Studying past climate change offers a valuable way of observing how the climate system responds to natural forcings. Ice cores from the polar regions are an excellent tool for investigating past climate, in part thanks to the unique archive of atmospheric air preserved in the glacial ice. The most abundant components of this air are, of course, nitrogen, oxygen, and argon, each of which records valuable information about past climate. This thesis explores the climate of the Last Glacial Period using measurements of the isotopic composition of nitrogen, oxygen, and argon in ice core air.Chapter 2 discusses fluctuations in the properties of the snow and firn at the South Pole during the past 30,000 years. The largest fluctuations are the result of past changes in katabatic wind speed linked to variations in surface topography upstream of the ice core site. In addition, the data, together with a series of modelling experiments, provide evidence that the ice core data are affected by a seasonal bias. The bias is also linked to past wind speed and topography at the ice core site and has the potential to impact other, similar ice core records. Chapter 3 utilizes ice core records of the isotopic composition of atmospheric oxygen to investigate the response of tropical hydroclimate and the terrestrial biosphere to abrupt climate change during the Last Glacial Period (Dansgaard-Oeschger and Heinrich Events). The data show that tropical precipitation and global photosynthetic oxygen production migrate northward and southward in response to abrupt warming and cooling in the North Atlantic, taking approximately 1,000 years to adjust to the new climate state. Chapter 4 presents an improved analytical method for making precise measurements of the isotopic and elemental ratios of nitrogen, oxygen, and argon in whole-air (i.e., without splitting or purifying the ice core air sample). The results are (i) a method capable of measuring the three gases with a precision suitable for detecting ice core signals, and (ii) recommendations for further development and application of the method to ice core samples. In sum, the findings presented here advance our understanding of how wind-speed and topography affect ice core gas records, how tropical hydroclimate and the terrestrial biosphere respond to abrupt climate change, and how to better make precise measurements of these gases in ice core samples.

The Great Ice Age documents and explains the natural climatic and palaeoecologic changes that have occurred during the past 2.6 million years, outlining the emergence and global impact of our species during this period. Exploring a wide range of records of climate change, the authors demonstrate the interconnectivity of the components of the Earths climate system, show how the evidence for such change is obtained, and explain some of the problems in collecting and dating proxy climate data. One of the most dramatic aspects of humanity's rise is that it coincided with the beginnings of major environmental changes and a mass extinction that has the pace, and maybe magnitude, of those in the far-off past that stemmed from climate, geological and occasionally extraterrestrial events. This book reveals that anthropogenic effects on the world are not merely modern matters but date back perhaps a million years or more.

An exciting account of revolutionary new discoveries for understanding the earth's climate, and their implications for future scientific research and global environmental policy.

This book studies the history and gives an analysis of extreme climate change on Earth. In order to provide a long-term perspective, the first chapter briefly reviews some of the wild gyrations that occurred in the Earth’s climate hundreds of millions of years ago: snowball Earth and hothouse Earth. Coming closer to modern times, the effects of continental drift, particularly the closing of the Isthmus of Panama are believed to have contributed to the advent of ice ages in the past three million years. This first chapter sets the stage for a discussion of ice ages in the geological recent past (i.e. within the last three million years, with an emphasis on the last few hundred thousand years). The second chapter discusses geological evidence for ice ages – how geologists surmised their existence prior to actual subsurface data that proved the theory. The following two chapters look at ice cores (primarily from Greenland and Antarctica). Chapter 3 discusses how ice core data is processed and Chapter 4 summarizes data obtained from ice cores. Chapter 5 discusses the processing of data obtained from ocean sediments, and summarizes the results, while the following chapter discusses data from other sources, such as "Devil’s Cave." Chapter 7 summarizes the experimental results from Chapters 4, 5, and 6. It provides the foundation for comparison with theories in later chapters. In a perfect world, this data would be totally separate and disconnected from theory. Unfortunately, as the author shows, dating of much of the data was accomplished by "tuning" to the astronomical theory, which introduces circular reasoning. Chapter 8 provides a brief overview of the various theories that have been devised to "explain" the patterns of alternating ice ages and interglacials that have occurred over the past three million years. This serves as an introduction to the following three chapters which presents the astronomical theory in its various manifestations, compare the astronomical theory with data, and then compare other theories with data. Finally, Chapter 12 summarizes what we think we know about ice ages and, more importantly, what we don’t know.

Earth's climate varies continuously across space and time, but humankind has witnessed only a small snapshot of its entire history, and instrumentally documented it for a mere 200 years. Our knowledge of past climate changes is therefore almost exclusively based on indirect proxy data, i.e. on indicators which are sensitive to changes in climatic variables and stored in environmental archives. Extracting the data from these archives allows retrieval of the information from earlier times. Obtaining accurate proxy information is a key means to test model predictions of the past climate, and only after such validation can the models be used to reliably forecast future changes in our warming world. The polar ice sheets of Greenland and Antarctica are one major climate archive, which record information about local air temperatures by means of the isotopic composition of the water molecules embedded in the ice. However, this temperature proxy is, as any indirect climate data, not a perfect recorder of past climatic variations. Apart from...

Antarctic Climate Evolution, Second Edition, enhances our understanding of the history of the world’s largest ice sheet, and how it responded to and influenced climate change during the Cenozoic. It includes terrestrial and marine geology, sedimentology, glacier geophysics and ship-borne geophysics, coupled with results from numerical ice sheet and climate modeling. The book’s content largely mirrors the structure of the Past Antarctic Ice Sheets (PAIS) program (www.scar.org/science/pais), formed to investigate past changes in Antarctica by supporting multidisciplinary global research. This new edition reflects recent advances and is updated with several new chapters, including those covering marine and terrestrial life changes, ice shelves, advances in numerical modeling, and increasing coverage of rates of change. The approach of the PAIS program has led to substantial improvement in our knowledge base of past Antarctic change and our understanding of the factors that have guided its evolution. Offers an overview of Antarctic climate change, analyzing historical, present-day and future developments Provides the latest information on subjects ranging from terrestrial and marine geology to sedimentology and glacier geophysics in the context of Antarctic evolution Fully updated to include expanded coverage of rates of change, advances in numerical modeling, marine and terrestrial life changes, ice shelves, and more

The second revised edition of the Encyclopedia of Quaternary Science, Four Volume Set, provides both students and professionals with an up-to-date reference work on this important and highly varied area of research. There are lots of new articles, and many of the articles that appeared in the first edition have been updated to reflect advances in knowledge since 2006, when the original articles were written. The second edition will contain about 375 articles, written by leading experts around the world. This major reference work is richly illustrated with more than 3,000 illustrations, most of them in colour. Research in the Quaternary sciences has advanced greatly in the last 10 years, especially since topics like global climate change, geologic hazards and soil erosion were put high on the political agenda. This second edition builds upon its award-winning predecessor to provide the reader assured quality along with essential updated coverage Contains 357 broad-ranging articles (4310 pages) written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource for information in the field. Facilitates teaching and learning The first edition was regarded by many as the most significant single overview of Quaternary science ever, yet Editor-in-Chief, Scott Elias, has managed to surpass that in this second edition by securing even more expert reviews whilst retaining his renowned editorial consistency that enables readers to navigates seamlessly from one unfamiliar topic to the next