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Geology and the environment—keynote to EUG V Symposium 11
Engineering Geology,29 (1990) 273-277 Elsevier SciencePublishers B.V., Amsterdam
273
Geology and the environment keynote to EUG V Symposium 11 Eugen Seibold President European Science Foundation, Geologisches Institut der Universitiit, Albertstr. 23b, 78 Freiburg (F.R. Germany)
ABSTRACT Seibold, E., 1990. Geology and the environment--keynoteto EUG V Symposium 11. Eng. Geol., 29: 273-277.
Geologists are increasingly involved in environmental problems firstly because man has become a geological factor. It began with neolithic agriculture and deforestation influencing soil erosion, ground water and possibly local climates in nontropical regions. More than 2300 years ago Plato complained environmental destruction in his dialogue "Kritias": "In former times, when forests covered the mountains of Attica, plenty of soil absorbed and stored water. Therefore it was distributed gradually from above and could feed springs. But now the fertile and soft soil has been eroded and only the meagre skeleton of the landscape has been left over--similar to a skeleton of a body weakened by illness." But at present even global climatic consequences are discussed as possible consequences of widespread tropical deforestation. Since about a century industrialisation begins to multiply some of these factors, especially by gaseous, fluid or solid waste products. At present in industrialized areas each man moves about 20 t of geological materials per year. If at the end of our century this is done by 1000 million people, this will become some 20 bill. tons altogether per year, and that is about the volume of oceanic crust produced yearly at the midoceanic ridges. Like the history of all other celestial bodies, the history of our Earth is not cyclic but has a direction. However, the organic evolution on our planet implies an additional arrow of time. Plant photosynthesis changed in Precambrian times the composition of the atmosphere, giving way to the evolution of animals. Vegetation conquered the continents in Palaeozoic times as calcareous microorganisms conquered the oceans in Mesozoic times, both influencing deeply the geochemical cycles. In much shorter time spans man was able to enter in these global change scenarios. Secondly, geologists are increasingly involved in environmental problems because higher demands and growing population density need advise from geologists to get energy, mineral resources, including water, food or development areas. A Special factor is the trend to agglomerate people and industries in urban areas. Urban 0013-7952/90/$03.50
© 1990-- Elsevier SciencePublishers B.V.
274
E SEIBOLD
population has increased ten times since 1920 (from 100 to 1000 million) while the rural population only has increased to roughly twice the size. By the turn of the century ahnost one half of humanity is expected to live in urban centres. Hong Kong covers an area of about 1050 km 2 with more than 5.4 million inhabitants. Therefore there is a concentration of 4770 people/kin 2 and in places even more than 100,000 people km 2. Most environmental problems are problems of concentration, beginning with this general overpopulation and urban agglomerations and ending with toxic substances in soil and water or with CO2 in the atmosphere. RESTRICTIONS
AND DIFFICULTIES
Of course only some aspects of our environment and its changes can be treated professionally by a geologist because his environmental expertise is restricted to the soil and its geological substratum. It is restricted to the skin of our earth: as a basis for agricultural and forestry production; as a reservoir and filter for our water supply; as a source of minerals including fossil fuels; as a building site for residential and industrial purpose< and as a landscape which shelters man, animals and plants and a basis for our emotional well-being. And even with this restriction the geoscientist is confronted with at least four general difficulties: complexity, global and regional aspects, the problem of scales, and natural or man-made changes. However, since being a student, he is trained to include physical, chemical and biological aspects in our considerations. From fieldwork, mapping and his many international relations he gets the experience that local, regional and global conditions are intimately interrelated but also that global processes can affect local conditions in very different ways. One degree centigrade more in average annual temperature or 100 m m more annual precipitation may not cause too much change in tropical areas but may have severe consequences for some temperate areas or for the Sahel zone. Many of us worked and lived in such areas trying to help developing countries threatened by such natural or man-made changes. Europe has even a historical responsibility to do so and additionally we are living more or less in luxury and "We can allow ourselves to make mistakes and the poorer parts of the world cannot" (Sir Herman Bondi commenting the Brundtland Report). Geologists know about the importance of scales in space and in time. For agriculture and forestry we have to look several metres down, that means to "soil" in a narrow sense, for open pit mining and other technical measures normally at several tens of metres, for groundwater, mining, tunnelling or underground storing at some hundreds of metres, and finally at some thousands of metres for oil, gas or geothermal energy exploitation. Changes are problems especially concerning time. Earth history is a sequence of changes, mostly gradual, sometimes sudden and often catastrophic as volcanic eruptions or earthquakes. But in general the gradual changes are only of academic interest. Normally people are concerned with possible changes that may occur over some decades, say half a century, related to the fate of our grand children. Indeed, much environmental damage can be restored within similar periods: over-fertilized soils in about 5 years, water quality in rivers in about 10 to 20 years,
GEOLOGY AND THE ENVIRONMENT
275
reforestation with pines in 10 years, with Douglas Firs in higher latitudes in 120 years. But to regain groundwater quality may last even longer. Geologically all these changes are gradual. But for man some of these changes may have dramatic consequences if they occur too rapidly. Hopefully, the scenario of global warming related to man's different present activities will give us time enough to adapt ourselves to possible consequences or to mitigate negative ones. Part of these problems were discussed in a Report from the World Commission of Environment and Development "Our Common Future". This Brundtland Report, named after the Norwegian Prime Minister, was published in April 1987. It stresses on areas of population, food supply, loss of species, energy, industry and human settlement, but only some 5 of the 23 members of the commission were natural scientists by training, none of them were geologists. As optimists we may stress with satisfaction that finally powerful politicians became aware of these problems. As geologists, however, we have to try harder to get more visibility and to prove to society that we are able and willing to help by research and advice. WHAT SHOULDWE DO? Firstly, we have to continue to do "offensive" research, exploring for energy and mineral resources, including groundwater, and defining geologically optimal areas for settlement, recreation or the extraction of bulk materials, disposal of waste products. More and more, however, we are asked also to do defensive research relevant to the restoration of open pit mines, to the avoidance of subsidence and of pollution by heavy metals or anthropogenic organic compounds. Of course these terms are a bit artificial because "defensive" research in recycling may help us to exploit old tailings or to reuse polluted water repeatedly. "Offensive" gentechnology may help to reduce energy consumption by microbial treatment of ores. Secondly, we have to look continuously after basic principles and laws behind our complex environmental situations. Even environmental geologists or engineers deeply involved in hasty daily work should try to get a better understanding--statically of materials and structures, dynamically of processes. What a challenge it is for example to deal with soils! Soil is a renewable mineral resource but it takes many generations to renew it from bare rocks even under good climatic conditions. Therefore soil erosion by monoculture or careless deforestation is one of the biggest dangers since Plato. Another is related to the disturbance of the water budget by wrong irrigation. Yet another is due to the fact that soil is a filter, buffer and reservoir, a sink for different materials including heavy metals or anthropogenic organic compounds from chemical plants. Pollution as enrichment of substances which are not found in this form or concentration in the eco-system, is therefore a special soil problem, because the mobility of all materials of environmental concern is lower in soil as compared to water or air. Filters accumulate. A country-wide geochemical survey may begin to study river sediments as indicators for a whole river basin. Today geochemical atlases complement geological maps. But even in a heavily industrialized region as the Neckar basin, the river clay fraction contains normal crustal abundances for many
276
I SEIBOLD
metals. Indeed weathering is the origin of natural pollution of rain water. Without it we would not have a salty sea. The investigation of natural cycles, transport mechanisms and velocities, mass balances, mobilisation or immobilisation, especially by variations of pH, humic substances, iron, clay minerals, together with microbial interactions, is therefore a fundamental task. And in general many more quantitative approaches are needed. This brings me to my third point. Engineering geology needs a fundamental understanding of the way in which natural rocks, sediments and soils can be loaded or cut away without detriment. But additionally engineers need quantitative parameters to insert them into formulas, and normally they are not very happy about the complications geologists may contribute: seasonal changes, weathering, slope qualities, tectonic features as faults, folds, cleavage. But the forecast of possible damage and its prevention is a contribution to a better environment, too. Finally, being scientists we shall never forget that we can only offer alternatives for political decisions concerning environments. Of course as citizens we may have priorities and we should look after them, A good example to offer alternatives are the maps for environmental planning. Through maps a geologist gets a three-dimensional picture of a landscape, and even a four-dimensional view if one includes Earth h i s t o r y - - a n d if one is a good geologist. A good chemist has the same stimulus to the imagination looking at a chemical formula. The task for geologists, however, is to simplify these applied maps so that their messages reach engineers, planners, politicians, in a way that the messages will be understood. These maps offer different possibilities or even recommendations to use an area primarily to extract natural resources or to use it for settlements or traffic routes or for waste disposal sites or for the preservation for recreation or as natural parks. They may contain information to mitigate damages, for instance by landslides, or at building sites possibly exposed to earthquakes. Again there are m a n y chances and needs to assist developing countries in preparing maps for planning purposes, especially in fast growing urban areas. The role of geology, as for science in general, is to define the pros and contras of different alternatives. Politicians then may set priorities and must finally decide. Often they have to do it with an incomplete scientific analysis of all factors or alternatives and we have to accept this situation for politicians. On the other hand we have to tell them honestly what we know and where we have gaps in our knowledge. In my mind the most difficult situation for science in society at present are our ambiguous findings and uncertain forecasts of our climatical future during the next centuries. But nevertheless I would like to end with some remarks about handling problems of forecasting natural hazards in our social framework. Firstly, again we must improve our understanding of principles and processes. This means again: more basic science! How and how strongly are stresses accumulating in the earth's crust? What are the messages from the mantle m a g m a s and how are they coming to the surface and why are there less dangerous explosions with ash falls or on the other hand the usually catastrophic pyroclastic flows? What are the critical parameters for slope stability and how can they be quantified? And in general: are there any cyclical factors involved'? Secondly, we have to improve our ability to predict these natural hazards. There is
GEOLOGY AND THE ENVIRONMENT
277
a curious antagonism in earth sciences. With the theory of plate tectonics we can define the most dangerous regions for earthquakes or volcanic eruptions globally. They occur essentially at plate boundaries, less--and not so easily understood--in interplate areas. But to predict an earthquake or an eruption exactly, that is where and when and with what magnitude, still remains one of our greatest challenges. In such a situation our special duty is thirdly to prevent or mitigate damages caused by natural hazards: more and more special maps with risk zones are available for planning of settlements and industries or for strengthening structures on land, at coasts or offshore. Best known are seismic risk zones, based roughly on tectonic features and in detail additionally on stability and other qualities of the foundation soil. Altogether the geologist may add his experience when earthquake codes have to be formulated for engineers and architects, especially for sensitive big structures such as nuclear power plants, dams, high towers and chimneys, bridges, pipelines. One of the easier ways to avoid damage is of course a very simple one: use at least good quality concrete! Returning to the theme of this section about natural hazards as a task for geology, there is in general only one possible approach---defensive planning, a passive approach. Nature commands earthquakes and we have to react. But we can obey its laws in planning suitable man-made structures and in trying to avoid high risk areas in spite of a growing population. In 1965 Edward Nicholson, a former Director General of the Nature Conservancy in London, wrote in a contribution to a book "The World in 1984": "After long neglect and maltreatment the environment which shelters, supports and inspires us is coming to be looked at with new interest and respect." Our symposium "Geology and Environment" demonstrates the truth of this forecast. To come back to my introduction, geology came nearer to man because he becomes more and more a geological factor. But we geologists got the task to answer increasingly to questions from and for mankind. What a bundle of human and scientific challenges! ACKNOWLEDGEMENTS The author wishes to acknowledge the assistance of many earth scientists engaged in Environmental Geology who could not be mentioned in this keynote lecture. However I could (1) use part of my Annual Lecture, Natural Environment Research Council, London April 6, 1988 "Planning for a better Environment: The Role of Geology". (2) Many details are published in: Bender, F. (Editor), Angewandte Geowissenschaften, Vol. 3, Chapter 4.3, Geowissenschaften und Umweltschutz, pp. 567-637, Enke, Stuttgart, 1984. Bender, F. (Editor), Geo-Resources and Environment. Proc. 4th Int. Symp. Hannover, 16-18 October 1985, 149 pp., Schweizerbart, Stuttgart, 1986. Wolff, F.C. (Editor), Geology for Environmental Planning. Proc. Int. Symp. Geological Mapping in the Service of Environmental Planning, Trondheim, 6-9 May 1986, 121 pp., Norges Geologiske Undersokelse, Trondheim, Spec. Publ. 2, 1987.
273
Geology and the environment keynote to EUG V Symposium 11 Eugen Seibold President European Science Foundation, Geologisches Institut der Universitiit, Albertstr. 23b, 78 Freiburg (F.R. Germany)
ABSTRACT Seibold, E., 1990. Geology and the environment--keynoteto EUG V Symposium 11. Eng. Geol., 29: 273-277.
Geologists are increasingly involved in environmental problems firstly because man has become a geological factor. It began with neolithic agriculture and deforestation influencing soil erosion, ground water and possibly local climates in nontropical regions. More than 2300 years ago Plato complained environmental destruction in his dialogue "Kritias": "In former times, when forests covered the mountains of Attica, plenty of soil absorbed and stored water. Therefore it was distributed gradually from above and could feed springs. But now the fertile and soft soil has been eroded and only the meagre skeleton of the landscape has been left over--similar to a skeleton of a body weakened by illness." But at present even global climatic consequences are discussed as possible consequences of widespread tropical deforestation. Since about a century industrialisation begins to multiply some of these factors, especially by gaseous, fluid or solid waste products. At present in industrialized areas each man moves about 20 t of geological materials per year. If at the end of our century this is done by 1000 million people, this will become some 20 bill. tons altogether per year, and that is about the volume of oceanic crust produced yearly at the midoceanic ridges. Like the history of all other celestial bodies, the history of our Earth is not cyclic but has a direction. However, the organic evolution on our planet implies an additional arrow of time. Plant photosynthesis changed in Precambrian times the composition of the atmosphere, giving way to the evolution of animals. Vegetation conquered the continents in Palaeozoic times as calcareous microorganisms conquered the oceans in Mesozoic times, both influencing deeply the geochemical cycles. In much shorter time spans man was able to enter in these global change scenarios. Secondly, geologists are increasingly involved in environmental problems because higher demands and growing population density need advise from geologists to get energy, mineral resources, including water, food or development areas. A Special factor is the trend to agglomerate people and industries in urban areas. Urban 0013-7952/90/$03.50
© 1990-- Elsevier SciencePublishers B.V.
274
E SEIBOLD
population has increased ten times since 1920 (from 100 to 1000 million) while the rural population only has increased to roughly twice the size. By the turn of the century ahnost one half of humanity is expected to live in urban centres. Hong Kong covers an area of about 1050 km 2 with more than 5.4 million inhabitants. Therefore there is a concentration of 4770 people/kin 2 and in places even more than 100,000 people km 2. Most environmental problems are problems of concentration, beginning with this general overpopulation and urban agglomerations and ending with toxic substances in soil and water or with CO2 in the atmosphere. RESTRICTIONS
AND DIFFICULTIES
Of course only some aspects of our environment and its changes can be treated professionally by a geologist because his environmental expertise is restricted to the soil and its geological substratum. It is restricted to the skin of our earth: as a basis for agricultural and forestry production; as a reservoir and filter for our water supply; as a source of minerals including fossil fuels; as a building site for residential and industrial purpose< and as a landscape which shelters man, animals and plants and a basis for our emotional well-being. And even with this restriction the geoscientist is confronted with at least four general difficulties: complexity, global and regional aspects, the problem of scales, and natural or man-made changes. However, since being a student, he is trained to include physical, chemical and biological aspects in our considerations. From fieldwork, mapping and his many international relations he gets the experience that local, regional and global conditions are intimately interrelated but also that global processes can affect local conditions in very different ways. One degree centigrade more in average annual temperature or 100 m m more annual precipitation may not cause too much change in tropical areas but may have severe consequences for some temperate areas or for the Sahel zone. Many of us worked and lived in such areas trying to help developing countries threatened by such natural or man-made changes. Europe has even a historical responsibility to do so and additionally we are living more or less in luxury and "We can allow ourselves to make mistakes and the poorer parts of the world cannot" (Sir Herman Bondi commenting the Brundtland Report). Geologists know about the importance of scales in space and in time. For agriculture and forestry we have to look several metres down, that means to "soil" in a narrow sense, for open pit mining and other technical measures normally at several tens of metres, for groundwater, mining, tunnelling or underground storing at some hundreds of metres, and finally at some thousands of metres for oil, gas or geothermal energy exploitation. Changes are problems especially concerning time. Earth history is a sequence of changes, mostly gradual, sometimes sudden and often catastrophic as volcanic eruptions or earthquakes. But in general the gradual changes are only of academic interest. Normally people are concerned with possible changes that may occur over some decades, say half a century, related to the fate of our grand children. Indeed, much environmental damage can be restored within similar periods: over-fertilized soils in about 5 years, water quality in rivers in about 10 to 20 years,
GEOLOGY AND THE ENVIRONMENT
275
reforestation with pines in 10 years, with Douglas Firs in higher latitudes in 120 years. But to regain groundwater quality may last even longer. Geologically all these changes are gradual. But for man some of these changes may have dramatic consequences if they occur too rapidly. Hopefully, the scenario of global warming related to man's different present activities will give us time enough to adapt ourselves to possible consequences or to mitigate negative ones. Part of these problems were discussed in a Report from the World Commission of Environment and Development "Our Common Future". This Brundtland Report, named after the Norwegian Prime Minister, was published in April 1987. It stresses on areas of population, food supply, loss of species, energy, industry and human settlement, but only some 5 of the 23 members of the commission were natural scientists by training, none of them were geologists. As optimists we may stress with satisfaction that finally powerful politicians became aware of these problems. As geologists, however, we have to try harder to get more visibility and to prove to society that we are able and willing to help by research and advice. WHAT SHOULDWE DO? Firstly, we have to continue to do "offensive" research, exploring for energy and mineral resources, including groundwater, and defining geologically optimal areas for settlement, recreation or the extraction of bulk materials, disposal of waste products. More and more, however, we are asked also to do defensive research relevant to the restoration of open pit mines, to the avoidance of subsidence and of pollution by heavy metals or anthropogenic organic compounds. Of course these terms are a bit artificial because "defensive" research in recycling may help us to exploit old tailings or to reuse polluted water repeatedly. "Offensive" gentechnology may help to reduce energy consumption by microbial treatment of ores. Secondly, we have to look continuously after basic principles and laws behind our complex environmental situations. Even environmental geologists or engineers deeply involved in hasty daily work should try to get a better understanding--statically of materials and structures, dynamically of processes. What a challenge it is for example to deal with soils! Soil is a renewable mineral resource but it takes many generations to renew it from bare rocks even under good climatic conditions. Therefore soil erosion by monoculture or careless deforestation is one of the biggest dangers since Plato. Another is related to the disturbance of the water budget by wrong irrigation. Yet another is due to the fact that soil is a filter, buffer and reservoir, a sink for different materials including heavy metals or anthropogenic organic compounds from chemical plants. Pollution as enrichment of substances which are not found in this form or concentration in the eco-system, is therefore a special soil problem, because the mobility of all materials of environmental concern is lower in soil as compared to water or air. Filters accumulate. A country-wide geochemical survey may begin to study river sediments as indicators for a whole river basin. Today geochemical atlases complement geological maps. But even in a heavily industrialized region as the Neckar basin, the river clay fraction contains normal crustal abundances for many
276
I SEIBOLD
metals. Indeed weathering is the origin of natural pollution of rain water. Without it we would not have a salty sea. The investigation of natural cycles, transport mechanisms and velocities, mass balances, mobilisation or immobilisation, especially by variations of pH, humic substances, iron, clay minerals, together with microbial interactions, is therefore a fundamental task. And in general many more quantitative approaches are needed. This brings me to my third point. Engineering geology needs a fundamental understanding of the way in which natural rocks, sediments and soils can be loaded or cut away without detriment. But additionally engineers need quantitative parameters to insert them into formulas, and normally they are not very happy about the complications geologists may contribute: seasonal changes, weathering, slope qualities, tectonic features as faults, folds, cleavage. But the forecast of possible damage and its prevention is a contribution to a better environment, too. Finally, being scientists we shall never forget that we can only offer alternatives for political decisions concerning environments. Of course as citizens we may have priorities and we should look after them, A good example to offer alternatives are the maps for environmental planning. Through maps a geologist gets a three-dimensional picture of a landscape, and even a four-dimensional view if one includes Earth h i s t o r y - - a n d if one is a good geologist. A good chemist has the same stimulus to the imagination looking at a chemical formula. The task for geologists, however, is to simplify these applied maps so that their messages reach engineers, planners, politicians, in a way that the messages will be understood. These maps offer different possibilities or even recommendations to use an area primarily to extract natural resources or to use it for settlements or traffic routes or for waste disposal sites or for the preservation for recreation or as natural parks. They may contain information to mitigate damages, for instance by landslides, or at building sites possibly exposed to earthquakes. Again there are m a n y chances and needs to assist developing countries in preparing maps for planning purposes, especially in fast growing urban areas. The role of geology, as for science in general, is to define the pros and contras of different alternatives. Politicians then may set priorities and must finally decide. Often they have to do it with an incomplete scientific analysis of all factors or alternatives and we have to accept this situation for politicians. On the other hand we have to tell them honestly what we know and where we have gaps in our knowledge. In my mind the most difficult situation for science in society at present are our ambiguous findings and uncertain forecasts of our climatical future during the next centuries. But nevertheless I would like to end with some remarks about handling problems of forecasting natural hazards in our social framework. Firstly, again we must improve our understanding of principles and processes. This means again: more basic science! How and how strongly are stresses accumulating in the earth's crust? What are the messages from the mantle m a g m a s and how are they coming to the surface and why are there less dangerous explosions with ash falls or on the other hand the usually catastrophic pyroclastic flows? What are the critical parameters for slope stability and how can they be quantified? And in general: are there any cyclical factors involved'? Secondly, we have to improve our ability to predict these natural hazards. There is
GEOLOGY AND THE ENVIRONMENT
277
a curious antagonism in earth sciences. With the theory of plate tectonics we can define the most dangerous regions for earthquakes or volcanic eruptions globally. They occur essentially at plate boundaries, less--and not so easily understood--in interplate areas. But to predict an earthquake or an eruption exactly, that is where and when and with what magnitude, still remains one of our greatest challenges. In such a situation our special duty is thirdly to prevent or mitigate damages caused by natural hazards: more and more special maps with risk zones are available for planning of settlements and industries or for strengthening structures on land, at coasts or offshore. Best known are seismic risk zones, based roughly on tectonic features and in detail additionally on stability and other qualities of the foundation soil. Altogether the geologist may add his experience when earthquake codes have to be formulated for engineers and architects, especially for sensitive big structures such as nuclear power plants, dams, high towers and chimneys, bridges, pipelines. One of the easier ways to avoid damage is of course a very simple one: use at least good quality concrete! Returning to the theme of this section about natural hazards as a task for geology, there is in general only one possible approach---defensive planning, a passive approach. Nature commands earthquakes and we have to react. But we can obey its laws in planning suitable man-made structures and in trying to avoid high risk areas in spite of a growing population. In 1965 Edward Nicholson, a former Director General of the Nature Conservancy in London, wrote in a contribution to a book "The World in 1984": "After long neglect and maltreatment the environment which shelters, supports and inspires us is coming to be looked at with new interest and respect." Our symposium "Geology and Environment" demonstrates the truth of this forecast. To come back to my introduction, geology came nearer to man because he becomes more and more a geological factor. But we geologists got the task to answer increasingly to questions from and for mankind. What a bundle of human and scientific challenges! ACKNOWLEDGEMENTS The author wishes to acknowledge the assistance of many earth scientists engaged in Environmental Geology who could not be mentioned in this keynote lecture. However I could (1) use part of my Annual Lecture, Natural Environment Research Council, London April 6, 1988 "Planning for a better Environment: The Role of Geology". (2) Many details are published in: Bender, F. (Editor), Angewandte Geowissenschaften, Vol. 3, Chapter 4.3, Geowissenschaften und Umweltschutz, pp. 567-637, Enke, Stuttgart, 1984. Bender, F. (Editor), Geo-Resources and Environment. Proc. 4th Int. Symp. Hannover, 16-18 October 1985, 149 pp., Schweizerbart, Stuttgart, 1986. Wolff, F.C. (Editor), Geology for Environmental Planning. Proc. Int. Symp. Geological Mapping in the Service of Environmental Planning, Trondheim, 6-9 May 1986, 121 pp., Norges Geologiske Undersokelse, Trondheim, Spec. Publ. 2, 1987.