The global cryosphere: past, present and future

The term cryosphere, according to this excellent new volume, is derived from the Greek word kryos for icy cold, which collectively describes the frozen parts of the Earth’s surface, including sea ice, lake ice, river ice, snow cover, glaciers, ice sheets, and frozen ground. This volume is a major contribution to our understanding of the cryosphere, by combining the authors’ first-hand knowledge of the issues and presenting a synthesis of a vast range of published literature. The publishers claim that this is the first textbook to address all components of the cryosphere, by providing a concise, but comprehensive summary of cryospheric processes for upper-level undergraduates and graduates in environmental science, geography, geology, glaciology, hydrology, water-resource engineering and ocean sciences. They claim also to provide a superb up-to-date summary of cryospheric processes for researchers from a range of sciences. To evaluate these claims, this review outlines the key components of the book, and considers how well the book has been assembled. First, it is worth noting the credentials of the authors. Roger Barry was formerly Director of the World Data Centre for Glaciology and Professor of Geography at the University of Colorado at Boulder. He is a leading authority on climate change, Arctic and mountain environments, and snow and ice processes. He is the recipient of several awards and medals, including the Founder’s Medal of the Royal Geographical Society. T.Y. Gan is a Professor at the University of Alberta with interests in snow hydrology and climate change impacts. These authors are thus well placed to summarize the state-of-the-art, now that it has become widely recognized that the cryosphere represents a critical and sensitive component of the Earth System, especially in the context of global warming. The book has four parts, subdivided into eleven chapters. The first two parts cover the terrestrial and marine cryosphere. Focussing on historical background, characteristics, distribution, physical processes, numerical modelling and cross-linkages the treatment is wide-ranging, with a chapter for each of these cryosphere components. These chapters are full of fascinating facts; I was particularly impressed with the brief historical treatments of each topic. There are, however, some notable gaps, and the claim to ‘address all components of the cryosphere’ is an exaggeration. For example, in the Glaciers and Ice Caps chapter, I found it surprising that there was little mention of glacial erosional and depositional processes, surely a key aspect of interpreting past cryospheric processes? Similarly, several aspects of the attributes of glaciers, such as glacier flow, are treated in a superficial and unbalanced fashion but the authors do refer to some of the key texts that address related topics more rigorously. Part III deals with the past history and future of the cryosphere. Given the volume of research on past glacial history, no single book, let alone the one short chapter here, can do justice to this topic, and I did not see reference to many of the key monographs and textbooks dealing with Quaternary and older glaciations. Readers of this chapter will not get a particularly balanced view of our understanding of past cryospheric changes. In contrast, the paired chapter on recent and future changes in the cryosphere is much more valuable, combining recent observations with predictions of global impacts based on IPCC scenarios. Indeed, it is worth summarizing what these recent changes have been (Chapter 10.3). To quote: