Book Reviews

book reviews

Crop Yields and Climate Change to the Year 2000, Volume I. By the questionable record in facing up to regional droughts with that tech- Research Directorate of the National Defense University. 1980. nology. While the study does consider a spectrum of annual cli- 128 pages, n.p. Paperbound. U.S. Government Printing Office, mates, it does not consider runs of extreme years which often lead to Washington, D.C. serious regional droughts and economic upsets. The elements of the report are well prepared and presented, but This innovative work will interest a wide audience, particularly their assembly and frequent references to important materials in among those concerned with the future capability of the world's other volumes tend to break reading continuity. A foreword, ab- agriculture to meet changing societal needs and changing climates. stract, preface, and summary precede the chapters of the report. The report is identified as the second phase of a climate impact Each is well done, and collectively they provide the setting for this assessment. Its purpose is to show how major world crop yields volume and help serve the dichotomous readership for which the re- would be affected by specified climate changes, assuming constant port is intended. The preface and summary state the problem, back- agricultural technology. It is a companion study to others which as- ground methodology, and results in a manner that will interest sess the nature of possible climate changes and the policy implica- policy-oriented and general readers. The ensuing chapters are more tions of related altered productivity. The combined effort is a sig- technical, detailing methodology, technology, and yields obtained nificant contribution to the development of impact assessment for different scenarios as model output. Not surprisingly, the pro- methodology. jected climate changes were found to have their greatest impacts in Climate impact studies are complex, involve many disciplines, and northern or middle latitudes, with Soviet and Canadian wheat being generally relate to policy formulation. Crop Yields and Climate most influenced. Over the globe both winners and losers are pro- Change to the Year 2000 is a complex study which involved broad jected; for example, with a cooling climate the yields of wheat are expertise from governments and universities. In a preceding study, reduced in five countries and increased in four. Climate Change to the Year 2000, 24 leading climatologists contrib- The methodology involves the derivation of bivariate distribu- uted to the formulation of five global climate scenarios. The present tions of temperature during the heading period and of precipitation study exploits the wisdom of 35 agricultural experts in assessing how for the crop year for the countries and crop scenarios in question as the selected climate scenarios would influence the yields of five prin- well as for a base period. These are used in conjunction with the cli- cipal crops within eight producing countries. To do this it was neces- mate-crop yield relationships implied in the expert opinions to assess sary to develop procedures to quantify the various expert opinions alterations in yield and to assign probabilities of occurrence for spe- on yield-weather relationships, evaluate the effects of technology, cific precipitation/temperature occurrences within a scenario. Sta- and make weighted interpretations of model outputs. The magni- tistics are provided to show the probable spectrum of yields to be tude of this task necessitated the use of many simplifying assump- experienced within each climate scenario. tions. The authors list many caveats, noting in particular that one Many interpretations follow from the model results. Precipitation might criticize the failure of the model to account for all the compli- is shown to be of critical importance, a 10% change generally alter- cations of real life. Had the study attempted to do so, completion ing yields more than either of the large cooling or warming scenarios would have been virtually impossible. Probably the greatest success selected for analysis. The projection of technological trends indi- in the report is the crunching down of large and complex problems cates that climate changes are unlikely to be detectable from yield into digestible yet credible quantities. The interpretation or wording statistics because of the overriding effects of technology and short- of the results and the lack of a clear-cut position concerning climate term climate variations on these values. fluctuations will raise many questions in the minds of readers. The In short, the study presents a powerful tool for the assessment of authors stress that the "discussion concerns not fact but the output the food security aspects of climate change. The designers are to be and behavior of a climate response model," but many conclusions complimented on the manner in which they have brought great di- are presented in a manner that does not demonstrate this caution. versity of opinion together in this model synthesis. The next step is Consider the claim that "technology, rather than climate is likely to the application of the methodology or concepts developed in the re- be the chief determinant of production levels to the year 2000." This port. Further development of the methodology also is required to comparison is reasonable for gradual climate change, but perhaps overcome the aforementioned limitations of methods and results. not too meaningful in actual operations where climate and tech- These steps and additional research into the interactions of climate nology are not competitors but complementary within a total sys- and technology will be greatly facilitated by the appearance of this tem. The case of Australian wheat yield projections illustrates this report.—Gordon A. McKay and G. D. V. Williams point. It is suggested that this case is anomalous because "Australian growing conditions discourage investment in technology inputs." Gordon A. McKay is the Director of the Climatological Applications This is tantamount to saying that climate constraints can be so great Branch at the Canadian Climate Centre; G. D. V. Williams is an Agro- that yield improvements are difficult to achieve with reasonable climatologist at the Canadian Climate Centre, Downsview, Ontario. technological investments. In that case climate is the determinant. The climate of the 1970s created serious, legitimate concerns about food security. Projections of the increasing demand for food, compe- tition for water and energy, and a decreasing soil capability are serious potential constraints to realizing technological projections. Technology has greatly expanded productivity, but mankind has a

Bulletin American Meteorological Society 427 428 Vol. 63, No. 4, April 1982

Evolution of Physical Oceanography: Scientific Surveys in Honor of Baker; a valuable survey of geochemical tracers and their use in Henry Stommel. Edited by Bruce Warren and Carl Wunsch. 1981. ocean circulation by Wallace Broecker; and an excellent summary of 623 pp. $37.50. Hardbound. The MIT Press, 28 Carleton St., laboratory models and their role in the development of our under- Cambridge, Mass. 02142. standing of ocean dynamics by Allan Faller. Part IV contains only two chapters: a brief account of air-sea in- Here under one cover is a monumental synthesis of 18 topical sur- teraction by Henry Charnock which deals primarily with the classi- veys bearing on the evolution and present state of the art in the diag- cal momentum transfer problem; and a lengthy discussion of oceanic nostic, experimental, and theoretical aspects of physical oceanog- analogues of large-scale (and mesoscale) atmospheric motions by raphy. It represents the combined efforts of 26 contributors from Jule Charney and Glenn Flierl. This last chapter will be of particular Arons to Veronis, including reviews by its co-editors Warren and interest to meteorologists and physical oceanographers alike. It is a Wunsch, in tribute to Henry Stommel. The themes, as promised in systematic and thorough cataloguing of the similarities and differ- the co-editors' preface and implied by the title, are: to trace the de- ences in the dynamics of the ocean and atmosphere from a modern velopment of the important aspects of the field from the pre- point of view. This last chapter is truly outstanding and a fitting final Stommel era to the present; to describe in specific terms our under- work by its late senior author. standing of these subjects now; and to identify what seem to be some Overall, Evolution of Physical Oceanography should prove to be a key questions for the future. The contributions in this volume, with text of longstanding value for graduate instruction as well as a valu- few exceptions, live up to these expectations. able reference for oceanographers and meteorologists.—Robert O. Some notion of the scope of this work is gained by perusing its Reid nearly 2000 selected references. Of particular interest to this reviewer is the fact that over half (1044) of the references are from the 1970s; Robert O. Reid is Head of the Department of Oceanography, Texas of the remainder, 426 are from the 1960s, 191 from the 1950s, and A&M University, College Station, Tex. 245 prior to 1950. Viewed as a whole, the work traces the development of the field from the early contributions by the Scandinavian school at the turn of the century, continuing with the era of ocean exploration through the 40s, the beginnings of the theoretical renais- sance in the late 40s in which Stommel played a leading role, then on to the beginnings of serious numerical and physical modeling experiments in the 60s, and culminating with the present era of emphasis on the mesoscale, fine structure, and strategic experiments in the real ocean and in the simulated ocean of the modelers. Primary emphasis Spaceborne Synthetic Aperture Radar for Oceanography. The Johns is on the developments since the publication of The Oceans (H. U. Hopkins Oceanographic Studies, number 7. Edited by Robert C. Sverdrup, M. W. Johnson, and R. H. Fleming, Prentice-Hall, 1942). Beal, Pat S. DeLeonibus, and Isadore Katz. 215 pages. $19.50. The work leads off with a chatty sequence of reminiscences about Hardcover. The Johns Hopkins University Press, Baltimore, Md. Henry Stommel by five of his close associates, A. B. Arons, G. Vero- 21218. nis, R. B. Montgomery, G. E. R. Deacon, and F. C. Fuglister. The main text contains four parts: I, dealing with both descriptive and To those readers familiar with the Johns Hopkins Oceanographic theoretical aspects of ocean circulation; II, dealing with physical Studies, Volume 7 may appear to be a bit of an anomaly. Five of the processes and transient phenomena at small and large scale; III, first six volumes are monographs, while this treatise is an edited ver- dealing with techniques of investigation; and IV, dealing with ocean sion of papers (and discussions) presented at a symposium in 1980. and atmosphere interaction and analogies. Notwithstanding, the editors have ably and successfully undertaken Part I is quite comprehensive and could well serve as a graduate the monumental task of organizing these proceedings into a coher- text on the subject of ocean circulation. Bruce Warren addresses the ent collection of information worthy of publication within the Johns subject of deep circulation, Joe Reid the mid-depth circulation, Nick Hopkins Oceanographic Studies. The intent of the symposium, and Fofonoff the Gulf Stream system, and Val Worthington the water consequently of this volume, is to provide an objective assessment of masses of the world ocean. These chapters are followed by a discus- what has been accomplished in the application of synthetic aperture sion of dynamics of large-scale ocean circulation by George Veronis; radar (SAR) to oceanographic problems, and to define a focus and equatorial currents by Ants Leetmaa, Julian McCreary, Jr., and direction for researchers working with this instrument. Dennis Moore; and shelf and estuarine circulation by Bob Beardsley The volume is divided into five major sections and additionally in- and Bill Boicourt. The latter two chapters are rather brief compared cludes front matter and an appendix containing photographic re- with similar reviews of these subjects in the literature, but they do productions of a significant portion of the SEASAT SAR imagery address the key questions. from the western North Atlantic Ocean. The front matter will be in- In Part II the subject of small-scale mixing processes is addressed dispensible to those readers who are unfamiliar with SEASAT and by J. S. Turner, and vertical convection by Willem Malkus. A lucid the SAR. A foreword places the symposium and its proceedings in discussion of the dynamics of internal waves and small-scale process proper perspective, while a well-written introduction describes in and what we know about their spectra is given by Walter Munk. elementary terms the fundamentals of radar aperture synthesis and Long waves and ocean tides and their relevance to the rest of ocea- the characteristics and operation of the SEASAT SAR in particular. nography are addressed by Myrl Hendershott. The subject of low- Four of the five major sections of the proceedings were chosen to frequency variability and the role of eddies in ocean dynamics is highlight some of the more promising potential applications of the covered in a thought-provoking account by Carl Wunsch. A brief SAR to oceanography. Section I, Air-Sea Interactions and the SAR, chapter by John Steele addresses biological patchiness and its contains three papers and serves as a basis for interpreting and un- relevance. derstanding the balance of the volume. Sections II and III each con- Part III includes three very pertinent surveys: a comprehensive tain three papers and are entitled Wind and Waves, respectively, discussion of ocean instruments and experiment design by Jim while Section IV treats Circulation and contains four papers dealing