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Reviews August 2009

PhillipsGeological Fluid Dynamics

O M Phillips
Published by: Cambridge University Press
Publication date: 2009
ISBN: 978-0-521-86555-5
List price: £40.00
285 pp 

Geological fluid dynamics (GFD) is not a new field, but there is a scarcity of books on the subject. Owen Phillips’ volume fills this void with an excellent text that will likely become a mainstay in graduate courses in environmental fluid mechanics, hydrogeology, geophysics and petroleum geology. The sub-title ‘Sub-surface Flow and Reactions’ is more representative of the content of the book than the title. Rather than covering diverse GFD topics such as turbidite flows, CO2 sequestration, and dynamics of volcanic eruptions, the text focuses on groundwater flow (constant and variable density) and reactions. This said, it is definitely not a ‘typical’ hydrogeology text.

With an obvious emphasis on fluid mechanics and mathematics, the reader requires a good understanding of engineering mathematics to comprehend the subject matter. This is an area where Phillips’s style and clarity of writing are especially apparent, with lucid explanations of the basic physical principles of groundwater flow. Coming from a hydrogeology background I found some of the terminology confusing. Phillips refers to ‘surface aquifers’ – I wasn’t sure if this meant a shallow aquifer or an unconfined aquifer. In other places there is redundant terminology where Phillips refers to the ‘unsaturated vadose zone’ (unsaturated zone) and the ‘water-saturated region’ (saturated zone). This confusion probably stems from the interdisciplinary nature of GFD, with each interest group having its own language.

This text places more emphasis on the fluid dynamics than the geology, and as such its readership will lean towards numerically minded Earth scientists and modellers. If you have Jacob Bear’s Dynamics of Fluids in Porous Media on your bookshelf, you will welcome this new text next to it. For those readers coming from a more traditional geological background I suggest starting with Groundwater in Geologic Processes (Steven Ingebritsen, Ward Sanford and Christopher Neuzil).

Graduate students and researchers will benefit most from this book, which contains the distilled knowledge of a lifetime’s work of one of the leading practitioners in this field. Given the subject matter (environmental fluid mechanics, hydrogeology, geophysics and petroleum geology), it is apparent that this text is a cross-disciplinary work that will benefit and be well received by a wide audience. The quality of the paper, printing, and binding is excellent, and at £40 it is reasonably priced. If this book is purchased for a graduate course, I see no reason why it should not survive a lifetime of use.

Matthew Waterman

Battarbee et alNatural Climate Variability and Global Warming: A Holocene perspective

Richard W Battarbee and Heather A Binney (eds)
Published by: Wiley-Blackwell
Publication date: 2008
ISBN: 978-1-4051-5905-0
List price: £55.00
276 pp

‘Prediction’, as Neils Bohr once said, ‘is very difficult, particularly about the future’. This beautifully produced collection of papers might have been assembled to prove his point. From Milankovitch cycles to solar variability, volcanic activity, the ocean-atmosphere system and the impact of man, this volume documents the bewildering complexity of the Holocene climate. Although aimed at ‘researchers and advanced students’, this layman found the book perfectly accessible.

John Birks offers us a potted history of Holocene research, which demonstrates that change has been the norm over the past 11,500 years. Frank Oldfield reminds us that people are part of the climate system, not passive recipients. But although major changes in land use began at least 8000 years ago, man’s impact on climate prior to the 20th Century remains controversial. Michel Crucifix outlines the challenges for climate models, including stochastic events that could produce sudden changes with no identifiable cause. He is less reticent than Oldfield about man’s impact, making the intriguing suggestion that anthropogenic activity may have delayed the next ice age! Jansen et al. link the Holocene thermal maximum to orbital forcing, and identify multi-century to millennial internal variability in the climate system. Beer and van Geel demonstrate the importance of solar forcing amplified by positive feedbacks. Standard climate models may under-estimate this forcing.

Verschuren and Charman note that changes in rainfall have a profound impact on human welfare. They show that hydrological changes may be correlatable over large distances. Martin Claussen shows that subtle forcings can produce dramatic changes in land cover; the rapid expansion of the Sahara about 5500 years ago being the prime example. Summarising, Raymond Bradley notes that people do not experience mean climate conditions, they are subject to regional climatic variability. Models for predicting such potentially catastrophic variability are urgently needed.

Despite the high quality of individual chapters I have two reservations about the book. First, it doesn’t really do ‘what it says on the tin’. The claim that it ‘provides the groundwork for making critical decisions about the earth’s future’ is not substantiated by the content - the book has nothing specific to add to current projections of 21st Century warming. Secondly, the insistence that recent decadal-scale global temperature rise has been definitively explained is unsubstantiated and somewhat ‘forced’ in a volume that scarcely addresses this period. However, the rehabilitation of the Medieval Warm Period and Little Ice Age will delight traditionalists, and give some comfort to critics who doubt climate-science’s capacity for self-correction.

Joe Brannan
The Hague

Per Kirkeby The Siege of Constantinople 1995 Tate © The artist. Oil on canvas 400 x 340 cm.Per Kirkeby

Tate Modern
17 June – 6 September
Sunday to Thursday, 10.00–18.00. Friday and Saturday, 10.00–22.00
Last admission 17.15 (Friday and Saturday 21.15)
£9.80 (Concs £7.80/Senior £8.80/Family £24.50 concessions)

For as long as nature has appeared in art, geology and painting have had a close relationship. Leonardo da Vinci, the ultimate polymath, made detailed observations of his geological surroundings, reproduced in some of his most famous paintings, while the Pre-Raphaelites took careful note of the most fashionable science of their time.

There are far fewer examples of things working in the other direction. Considering geologists are famous for their colouring-in abilities, this is perhaps surprising. Per Kirkeby, who has been called one of Denmark’s most ‘internationally acclaimed artists today’ is a notable exception. Having studied for a masters in Arctic geology at the University of Copenhagen, Kirkeby has gone on to embrace numerous fields, including painting, sculpture and writing, in a career outlined in a new exhibition at Tate Modern.

Kirkeby’s influences are as diverse as his background. Ranging from pop culture to the Byzantine Empire, they rarely result in paintings that depict nature directly, as might be expected. Instead, there are huge canvases of abstract shapes and scribbles, scrawls on blackboards, bronze architectural sculptures. His constant theme seems to be a search for patterns, suggesting that something coherent might exist among the apparently random lines and brush strokes. It is here that the influence of a geological training seems to have lingered.

Kirkeby’s palette, too, reflects his interest in nature - predominantly greens and browns and greys, these may not be the kind of paintings you would necessarily want in your home. To me, the most conventionally attractive are also the least abstract – a series of watercolours painted on field trips to Greenland depicting fleeting impressions of coastlines, glaciers and mountains. Here, the exhibition notes make much of Kirkeby’s ‘scientific eye’: “While rooted in his scientific training, they are ultimately structured by their own painterly logic of colour and line”. The implication seems to be that this side of the works remains unscientific, because it is less apparently controlled.

Other text in the exhibition also suggests division between these two sides of Kirkeby’s training, proclaiming that he approaches his diverse range of subjects with a “sense of curiosity and enquiry, whose near-scientific rigour can be traced back to the artist’s original university training as a geologist”. His ‘painterly response’ to nature is thus contrasted with the apparently simple act of observation.

In Kirkeby, the art world has found an unusual subject – a scientist – and reacted as one might expect, by searching for aspects that can be labelled ‘scientific’. Kirkeby, we are told, struggles to reconcile these two ways of seeing. This may be true, one can’t help thinking that the argument might be more convincing had he originally trained as a physicist. Geologists are quite used to dealing with apparent chaos. Their observations are rarely untouched by (constrained) imagination. And, as examples like da Vinci demonstrate, rigorous observation of nature is not only of use to, or characteristic of, scientists.

It seems unnecessary to draw attention to the distinction. Kirkeby’s art, while occasionally monotonous and overworked, provides a fascinating insight into how science and art can work together to reflect on nature and our place in it. As the painter himself writes: ‘the world is a material of which one makes art’. A statement that is equally true of science.

Sarah Day