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The Earth's climate: Past and future
256
BOOK REVIEWS
tice to the large Central Volcanic Region with lucid treatments of ignimbrite sheets and central eruptive structures which vary in form with petrology. Neal1 on Taranaki gives useful detail on large and.small volcanic landforms on and around Mt. Egmont in one halfchapter. The other half discusses Taranaki’s inland hilly terrain and its coastal Quaternary marine terraces, and would better have been part of Heerdegen’s following chapter on neighboring Manawatu. In itself, Heerdegen’s chapter is a highly informative. well-organized discussion of the Tertiary upland denudation surface, Quaternary uplifted marine terraces, terraced alluvial tills, and multiple sheets of near-coastal dunes. Kamp on Hawke’s Bay. Kamp and Vucetich on the Wairarapa, and Eyles on Wellington excellently cover eastern and southeastern North Island. making optimal use of plate-tectonic context. In these areas, northwesterly oblique subduction of the Pacific Plate has produced northeast-trending geomorphic zones founded on back-thrust sheets. laced with dextral transcurrent faults, in a former forearc basin. Across Cook Strait. Nelson and Marlborough provinces in northern South Island lie partly within a direct extension of this tectonic environment, so that Campbell and Johnston’s emphasis here is similarly on tectonic landforms. Their map of the region may be the first dot-map to show elevation without boundaries between elevation classes, and it fails totally in its purpose. A full rather than half-page map of this region could have usefully classified tectonic landforms and showed the extent of the Tertiary denudation surface. Soons reviews Westland, between the crest of the Southern Alps and the Tasman Sea coast of South Island, emphasizing tectonic features (particularly the Alpine Fault trace) and glaciation. Little departure is made from traditional concerns and approaches. This may reflect the dual audience. but glaciated, tectonically active alpine zones in general have not easily lent themselves to dynamic geomorphic synthesis. The large size of this area also makes its geomorphic features difficult to present on page-length maps (I :2,000,000 scale). Bell’s long chapter on the geomorphic evolution of the Kawarau Valley. Otago, is anomalous as a case study in this book. Informative though it is. it takes up a disproportionate 25 pages, some of which could have done more justice to wider Otago. The geomorphic integrity of this province, with its tor-dotted Tertiary land surface and its gradient from glacial to periglacial Pleistocene morphodynamics, deserves a broader treatment on a par with other regions. Its absence from the book is a surprise, considering the amount of previous work. some very recent. Fitzharris ef crl. lump together South Island’s diverse basins and lowlands as areas where depositional surfaces predominate. Individual authors treat Canterbury Plains (Soons), Mackenzie Basin (Mansergh). and Southland Lowland (Fitzharris) as examples of responses to post-erogenic sedimentation in contrasting tectoniciphysiographic settings, modulated by
glacial/nonglacial morphogenetic cycles. Major late Quaternary deposits and surfaces deserve a correlation chart which would have better held this chapter together. In detail, I quibble with their nonconsideration of stream piracy as a major influence on the location of gorges linking tectonic basins. particularly when evidence for superposition and antecedence is not discussed. A final chapter by McKellar rather too sketchily summarizes Fiordland’s geomorphology. This is more of an interpretation of scenery for laymen. An opportunity is missed to contrast glacial style with that of the Southern Alps. and little is offered on the features for which the region is named. “Landforms of New Zealand” is handsomely produced in 18 x 24-cm format, on robust stock, with clear type and amazingly few typographical and layout errors. Illustrations are profuse: fully 20% of the book is occupied by photographs, the majority near halfpage size. Those produced from color transparencies are distinguished by slight fuzziness only because the original black-and-white ones are so crisp. Annotation with arrows and other symbols would have enhanced their utility. Stereo pairs are conspicuous by their absence. References follow each chapter and are current to 1981 in (only) three chapters. Many are relatively inaccessible to overseas readers and some are given as theses, where the derived journal papers are more accessible. All in all, New Zealanders and the geomorphological community at large are in debt to Soons. Selby, and their colleagues for a significant. up-to-date contribution to regional geomorphology. and to their publishers for its attractiveness. IAN A. BROOKS York Universitv Department of Geography Downsview, Onttrrio M3J lP3 Cattudu
The Earth’s Climate: Past und Future. By M. 1. Budyko. Academic Press. New York, 1982. $39.50
In essence. this book is an extended treatise on the future climate that will result from a combination of natural and manmade factors. This speculation is intriguing and one should be interested in the opinions of key workers in climate research on this topic. This book can thus be read as an expression of such opinions by M. I. Budyko, based on his long career studying the problem. This study is reflected in a series of books. each of which builds on the previous book to extend the discussion into new areas. Climate and Life (Budyko. 1974, Academic Press, New York) collected this author’s empirical description of global climate, primarily the surface-energy budget and the associations of flora and fauna which define climate zones. Climate Changes (Budyko. 1977, American Geophysical Union, Washington, D.C.) described Budyko’s well-known energy-balance climate model, compared its behavior
BOOK REVIEWS with past climate records, and briefly discussed the future climate. This new book briefly reviews all of the previous material with only minor changes and additions (e.g., evaluation of CO2 amount in Chapter 2). and expands the discussion of man’s effects on climate and what the future climate may be like. Taken as Budyko’s opinion, with some supporting arguments and evidence, this book is of interest and should be read. However, if the reader is looking for a review and discussion of climate research on the same level as in technical papers on this subject, then this book is flawed in several respects. One problem, a chronic symptom of a fast-moving research field, is that some material discussed and reviewed is badly out-of-date. Although Budyko tends to rely on much of his older work without much alteration or change (e.g., almost no satellite observations are considered to confirm or deny the earlier results of analysis of ground-based observations), much of the problem is caused by the lengthy publishing cycle and the even lengthier translation cycle. Judging from the publication date of the Russian version of this book and assuming a similar delay for translation of English language papers into Russian, one can estimate that Budyko probably wrote this book four or five years ago using available literature that was at least two to three years old (i.e., from 1977 or 1978). A second problem is a rather uncritical approach to climate data and modeling, often reflected in a tendency to convert modeling results or qualitative analysis into “data.” The key issue for discussing the future climate is clearly understanding the climate’s sensitivity to both natural and manmade perturbations. In this book, the presentation of comparisons between models and paleoclimatic data and between different models is, at best, very confused. In his rush to confirm the correctness of his model so that it can be used to predict the future, Budyko violates two of his own three cardmal principles; namely, his model is highly tuned to current and recent climatic conditions and does not include all of the principal feedbacks. In addition, Budyko’s comparisons appear to employ a bewildering array of different sensitivities depending on which problem he discusses; that is, the apparent agreement appears to be obtained by using different models with and without various processes. Three specific problems are outlined below. (1) Water-vapor feedback. Despite a specific claim to the contrary, Budyko’s energy-balance model does not include the effect of changing water amount with changing temperature; the expression for outgoing infrared radiation is linear in (surface) temperature, with coefficients based on the current climate. A change in water abundance would change these coefficients. The fixed coefficients also do not account for lapse-rate changes or changes in horizontal water transports with changing climate. The diffusive parameterization of dynamic heat transport that is considered to get the latitudinal temperature distribution also does not in-
257
elude changes in the dynamics or its water transport. The latter subject is discussed to predict precipitation changes but the effects on temperature are not included in the model. (2) Cloud feedback. We do not know yet whether this is important for climate changes, but the neglect of this process in the model because of Cess’s seasonal analysis is equivalent to tuning the model to the current climate, something Budyko claims one should not do. Indeed, there are other analyses besides that of Cess which get different answers. Which answer is correct is not known, but the cloud cover on a completely glaciated Earth is probably different than current conditions, though not in Budyko’s model. (3) Ice-albedo feedback. Several studies show that this feedback is not nearly as strong as the author has proposed because clouds reduce the effect of ice/ snowline changes on the planetary albedo. Budyko mentions this but still uses the much larger sensitivity in some of his results. Elsewhere in the book, he seems to quote a sensitivity which can only be correct if ice-albedo feedback is neglected. The range of sensitivities used seems to be about a factor of 2. Budyko does compare his model with selected results from Manabe’s work, but this comparison is mostly specious. Not only does ice-albedo feedback come and go during this comparison, but there is no discussion of the large variation in Manabe’s models or of the fact that many processes included in one model are very different in the other. The fact that two models agree is not convincing evidence of validity as yet. The most interesting result of all this is Budyko’s opinion that it is only the sheerest luck that any life has survived on Earth at ah! His model is so sensitive in the cold direction that it glaciates the whole Earth with the slightest provocation. Another response to these facts might be suspicion that the model needs more work. In the hot direction, Budyko’s model seems to retain its sensitivity, caused primarily by the icealbedo feedback process, even at temperatures high enough to remove all snow and ice at the poles. (There also appears to be some problem in thermal time constants; ice melting might keep the sea-surface temperatures lower than radiative equilibrium for awhile.) Budyko’s analysis is challenging and thought provoking and deserves attention, but this simplified approach to a complex problem is also beginning to show its shortcomings. The simple model analysis illustrates the importance of several climate-changing processes, some for which man is responsible. But proper consideration of the complex interactions in the Earth’s complete environment is necessary for reliable climate forecasts. W. B. Rossow National
Aeronautics & Space Administration Goddard Space Flight Center Institute for Space Studies New York, New York 10025
BOOK REVIEWS
tice to the large Central Volcanic Region with lucid treatments of ignimbrite sheets and central eruptive structures which vary in form with petrology. Neal1 on Taranaki gives useful detail on large and.small volcanic landforms on and around Mt. Egmont in one halfchapter. The other half discusses Taranaki’s inland hilly terrain and its coastal Quaternary marine terraces, and would better have been part of Heerdegen’s following chapter on neighboring Manawatu. In itself, Heerdegen’s chapter is a highly informative. well-organized discussion of the Tertiary upland denudation surface, Quaternary uplifted marine terraces, terraced alluvial tills, and multiple sheets of near-coastal dunes. Kamp on Hawke’s Bay. Kamp and Vucetich on the Wairarapa, and Eyles on Wellington excellently cover eastern and southeastern North Island. making optimal use of plate-tectonic context. In these areas, northwesterly oblique subduction of the Pacific Plate has produced northeast-trending geomorphic zones founded on back-thrust sheets. laced with dextral transcurrent faults, in a former forearc basin. Across Cook Strait. Nelson and Marlborough provinces in northern South Island lie partly within a direct extension of this tectonic environment, so that Campbell and Johnston’s emphasis here is similarly on tectonic landforms. Their map of the region may be the first dot-map to show elevation without boundaries between elevation classes, and it fails totally in its purpose. A full rather than half-page map of this region could have usefully classified tectonic landforms and showed the extent of the Tertiary denudation surface. Soons reviews Westland, between the crest of the Southern Alps and the Tasman Sea coast of South Island, emphasizing tectonic features (particularly the Alpine Fault trace) and glaciation. Little departure is made from traditional concerns and approaches. This may reflect the dual audience. but glaciated, tectonically active alpine zones in general have not easily lent themselves to dynamic geomorphic synthesis. The large size of this area also makes its geomorphic features difficult to present on page-length maps (I :2,000,000 scale). Bell’s long chapter on the geomorphic evolution of the Kawarau Valley. Otago, is anomalous as a case study in this book. Informative though it is. it takes up a disproportionate 25 pages, some of which could have done more justice to wider Otago. The geomorphic integrity of this province, with its tor-dotted Tertiary land surface and its gradient from glacial to periglacial Pleistocene morphodynamics, deserves a broader treatment on a par with other regions. Its absence from the book is a surprise, considering the amount of previous work. some very recent. Fitzharris ef crl. lump together South Island’s diverse basins and lowlands as areas where depositional surfaces predominate. Individual authors treat Canterbury Plains (Soons), Mackenzie Basin (Mansergh). and Southland Lowland (Fitzharris) as examples of responses to post-erogenic sedimentation in contrasting tectoniciphysiographic settings, modulated by
glacial/nonglacial morphogenetic cycles. Major late Quaternary deposits and surfaces deserve a correlation chart which would have better held this chapter together. In detail, I quibble with their nonconsideration of stream piracy as a major influence on the location of gorges linking tectonic basins. particularly when evidence for superposition and antecedence is not discussed. A final chapter by McKellar rather too sketchily summarizes Fiordland’s geomorphology. This is more of an interpretation of scenery for laymen. An opportunity is missed to contrast glacial style with that of the Southern Alps. and little is offered on the features for which the region is named. “Landforms of New Zealand” is handsomely produced in 18 x 24-cm format, on robust stock, with clear type and amazingly few typographical and layout errors. Illustrations are profuse: fully 20% of the book is occupied by photographs, the majority near halfpage size. Those produced from color transparencies are distinguished by slight fuzziness only because the original black-and-white ones are so crisp. Annotation with arrows and other symbols would have enhanced their utility. Stereo pairs are conspicuous by their absence. References follow each chapter and are current to 1981 in (only) three chapters. Many are relatively inaccessible to overseas readers and some are given as theses, where the derived journal papers are more accessible. All in all, New Zealanders and the geomorphological community at large are in debt to Soons. Selby, and their colleagues for a significant. up-to-date contribution to regional geomorphology. and to their publishers for its attractiveness. IAN A. BROOKS York Universitv Department of Geography Downsview, Onttrrio M3J lP3 Cattudu
The Earth’s Climate: Past und Future. By M. 1. Budyko. Academic Press. New York, 1982. $39.50
In essence. this book is an extended treatise on the future climate that will result from a combination of natural and manmade factors. This speculation is intriguing and one should be interested in the opinions of key workers in climate research on this topic. This book can thus be read as an expression of such opinions by M. I. Budyko, based on his long career studying the problem. This study is reflected in a series of books. each of which builds on the previous book to extend the discussion into new areas. Climate and Life (Budyko. 1974, Academic Press, New York) collected this author’s empirical description of global climate, primarily the surface-energy budget and the associations of flora and fauna which define climate zones. Climate Changes (Budyko. 1977, American Geophysical Union, Washington, D.C.) described Budyko’s well-known energy-balance climate model, compared its behavior
BOOK REVIEWS with past climate records, and briefly discussed the future climate. This new book briefly reviews all of the previous material with only minor changes and additions (e.g., evaluation of CO2 amount in Chapter 2). and expands the discussion of man’s effects on climate and what the future climate may be like. Taken as Budyko’s opinion, with some supporting arguments and evidence, this book is of interest and should be read. However, if the reader is looking for a review and discussion of climate research on the same level as in technical papers on this subject, then this book is flawed in several respects. One problem, a chronic symptom of a fast-moving research field, is that some material discussed and reviewed is badly out-of-date. Although Budyko tends to rely on much of his older work without much alteration or change (e.g., almost no satellite observations are considered to confirm or deny the earlier results of analysis of ground-based observations), much of the problem is caused by the lengthy publishing cycle and the even lengthier translation cycle. Judging from the publication date of the Russian version of this book and assuming a similar delay for translation of English language papers into Russian, one can estimate that Budyko probably wrote this book four or five years ago using available literature that was at least two to three years old (i.e., from 1977 or 1978). A second problem is a rather uncritical approach to climate data and modeling, often reflected in a tendency to convert modeling results or qualitative analysis into “data.” The key issue for discussing the future climate is clearly understanding the climate’s sensitivity to both natural and manmade perturbations. In this book, the presentation of comparisons between models and paleoclimatic data and between different models is, at best, very confused. In his rush to confirm the correctness of his model so that it can be used to predict the future, Budyko violates two of his own three cardmal principles; namely, his model is highly tuned to current and recent climatic conditions and does not include all of the principal feedbacks. In addition, Budyko’s comparisons appear to employ a bewildering array of different sensitivities depending on which problem he discusses; that is, the apparent agreement appears to be obtained by using different models with and without various processes. Three specific problems are outlined below. (1) Water-vapor feedback. Despite a specific claim to the contrary, Budyko’s energy-balance model does not include the effect of changing water amount with changing temperature; the expression for outgoing infrared radiation is linear in (surface) temperature, with coefficients based on the current climate. A change in water abundance would change these coefficients. The fixed coefficients also do not account for lapse-rate changes or changes in horizontal water transports with changing climate. The diffusive parameterization of dynamic heat transport that is considered to get the latitudinal temperature distribution also does not in-
257
elude changes in the dynamics or its water transport. The latter subject is discussed to predict precipitation changes but the effects on temperature are not included in the model. (2) Cloud feedback. We do not know yet whether this is important for climate changes, but the neglect of this process in the model because of Cess’s seasonal analysis is equivalent to tuning the model to the current climate, something Budyko claims one should not do. Indeed, there are other analyses besides that of Cess which get different answers. Which answer is correct is not known, but the cloud cover on a completely glaciated Earth is probably different than current conditions, though not in Budyko’s model. (3) Ice-albedo feedback. Several studies show that this feedback is not nearly as strong as the author has proposed because clouds reduce the effect of ice/ snowline changes on the planetary albedo. Budyko mentions this but still uses the much larger sensitivity in some of his results. Elsewhere in the book, he seems to quote a sensitivity which can only be correct if ice-albedo feedback is neglected. The range of sensitivities used seems to be about a factor of 2. Budyko does compare his model with selected results from Manabe’s work, but this comparison is mostly specious. Not only does ice-albedo feedback come and go during this comparison, but there is no discussion of the large variation in Manabe’s models or of the fact that many processes included in one model are very different in the other. The fact that two models agree is not convincing evidence of validity as yet. The most interesting result of all this is Budyko’s opinion that it is only the sheerest luck that any life has survived on Earth at ah! His model is so sensitive in the cold direction that it glaciates the whole Earth with the slightest provocation. Another response to these facts might be suspicion that the model needs more work. In the hot direction, Budyko’s model seems to retain its sensitivity, caused primarily by the icealbedo feedback process, even at temperatures high enough to remove all snow and ice at the poles. (There also appears to be some problem in thermal time constants; ice melting might keep the sea-surface temperatures lower than radiative equilibrium for awhile.) Budyko’s analysis is challenging and thought provoking and deserves attention, but this simplified approach to a complex problem is also beginning to show its shortcomings. The simple model analysis illustrates the importance of several climate-changing processes, some for which man is responsible. But proper consideration of the complex interactions in the Earth’s complete environment is necessary for reliable climate forecasts. W. B. Rossow National
Aeronautics & Space Administration Goddard Space Flight Center Institute for Space Studies New York, New York 10025