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.
Paleoclimatology: From Snowball Earth to the Anthropocene 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.
Author Biography xi
1 Introduction 1
2 The Great Cooling 9
3 Ice Age Cycles 31
4 Trace Gases Warm The Planet 41
5 Changing Geography Through Time 57
6 Mapping Past Climates 81
7 Into the Icehouse 117
8 Greenhouse Gas Theory Matures 147
9 Measuring and Modelling CO2 Back Through Time 183
10 The Pulse of the Earth 223
11 Numerical Climate Models and Case Histories 267
12 Solving the Ice Age Mystery – The Deep Ocean Solution 315
13 Solving the Ice Age Mystery – The Ice Core Tale 345
14 The Holocene Interglacial 403
15 The Late Holocene and the Anthropocene 437
16 Putting It All Together 507
Appendix 1: Further Reading 527
Appendix 2: List of Figure Sources and Attributions 529
Colin P. Summerhayes is an Emeritus Associate of the Scott Polar Research Institute of Cambridge University. He has carried out research and managed research programmes on aspects of past climate change in academia, in government laboratories, in intergovernmental and non-governmental organizations, and in industry since obtaining a PhD in Geochemistry from Imperial College, London, in 1970.