Life on our planet depends upon having a climate that changes within narrow limits – not too hot for the oceans to boil away nor too cold for the planet to freeze over. Over the past billion years Earth’s average temperature has stayed close to 14-15°C, oscillating between warm greenhouse states and cold icehouse states. We live with variation, but a variation with limits. Paleoclimatology is the science of understanding and explaining those variations, those limits, and the forces that control them. Without that understanding we will not be able to foresee future change accurately as our population grows. Our impact on the planet is now equal to a geological force, such that many geologists now see us as living in a new geological era – the Anthropocene. Paleoclimatology describes Earth’s passage through the greenhouse and icehouse worlds of the past 800 million years, including the glaciations of Snowball Earth in a world that was then free of land plants. It describes the operation of the Earth’s thermostat, which keeps the planet fit for life, and its control by interactions between greenhouse gases, land plants, chemical weathering, continental motions, volcanic activity, orbital change and solar variability. It explains how we arrived at our current understanding of the climate system, by reviewing the contributions of scientists since the mid-1700s, showing how their ideas were modified as science progressed. And it includes reflections based on the author’s involvement in palaeoclimatic research. The book will transform debate and set the agenda for the next generation of thought about future climate change. It will be an invaluable course reference for undergraduate and postgraduate students in geology, climatology, oceanography and the history of science. "A real tour-de-force! An outstanding summary not only of the science and what needs to be done, but also the challenges that are a consequence of psychological and cultural baggage that threatens not only the survival of our own species but the many others we are eliminating as well." Peter Barrett Emeritus Professor of Geology, Antarctic Research Centre, Victoria University of Wellington, New Zealand  "What a remarkable and wonderful synthesis... it will be a wonderful source of [paleoclimate] information and insights." Christopher R. Scotese Professor, Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA

Table of Contents:
Author Biography xi Acknowledgement xiii 1 Introduction 1 1.1 What is Palaeoclimatology? 1 1.2 What Can Palaeoclimatology Tell Us About Future Climate Change? 2 1.3 Using Numerical Models to Aid Understanding 4 1.4 The Structure of This Book 4 1.5 Why is This History Not More Widely Known? 6 References 7 2 The Great Cooling 9 2.1 The Founding Fathers 9 2.2 Charles Lyell, ‘Father of Palaeoclimatology’ 13 2.3 Agassiz Discovers the Ice Age 19 2.4 Lyell Defends Icebergs 22 References 28 3 Ice Age Cycles 31 3.1 The Astronomical Theory of Climate Change 31 3.2 James Croll Develops the Theory 33 3.3 Lyell Responds 35 3.4 Croll Defends His Position 36 3.5 Even More Ancient Ice Ages 37 3.6 Not Everyone Agrees 38 References 39 4 Trace Gases Warm The Planet 41 4.1 De Saussure’s Hot Box 41 4.2 William Herschel’s Accidental Discovery 41 4.3 Discovering Carbon Dioxide 42 4.4 Fourier, the ‘Newton of Heat’ Discovers the ‘Greenhouse Effect’ 43 4.5 Tyndall Shows How the ‘Greenhouse Effect’ Works 44 4.6 Arrhenius Calculates How CO2 Affects Air Temperature 47 4.7 Chamberlin’s Theory of Gases and Ice Ages 49 References 53 5 Changing Geography Through Time 57 5.1 The Continents Drift 57 5.2 The Sea Floor Spreads 63 5.3 The Dating Game 71 5.4 Base Maps for Palaeoclimatology 72 5.5 The Evolution of the Modern World 74 References 77 6 Mapping Past Climates 81 6.1 Climate Indicators 81 6.2 Palaeoclimatologists Get to Work 82 6.3 Refining Palaeolatitudes 86 6.4 Oxygen Isotopes to the Rescue 87 6.5 Cycles and Astronomy 88 6.6 Pangaean Palaeoclimates (Carboniferous, Permian, Triassic) 91 6.7 Post-Break Up Palaeoclimates (Jurassic, Cretaceous) 97 6.8 Numerical Models Make Their Appearance 104 6.9 From Wegener to Barron 110 References 110 7 Into the Icehouse 117 7.1 Climate Clues from the Deep Ocean 117 7.2 Palaeoceanography 118 7.3 The World’s Freezer 124 7.4 The Drill Bit Turns 126 7.5 Global Cooling 131 7.6 Arctic Glaciation 138 References 141 8 Greenhouse Gas Theory Matures 147 8.1 CO2 in the Atmosphere and Ocean (1930–1955) 147 8.2 CO2 in the Atmosphere and Ocean (1955–1979) 149 8.3 CO2 in the Atmosphere and Ocean (1979–1983) 161 8.4 Biogeochemistry: The Merging of Physics and Biology 166 8.5 The Carbon Cycle 167 8.6 Ocean Carbon 170 8.7 A Growing International Emphasis 173 8.8 Reflection on Developments 174 References 176 9 Measuring and Modelling CO2 Back Through Time 183 9.1 CO2 – The Palaeoclimate Perspective 183 9.2 Modelling CO2 Back Through Time 187 9.3 The Critics Gather 191 9.4 Fossil CO2 197 9.5 Measuring CO2 Back Through Time 199 9.6 CO2, Temperature, Solar Luminosity, and the Ordovician Glaciation 204 9.7 Some Summary Remarks 215 References 216 10 The Pulse of the Earth 223 10.1 Climate Cycles and Tectonic Forces 223 10.2 Ocean Chemistry 232 10.3 Black Shales 235 10.4 Sea Level 238 10.5 Biogeochemical Cycles, Gaia and Cybertectonic Earth 240 10.6 Meteorite Impacts 242 10.7 Massive Volcanic Eruptions and Biological Extinctions 246 10.8 An Outrageous Hypothesis: Snowball Earth 252 References 259 11 Numerical Climate Models and Case Histories 267 11.1 CO2 and General Circulation Models 267 11.2 Climate Sensitivity 270 11.3 CO2 and Climate in the Early Cenozoic 272 11.4 The First Great Ice Sheet 276 11.5 Hyperthermal Events 280 11.6 Case History – The Palaeocene – Eocene Boundary 282 11.7 Case History – The Mid – Miocene Climatic Optimum 287 11.8 Case History – The Pliocene 296 References 305 12 Solving the Ice Age Mystery – The Deep Ocean Solution 315 12.1 Astronomical Drivers 315 12.2 An Ice Age Climate Signal Emerges from the Deep Ocean 317 12.3 Flip-Flops in the Conveyor 324 12.4 Ice Age CO2 Signal Hidden on Deep Sea Floor 326 12.5 A Surprise Millennial Signal Emerges 327 12.6 Ice Age Productivity 331 12.7 Observations on Deglaciation and Past Interglacials 333 12.8 Sea Level 335 12.9 Natural Climatic Envelopes 337 References 338 13 Solving the Ice Age Mystery – The Ice Core Tale 345 13.1 The Great Ice Sheets 345 13.2 The Greenland Story 347 13.3 Antarctic Ice 350 13.4 Seesaws 354 13.5 CO2 in the Ice Age Atmosphere 362 13.6 The Ultimate Climate Flicker – The Younger Dryas Event 373 13.7 Problems in the Milankovitch Garden 374 13.8 The Mechanics of Change 377 References 395 14 The Holocene Interglacial 403 14.1 Holocene Climate Change 403 14.2 The Role of Greenhouse Gases – Carbon Dioxide and Methane 417 14.3 Climate Variability 427 References 432 15 The Late Holocene and the Anthropocene 437 15.1 The Medieval Warm Period and the Little Ice Age 437 15.2 Solar Activity and Cosmic Rays 455 15.3 Volcanoes and Climate 466 15.4 Sea Level 468 15.5 The End of the Little Ice Age 476 15.6 The Anthropocene 490 References 494 16 Putting It All Together 507 16.1 A Fast Evolving Subject 507 16.2 Natural Envelopes of Climate Change – Earth’s Thermostat 508 16.3 Evolving Knowledge 510 16.4 Where is Climate Headed? 515 16.5 Some Final Remarks 518 16.6 What Can Be Done? 520 References 523 Appendix 1: Further Reading 527 Appendix 2: List of Figure Sources and Attributions 529 Index 539