the goldilocks planet This page intentionally left blank the four billion year story of earth’s climate goldilocks THE planet JAN ZALASIEWICZ & MARK WILLIAMS (cid:20) 3 Great Clarendon Street, Oxford ox2 6dp Oxford University Press is a department of the University of Oxford. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide in Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offi ces in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries Published in the United States by Oxford University Press Inc., New York © Jan Zalasiewicz and Mark Williams 2012 The moral rights of the authors have been asserted Database right Oxford University Press (maker) First published 2012 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, or under terms agreed with the appropriate reprographics rights organization. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above You must not circulate this book in any other binding or cover and you must impose the same condition on any acquirer British Library Cataloguing in Publication Data Data available Library of Congress Cataloging in Publication Data Data avialable Typeset by SPI Publisher Services, Pondicherry, India Printed in Great Britain on acid-free paper by Clays Ltd, St Ives plc ISBN 978–0–19–959357–6 10 9 8 7 6 5 4 3 2 1 To Asih, Kasia, Mateusz, Milana This page intentionally left blank Contents Acknowledgements i x List of Illustrations x i Prologue xiii A Brief Word on Time xvii 1. Primordial Climate 1 2. Earth as a Snowball 21 3. Between Greenhouse and Icehouse 53 4. The Last Greenhouse World 85 5. The Ice Returns 107 6. The Last of the Warmth 133 7. Into the Icehouse 157 8. The Glacial World 169 9. Birth and Death of the Holocene 199 10. The Anthropocene Begins 229 Notes 2 69 Further reading 279 References 2 81 Index 297 vii This page intentionally left blank Acknowledgements This book grew out of a long-held interest we both have in trying to work out what the world used to be like in olden times—in the days of our human ancestors, and in those nigh-countless days before humans evolved, when the world was very different. What did much to determine the nature of those prehistoric worlds, we have found, was climate. Not so much in whether any particular pri- mordial landscape was delicately sun-kissed, or grey and misty, or windy and rain-swept. That is part of it, of course, but the effect of climate is far more fundamental. It governs the balance between land and sea, the shape of the landscape, the pattern of sea currents —and the nature of living communities. Hence this exercise in tell- ing the story of Earth’s climate—from its beginnings to its chang e- able present and uncertain future. This book has been supported by those at Oxford University Press, who have patiently and amiably converted a rather untidy assortment of words and pictures into a proper book, with Latha Menon’s perceptive editing in particular steering the narrative into shape. Our thanks, too, to colleagues who have read all or part of the narrative, and/or who have provided information or illustra- tions: Harry Dowsett, John Smellie, Steve Hesselbo, Euan Nisbet, Ian ix