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:
“Evidence of changes in the cryosphere in recent decades has been widely observed….
1) The duration of ice cover in rivers and lakes in high and middle latitudes of the Northern Hemisphere decreased by about two weeks over the twentieth century;
2) Significant retreat of glaciers worldwide during the twentieth century;
3) Decrease of Arctic Sea ice extent and thickness by about 40 percent in late summer in recent decades with the minimum sea ice concentration in 2007;
4) Reduction in snow-covered area in spring by about 10 percent since global observations began in the late 1960s;
5) Degradation of permafrost has been detected in parts of the polar and sub-polar regions.”
These themes have already been developed in the preceding chapters in some depth, but it is data like these, presented in a concise, factual and non-emotive way, that makes this book such a valuable resource.
Lastly, Part IV (one chapter) deals with applications of snow and ice research, and how humans interact with the cryosphere. These applications are many and varied, and include disruption resulting from snowfall and freezing rain, snow and ice avalanches, the winter sports industry and its probable decline, water resources and use of meltwater (such as in electricity generation), and the hazards and opportunities offered by the different components of the cryosphere. With plenty of examples, this is a fascinating chapter with which to end the book.
The writing style is clearly pitched at the level claimed, although I found the reference to past authors’ work mainly (but not always) in the present tense disconcerting, a style we advise our own students to avoid. The treatment of the topic is rigorous, with a good sprinkling of equations, although not at the expense of clarity for those students who may be “mathematically challenged”. Some chapters are heavy in their use of acronyms, so it is not always easy to ‘dip into’ the volume. There is the usual sprinkling of typographical errors, and some missing references and misspelt authors’ names, although with 100 pages of references, one can excuse a few of these.
I do feel the publishers have let down the authors somewhat in terms of illustrative material. There are potentially many useful figures, but maps are too small, and photographs lack sharpness and impact. All figures within the body of the text are in black and white, even when the originals are in colour, so many cannot be properly interpreted in situ. However, there is a collection of figures repeated in colour in a section in the middle of the volume, but this is inconvenient and the colour versions should have been included in the body of the chapters.
Despite these reservations, this book represents a superb effort by the authors, and they should be commended for bringing together so many facts and analyses concerning the state of the cryosphere. For those of us who are frequently challenged about the reality and impact of global warming, this book has many of the answers!