the Greenland and Antarctic ice sheets

References Gingerich, P. G. (2019). Temporal scaling of carbon emission and accumulation rates: Modern anthropogenic emissions compared to estimates of PETM onset accumulation. AGU Paleoceanography and Paleoclimatology, 34(3), 329–335. Hansen, J., et al. (2012). Perception of climate change. Proceedings of the National Academy of Sciences, 109, 14726–14727. Hansen, J. M., et al. (2016). Ice melt, sea level rise and superstorms: Evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous. Atmospheric Chemistry and Physics, 16, 3761–3812. Kump, L. R. (2011). Ocean anoxia: The end-Permian mass extinction. EOS, 19, 46. McInerney, F. A., & Wing, S. L. (2011). The Paleocene-Eocene thermal maximum: a perturbation of carbon cycle, climate, and biosphere with implications for the future. Annual Review of Earth and Planetary Sciences, 39. Meissner, K. J. (2014). The Paleocene-Eocene thermal maximum: How much carbon is enough? Paleoceanography and Paleoceanography, 29(10), 946–963. O’Keefe, J. D., & Ahrens, T. (1989). Impact production of CO2 by the cretaceous/tertiary extinction bolide and the resultant heating of the earth. Nature, 338, 247–249. Pope, K. O., et al. (1997). Energy volatile production and climatic effects of the Chicxulub cretaceous/tertiary impact. Journal of Geophysical Research, 102, 21645–21664. Shakun, J. D., et al. (2012). Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation. Nature, 484, 49–55. Zachos, J., et al. (2003). Climate change 2007: Working group I: The physical science basis. https:// archive.ipcc.ch/publications_and_data/ar4/wg1/en/figure-6-2.html

Climate Zones Shifts, Ice Melt and Stadial Cooling

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The shift in state of the climate system includes weakening of the polar jet stream boundaries, with consequent intrusion of cold fronts and warm fronts through the boundary, expansion of tropical and subtropical climate zones and migration of climate zones toward the poles (Fig. 12.1). Transient cooling pauses are projected as a result of the flow of cold ice melt water from Greenland and Antarctica into the oceans, leading to stadial cooling intervals. The shift in climate zones constitutes a consequence of: • Expansion of tropical and subtropical climate zones from the tropics toward moderate and northern climate zones (Figs. 12.1a–c, 12.2 and 12.3). • Flow of ice melt water from Greenland and Antarctic cold ice melt water into the North Atlantic and circum-Antarctica oceans (Figs. 12.4 and 12.5). • Reduced temperature differences between the polar zones and mid-latitudes and thereby weakening of the polar boundaries and the polar jet stream boundary, allowing penetration of cold and warm air masses across the boundary. • Weakening of the North Atlantic Thermal Circulation and changes in the southern ocean Antarctic oscillation and the Antarctic vortex (Figs. 12.5, 12.6 and 12.7). • The rapid increase in extreme weather events, including droughts, heat waves, fires, cyclones and storms.

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Fig. 12.1 a Southward encroachment of Kalahari Desert conditions (vertical lines and red spots) leading to warming and drying of parts of southern Africa. With permission of the IOM UN Migration. b Migration of the subtropical Sahara climate zone (red spots) northward into the Mediterranean climate zone leads to warming, drying and fires over extensive parts of Spain, Portugal, southern France, Italy, Greece and Turkey, and to melting of glaciers in the Alps. c Drying parts of southern Australia, including Western Australia, South Australia and parts of the eastern States, accompanied by increasing bushfires. With permission of the IOM UN Migration (International Organization for Migration [IOM])

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Fig. 12.1 (continued)

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Fig. 12.1 (continued)

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Fig. 12.2 The global consequence of the shift in climate zones. Global climate changes to 1.5 and 2.0 °C. Temperature change is not uniform across the globe. Projected changes are shown for the average temperature of the annual hottest day (top) and the annual coldest night (bottom) with 1.5 °C of global warming (left) and 2 degrees Celsius of global warming (right) compared to pre-industrial levels. Image credit: NASA

Fig. 12.3 a Migration of climate sones in Erope during 1981–2010 and under + 2 °C. Faint pink reas represent advanced warming according to model RCP8.5. b Ensemble median spatial patterns of agro-climate zones migration under 2 °C global surface warming according to model RCP8.5. IPCC

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Fig. 12.4 Global warming map (NASA, Creative Commons Non-commercial Attribution (CC BY-NC-SA 3.0 AU)). Note the cold regions south of Greenland (Goddard Space Flight Center) and the circum-Antarctic ocean. Scientific visualization Studio, NASA

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Fig. 12.5 a, b Expansion of Arctic –sourced cold fronts across the jet stream into northern and mid-latitudes. The polar jet stream (Berwyn, 2018) can be several miles deep and more than 100 miles wide, allowing penetration of cold and warm air masses, with the strongest winds typically 5 to 10 miles above the ground. In this NASA visualization the fastest winds are in red; slower winds are in blue. Credit: NASA; c Portrayal of the jet stream over North America; d clouds along a jet stream over Canada. Wikipedia

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Fig. 12.6 Circum-Antarctic vortices driven by extending strong westerly wind swirls of the Antarctic polar system curl over the southern continents (NASA, Galileo)

With climate zones shifting, at an estimated rate of 56–111 km per decade (Turton, 2017) ecosystems have only a short time to adapt, arid zones expand and droughts and fires consume moderate-climate forests and formerly fertile habitats. As the tropical climate zones expand toward the poles, intermediate (Mediterranean) climate zones shift and contract polar-ward, clashing with polar-derived cold air and ice melt water flowing through weakened jet stream boundaries. Allen et al. (2012) suggest the increase in black carbon aerosols and tropospheric ozone constitute significant factors generating a polar-ward shift of moderate climate zones. The effects of encroaching deserts and of fire storms on terrestrial forests, which developed originally under moderate conditions distinct from those during accelerating global warming and extreme weather events, may have been underestimated. Mean global temperatures do not tell the whole story—it is the increasingly frequent extreme weather anomalies which do.

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Fig. 12.7 Development of a major younger dryas-like stadial. a An A1B model of surface-air temperature change for 2055–2060 relative to 1880–1920 (+1 m sea level rise) for modified forcing (Hansen et al., 2016); b A1B model surface-air temperatures in 2096 relative to 1880–1920 (+5 m sea level rise) for 10 years ice melt doubling time in the southern hemisphere and partial global cooling of − 0.33 °C (Hansen et al., 2016). CC Attribution 3.0 License. c Model 2080–2100 meltwater-induced sea-air temperature anomalies relative to the standard model RCP8.5 ensemble (Bronselaer et al., 2018), indicating marked cooling of parts of the southern oceans. Hatching indicates where the anomalies are not significant at the 95% level

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References Allen, R. J., et al. (2012). Recent Northern Hemisphere tropical expansion primarily driven by black carbon and tropospheric ozone. Nature, 485, 350–354. Berwyn, B. (2018). Polar vortex: How the jet stream and climate change bring on cold snaps. Inside Climate News. Bronselaer, B., et al. (2018). Change in future climate due to Antarctic meltwater. Nature, 564(8), 53–58. Hansen, J. M., et al. (2016). Ice melt, sea level rise and superstorms: Evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous. Atmospheric Chemistry and Physics, 16, 3761–3812. Turton, S. M. (2017). Expansion of the tropics: Revisiting frontiers of geographical knowledge. Geographical Research, 55(122), 3–12.

Future Climate Projections

13

The extremely short time scale of the Anthropocene global warming as compared to the Paleocene-Eocene Thermal Maximum (PETM) (at ~56 Ma) and to the Last Glacial Termination (LGT), suggests the Anthropocene event is quantitatively and qualitatively a unique period different from previous global warming events. The paleoclimate evidence allows projections of future composition of the atmosphere and oceans and thereby the habitability of land and ocean (Berger & Loutre, 2002; Zeebe & Zachos, 2013). Assuming unabated anthropogenic emissions of carbon dioxide (CO2 ) with the emission of 5000 billion tons carbon (PgC), driving atmospheric CO2 to approximately 2000 ppm, global temperature would rise by over 8 °C and ocean pH decline by approximately 0.7 units. A carbon release of this magnitude has no parallel since 56 million years ago, the Palaeocene–Eocene Thermal Maximum (PETM). A comparison between the duration of carbon release during the Anthropocene vs the PETM, including the effects on ocean acidification and marine calcifying organisms, bears worrying implications for a potential future mass extinction event (Figs. 13.1, 13.2, 13.3 and 13.4). Palaeoclimate-based projections in 1972 raised the possibility of an exceptionally long interglacial, lasting another 50,000 years, longer than the 10,000 yearslong Eemian (~125,000 years ago; Berger & Loutre, 2002). The gradual cooling which commenced at the peak Holocene 6000 years ago was projected to lead to a cold interval from about 25,000 years in the future and to glaciation in about 55,000 years in the future. The current anthropogenic greenhouse effect introduces an entirely new scenario, extending the Holocene interglacial to perhaps the length of MIS-11 (Marine Isotope Stage-11) of ~50,000 years (424,000 to 374,000 BP). As a corollary future low eccentricity periods ensue in long interglacial periods, reducing the variations of precession. The stabilization of insolation would be negated by greenhouse gas-induced variations. Future climate simulations for the next 100,000 years, as a function of insolation and CO2 variations, outline possible consequences of the current greenhouse gas rise, leading to an exceptionally long interglacial (Fig. 13.4).

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Fig. 13.1 Tertiary to glacial-interglacial and Holocene temperature profile

Increased eccentricity results in rising insolation and marked seasonal climate contrasts. Marked fluctuations in temperatures occurred to during the Last Glacial Termination, including the Younger dryas, followed by gradual cooling during the Holocene. The levels of greenhouse gases rose slightly during the Medieval Warm Period, rising abruptly at the outset of the Anthropocene about ~1750 AD (Fig. 10.1). The current level of atmospheric CO2 concentration of ~420 ppm and rising is already well above typical interglacial values of ∼280–300 ppm. In their model Berger and Loutre (2002), consistent with Kukla et al. (1997), assume a CO2 rise to 750 ppm over the next 200 years, a level at which the Greenland and west Antarctic ice sheets would totally melt and the climate may take another 50,000 years to recover from anthropogenic warming. This agrees with the suggestion that under the present-day insolation regime and preindustrial CO2 concentrations, no glacial inception is possible and the range of future climate conditions is likely to be similar to the warmest phases of the last few tens of millions of years. In trying to avoid an exponential rise in greenhouse gases toward catastrophic levels, urgent attempts are needed at drawing down at least part of the CO2 from the atmosphere. The $trillions of dollars required, constituting the “Price of the Earth”, need to replace the $trillion dollars military expenses spent by the world over the last 70 years, including nuclear missile fleets that constitute a distinct threat for life on Earth. As warned by Albert Einstein: “The unleashed power

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Fig. 13.2 The late glacial termination (LGT) and the Holocene. Licensing: https://earthwise.bgs. ac.uk/index.php/File:P916095.jpg

of the atom has changed everything save our modes of thinking and we thus drift toward unparalleled catastrophe”.

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Fig. 13.3 Hansen et al.’s (2016) climate projection to the end of the twenty-first century

Fig. 13.4 Simulated Northern Hemisphere ice volume for 200,000 years before the present to 130,000 from the present. For the future, three CO2 scenarios were used: solid line -- last glacialinterglacial values; dashed line -- human-induced concentration of 750 ppmv; dotted line ….. cooling for CO2 concentration of 210 ppm (Berger & Loutre, 2002)

References

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References Berger, A., & Loutre, M. F. (2002). An exceptionally long interglacial ahead? Science, 297(5585), 1287–1288. Hansen, J. M., et al. (2016). Ice melt, sea level rise and superstorms: Evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous. Atmospheric Chemistry and Physics, 16, 3761–3812. Kukla, G., et al. (1997). How long and how stable was the last interglacial? Quaternary Science Reviews, 16(6), 605–612. Zeebe, R. E., & Zachos, J. C. (2013). Long term legacy of massive carbon input to the Earth system: Anthropocene vs Eocene. Philosophical Transactions of the Royal Society, 3.

The Nuclear Nightmare

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Living on borrowed time on a rapidly warming planet engulfed by bush fires, collapsing glaciers, floods and rising oceans, the last thing needed is the growing threat of a nuclear war between superpowers possessing fatal arsenals capable of poisoning the atmosphere, the water and billions of living creatures (Fig. 14.1). The current impasse between two superpowers, the US versus Russia + China, threatening to grow into a nuclear war, endangering the future of civilization and much of nature, echoes the Peloponnesian wars between Athens and Sparta for control of the Aegean world (Figs. 14.2 and 14.3), as witnessed by Thucydides, the Greek general and historian. Throughout history when a great power was threatened by the rise of another, with few exceptions the stronger adversary would try to arrest the growth of the new one, a strategy labelled “The Thucydides Trap”. As Thucydides, wrote: “It was the rise of Athens and the fear that this instilled in Sparta that made war inevitable.” In the nuclear age such confrontation amounts to a global suicide. An analogous situation has emerged in the wake of World War II during the cold war, where superpowers, the US versus Russia + China are trapped on a collision course on the runaway warming Earth. To date the mutual nuclear threat of the MAD (Mutual Assured Destruction) has prevented war between the superpowers. But memories are short. ”the first casualty of a war is the truth”. A new reality emerges between opponents, where cover ups and double standards prevail. The more aggressive a force the more it asserts it acts “self defence”. A generation has passed since the Hiroshima and Nagasaki atomic bombs and, and as the collective memory of the horrendous consequences is fading a global suicide machine of some 13,000 atomic and hydrogen missiles has emerged. The young and the middle aged may perceive a nuclear holocaust as a surreal nightmare, overlooking the gruesome evidence all around (Fig. 14.4), including on the testing grounds of New Mexico, the Marshall islands, Novaya Zemlya, Kazakhstan, Moruroa atoll, Nevada, Gobi Desert, the Nullarbor and elsewhere.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 A. Y. Glikson, The Trials of Gaia, https://doi.org/10.1007/978-3-031-23709-6_14

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114 Fig. 14.1 “The nuclear winter” by Carl Sagan

Fig. 14.2 Thucydides

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Fig. 14.3 The Peloponnesian war

Fig. 14.4 Yuliy Khariton, the director of the Soviet A-bomb project

Little sympathy can be extended to any superpower that has perpetrated the bloodsheds called “war” through history and more recently. Now that they constructed a 13.000 nuclear missiles-strong global suicide machine, a myriad species, including “Homo sapiens” have been placed on a hair trigger Damocles sword (Fig. 14.5). Media cover-ups prevail blinding many to the hair trigger reality of a nuclear war, superposed on the rapidly accelerating global warming countered by civilization by weasel words. As observed by Noam Chomsky: “The smart way to keep people passive and obedient is to strictly limit the spectrum of acceptable

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Fig. 14.5 The sword of Damocles

opinion, but allow very lively debate within that spectrum.” But while the atmosphere is progressively poisoned by carbon and radioactive isotopes, sport circuses abound, fluorescent screen portray human caricatures oblivious to the reality of life, while few are aware of the ultimate danger to a myriad species, including ours. Orwellian cover-ups, lies and double standards perpetrated by much of the media dominate while planetary consciousness is rare. Where does responsibility lie? It lies with everyone, for losing a sense of reverence toward nature and its multitude of wonderful creatures, for allowing ourselves to join the greedy rat race where “everyone can be a millionaire”, for electing the mouthpieces of criminals, snake oil merchants and turncoats to control our lives. But then responsibility belongs much further. Ultimately it lies with a species which has assumed a god-like omnipotence and a craving for immortality. Whereas the mental capabilities of human ancestors, such as Homo Habilis (2.4–1.4 million years ago), compared with that of advanced primates and other animal species, the harnessing of fire by Homo erectus since about 2.0 million years ago, Neolithic farming, the invention of combustion, electricity and nuclear fission, magnifying human power by orders of magnitude, has allowed the species to disrupt nature through carbon and radioactive poisoning. It is the inability of the human mind to control its own powers which is unleashing what we are witnessing. The Cretaceous-Paleocene boundary (~66 million years-ago) asteroid impact, described in 1980 by Alvarez and colleagues caused enough dust and debris to cloud large parts of planet, leading to the mass extinction of some 80% of all animals species. When prominent scientists warned the world about the climatic effects of a nuclear war, they pointed out that the amount of carbon stored in a large city was sufficient to release enough aerosols (smoke, soot and dust) to

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Fig. 14.6 Global average surface air temperature change from the 5 Tg standard case (red) in the context of climate change over 125 years climate change; NASA data (Robock & Toon, 2012)

block sunlight over large regions, leading to a widespread failure of crops and extensive starvation. Current nuclear arsenals by the United States and Russia could inject 150 Teragram (Tg) (109 kilogram) of soot from fires ignited by nuclear explosions into the upper troposphere and lower stratosphere, lasting for a period of ten years or longer, followed by a period of intense radioactive radiation over large areas. Even a “limited” nuclear war, such as between India and Pakistan, would release enough aerosols to affect large regions, killing millions to billions through starvation. As stated by Robock: “The casualties from the direct effects of blast, radioactivity, and fires resulting from the massive use of nuclear weapons by the superpowers would be so catastrophic … the ensuing nuclear winter would produce famine for billions of people far from the target zones”. By 2021, with a global arsenal of ~13.000 nuclear warheads, 90% of which held by Russia and the US, regional conflicts such as in the Ukraine and Taiwan threaten to spill over world-wide. As the clock of the atomic scientists is set at 100 second to doomsday, the rising probability of an intended or inadvertent nuclear war, in the background of rising global warming, define an hour of truth for the species—a choice between the defence of life and global suicide. While the inhabitants of the planet are preoccupied with the 24 hours news cycle, media hype, superlatives, a deadly Virus, economic issues and sport games, the hair-trigger nuclear gun loaded by the powers east and west are threatening all life on Earth (Fig. 14.1). A release of 5Tg (Tera-gram) (emission of black carbon due to nuclear explosions) is modelled to lower the average global temperature by about 1.5 °C

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Fig. 14.7 Time variation of global average net surface shortwave radiation, surface air temperature, and precipitation changes for the 5 Tg (emission of black carbon due to nuclear explosions). The global average precipitation in the control case is 3.0 mm/day, so the changes in years 2–4 represent a 9% global average reduction in precipitation. The precipitation recovers faster than the temperature, but both lag the forcing. For comparison the global average net surface shortwave forcing from a model simulation of the 1991 Mt. Pinatubo eruption is shown (Robock & Toon, 2012)

(Robock et al. 2007), although over the continents cooling is likely to be more abrupt. Inherent in nuclear war strategy is the “use them or lose them” approach, namely hitting the enemy’s air and missile launch pads before missiles can be launched, which amounts to a virtual guarantee many or most nuclear war heads are potentially used. With the estimated size of the global nuclear warheads many tens of thousands warheads (Fig. 14.8) this guarantees a global catastrophe (Figs. 14.1, 14.8). Such an extreme event would arrest global warming for a period of about 10 years or longer, possibly analogous to the consequences of the cooling effect of major flow of polar ice melt into the oceans, as modelled by Bronselaer et al. (2018). When Sagan and colleagues published their observations of a nuclear winter scenario as a warning to humanity, Sagan was painted as an “alarmist” by many, facing extensive criticism not just from pro-nuclear “conservatives” but also from scientists who resented him for raising his personal fame to advocate what some

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Fig. 14.8 Estimated global nuclear warhead inventories

regarded as political views. A similar situation occurs nowadays with regard to the accelerating global warming and the nuclear threat, confirmed by the warning by the Bulletin of the Atomic Scientists. As stated by the January 20, 2022 Bulletin of the Atomic Scientists news release: “While the past year offered glimmers of hope that humankind might reverse its march toward global catastrophe, the Doomsday Clock was set at just 100 seconds to midnight. The time is based on continuing and dangerous threats posed by nuclear weapons, climate change, disruptive technologies, and COVID-19. All of these factors were exacerbated by “a corrupted information ecosphere that undermines rational decision making.” The Doomsday Clock statement explains that the “decision does not, by any mean, suggest that the international security situation has stabilized. On the contrary, the Clock remains the closest it has ever been to civilization-ending apocalypse because the world remains stuck in an extremely dangerous moment.””

According to the Fermi’s Paradox, the apparent absence of radio-communication between technical civilizations can be attributed to their inevitable short-term selfdestruction as a consequence of uncontrolled invention of lethal methods, including a spread of toxic substances, construction of lethal weapons and contamination of air and water. On Earth this includes saturation of the atmosphere with greenhouse gases and construction of nuclear weapons. The most extensive mass extinction event in the history of Earth is represented by the Permian–Triassic boundary 251 million years-ago when acidification, oxygen depletion of the oceans and related toxic emanations of H2 S and CH4 led to a loss of some 57% of biological families, 83% of genera and 81% of marine

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Fig. 14.9 Battle of Waterloo. Wikimedia

species. If the history of the twenty-first century is ever written it would document that, while large parts of the planet were becoming uninhabitable, the extreme rate and scale of global warming. The migration of climate zones, the extent of polar ice melting, ocean warming, acidification and methane release from permafrost threatened to develop into one of the most extensive mass extinction events in the geological history of planet Earth. As concentrations of atmospheric greenhouse gases exceed 500 ppm CO2 equivalents, consistent with global warming of toward more than 4 °C, climate scientists have been almost banished from much of the media and from conferences and replaced by a plethora of politicians, economists and sociologists mostly ignorant of the physics and chemistry of the atmosphere. Supposed mitigation actions were mostly restricted to reduced emissions, neglecting the amplifying climate feedbacks and tipping points projected by leading climate scientists. Instead an army of pseudoscientists emerged quantifying the cost–benefit economies of mitigation like corner grocers, arguing with the atmosphere and the basic laws of physics. During the twentieth and twenty-first centuries, mostly oblivious to the ultimate consequences of global warming, the rise of Fascism in many parts of the world covered up the ultimate consequences of global warming, keeping humans preoccupied with brutal wars, propagating suicidal weapons, entertained by sport circuses, celebrity cults, gratuitous hubris, frivolous showbiz, canned laughter, and the share market. While Billionaire space cowboys keep throwing fortunes into space small human pockets survive among the wretched of the Earth in remote regions of the planet, strafed by drones sent by the forces of empires. At the root of the MAD (mutual assured destruction) policy, or omnicide, resides deep tribalism and herd mentality of the species, hinging on race, tribalism, territorial claims and the concept of an “enemy”, perpetrated by demagogues and warmongers, leading to an Orwellian 1984 world where “Oceania has always

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Fig. 14.10 “Today, every inhabitant of this planet must contemplate the day when this planet may no longer be habitable. Every man, woman and child lives under a nuclear sword of Damocles…capable of being cut at any moment by accident, or miscalculation, or by madness”. John F. Kennedy

been at war with East-Asia” mimiked in the current “forever wars”. At the core of superpower conflict between the Anglo-Saxon world and the Slavic or Chinese worlds are false claims of moral superiority, in reality naked grabs for power (Fig. 14.9). In the very core of human conscience is its mythological nature, a mindset closely related to the mastery of fire—for longer than one million years, perching at campfire watching the flickering flames, human insights and imagination grew, identifying mortality, developing a fear of death, dreaming of omniscience and omnipotence, aspiring for eternal life. As civilization developed these sentiments were expressed through the constructing pyramids to enshrine immortality, undertake human sacrifice, perpetrating death in order to appease the gods, expressed in modern times through world wars, as conveyed by Albert Einstein: “The splitting of the atom has changed everything bar man’s way of thinking and thus we drift into unparalleled catastrophes” (Figs. 14.10 and 14.11).

14.1

The Fermi Paradox

“I’ve always suspected that the solution to Fermi’s paradox is that if life somewhere is unfortunate enough to develop “higher intelligence”, it’ll find a way to destroy itself through nuclear war, or destruction of the environment.” (Noam Chomsky)

According to the Fermi’s Paradox, the failure to date to achieve radio communication between Earth and extraterrestrial civilizations can be attributed to their inevitable short-term self-destruction, a consequence of uncontrolled dispersion of toxic substances, contamination of air, water and land, or construction of deadly weapons. On Earth this includes mainly saturation of the atmosphere with greenhouse gases and production of nuclear weapons (Fig. 14.13).

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Fig. 14.11 Einstein’s moto and the Redwing hydrogen bomb. We have entered the age of consequences, masked by the 24 hours news cycle which can only portray transient events but rarely exposes the Orwellian lies which underlie the demise in which the powers-that-be are complicit. For just as individuals can be overwhelmed by insanity, so can large groups of people, as in the Jonestown massacre or in Nazi Germany. A nation or a species can slide blindly into mass suicide as in the great World Wars or modern systems that saturate the atmosphere with greenhouse gases and proliferate of nuclear weapons, endangering nature and future generations, constituting a terrestrial confirmation of Fermi’s Paradox (Figs. 14.11, 14.12 and 14.13)

The most extensive mass extinction event in the history of Earth, represented by the Permian–Triassic boundary 251 million years-ago, involved warming, acidification and oxygen depletion of the oceans, with consequent emanations of toxic H2 S and CH4 , leading to a loss of some 57% of biological families, 83% of genera and 81% of marine species. If the history of the twenty-first century is ever written it would report that, while large parts of the planet were becoming uninhabitable, the extreme rate and

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Fig. 14.12 Saturn eating his son: “The first law of humanity is not to kill your children.” Hans Joachim Schellnhuber

Fig. 14.13 Enrico Fermi. Physicist, 1901–1953

scale of global warming and the migration of climate zones, the extent of polar ice melting, ocean warming and acidification, and methane release from permafrost, threatened to develop into one of the most extensive mass extinction events in the geological history of planet Earth. As concentrations of atmospheric greenhouse gases exceed 500 ppm CO2 equivalents, consistent with global warming of more than > 4 °C, driving temperatures to well above 4 °C and threatening to rise at a higher rate than those of the

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Fig. 14.14 Jamesd Edward Hansen climate scientist

great mass extinctions. Climate scientists have been either silenced or replaced by an army of economists and politicians mostly ignorant of the physics and chemistry of the atmosphere, but quantifying the cost–benefit economies of mitigation like corner shop grocers. Proposed mitigation action were mostly focused on reduction of emissions, neglecting the amplifying feedbacks and tipping points projected by leading climate scientists such as James Hansen (Fig. 14.14). But climate change is not the only threat hanging over the head of humanity and nature. As nations keep proliferating nuclear weapons, with time the probability of a nuclear war increased exponentially. At the root of the MAD (mutual assured destruction) policy, or omnicide, resides the deep tribalism and herd mentality of the species, hinging on race, religion, ideology, territorial claims and an inherent concept of an “enemy” perpetrated by demagogues and warmongers, leading to an Orwellian 1984 world where “Oceania has always been at war with East-Asia”, as in the current “forever wars”. Prior to World War I two social forces collided, fascism and socialism. While the former is re-emerging the latter has weakened. At the core of superpower conflict between the Anglo-Saxon world and the Slavic or Chinese worlds are claims of moral superiority but in reality naked grabs for power which have obsessed civilizations since the Neolithic. At the core of human conscience is its mythological nature, a mindset closely related to the mastery of fire where, for longer than one million years, members of the species Homo erectus, perched at campfires (Fig. 14.15), watching the flickering flames, has grown its insights and imagination, developing a fear of death, dreaming of omniscience and omnipotence, aspiring for eternal life. As civilization developed since the Neolithic, the fear of death drove humans to construct pyramids to enshrine immortality, undertake human sacrifice to appease the gods through wars, leading to the ultimate sacrifice as expressed by Albert Einstein: “The splitting of the atom has changed everything bar man’s way of thinking and thus we drift into unparalleled catastrophes”. For an intelligent species to be able to explore the solar system planets but fail to protect its own home planet defies sanity. For a species to magnify its

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Fig. 14.15 The discovery of fire

entropic effect on nature, developing cerebral powers which allow it to become the intelligent eyes through which the Universe explores itself (Fig. 14.16), hints at yet undeciphered natural laws that underlie life and consciousness. Fig. 14.16 The Universe looking at itself through human eyes according to John Wheeler

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We have entered the age of consequences, masked by the 24 hours news cycle that can only portray transient events but rarely exposes the Orwellian mindset which underlies the powers-that-be. For, just as individuals can be plagued by insanity, so can groups or populations, as in the Jonestown massacre, or in Nazi Germany, where a nation or a species slide blindly into mass suicide, creating systems that saturate the atmosphere with carbon gases and proliferate nuclear weapons. According to the Fermi Paradox the failure to date to achieve radio communication between Earth and extraterrestrial civilizations can be attributed to their short longevity through their inherent self-destruction. Tragically Homo “sapiens” may not constitute an exception. The most extensive catastrophe in the history of Earth—the end-Permian- mass extinction 251 million years-ago, triggering atmospheric and marine warming, ocean acidification, toxic H2 S and CH4 emanations and anoxia, has led to a loss of some 57% of biological families, 83% of genera and 81% of marine species. Casualties of the current Anthropocene mass extinction may reach a similar order of magnitude. With a looming nuclear war on a rapidly heating greenhouse planet the collective suicide of an innovative yet unwise biped mammal, led by a moneydominated ideology implemented by cabals of corporations, billionaires and their mouthpieces, is tracking toward an extinction on a scale analogous to those of the end-Permian or the end-Cretaceous events, destroying its own civilization and taking a multitude of species down with it. Trying to survive on scorched and flooded terrains, or drowsing in front of celebrity-populated fluorescent TV and computer screens in suburbia international, the residents of planet Earth are perpetually bombarded by commercial and political advertising, trivial and parochial disinformation and infotainment, while most of the media diverts attention from the progressively degraded biosphere. As stated by Chomsky: “The smart way to keep people passive and obedient is to strictly limit the spectrum of acceptable opinion, but allow very lively debate within that spectrum….” Betrayal is everywhere. Contrary to the late twentieth century disarmament agreements are nowhere to be seen, while the power-to-be have decided to use force. False promises made before elections are routinely broken. $Trillions continue to be spent on the construction of ever deadlier weapons of mass destruction, war games, space games by the rich, gambling and entertainment, while nature is poisoned by greenhouse gases, acid water, insecticides, micro-plastics and radioactive waste. In a winner-take-all world the meaning of the term “defence” has been changed from the protection of life to the killing of manufactured “enemies”. In the core of human conscience is its mythological nature, a mindset springing from the mastery of fire where, for longer than one million years, members of Homo erectus, perched at campfire, watching the flickering flames, developed insights, imagination, a fear of death leading to dreams of omniscience and omnipotence, aspiring for eternal life.

References

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References American Museum of Natural History. Carl Sagan and the search for life. Cosmic Horizons. https:// www.amnh.org/learn-teach/curriculum-collections Bronselaer, B., et al. (2018). Change in future climate due to Antarctic meltwater. Nature, 564(8), 53–58. Carl Sagan and the search for life. Part of the cosmic horizons curriculum collection. https://www. amnh.org/learn-teach/curriculum-collections/cosmic-horizons-book/carl-sagan-quest-for-life Cielski, P. F. History of Planet Earth, University of Florida. National Geographic, BBC Nature. Robock, A., & Toon, O. B. (2012). Self-assured destruction: The climate impacts of nuclear war. Bulletin of the Atomic Scientists, 1 September, 2012. Schoene, B., et al. (2015). U-Pb geochronology of the Deccan traps and relation to the endcretaceous mass extinction. Science, 347(6218), 182–184.