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Part I: Restructuring resource use
2. The biophysical basis of
eco-restructuring: An overview of current relations between human
economic activities and the global system
3. Ecological process engineering: The
potential of bio-processing
4. Materials futures: Pollution prevention,
recycling, and improved functionality
5. Global energy futures: The long-term
perspective for eco-restructuring
6. Fuel decarbonization for fuel cell
applications and sequestration of the separated CO2
7. Photovoltaics
Introduction
The
earth system
The climate system and climatic change
Climatic change and vulnerability
Biological
diversity
Fresh
water
Soils
The
solid earth (lithosphere)
Land-cover
and land-use changes
Human impacts and industrial metabolism
The
case of West Africa
Outlook
Walther Manshard
Eco-restructuring cuts across almost all scientific subjects and covers nearly all chapters of Agenda 21. But, for the purposes of this chapter, two focal points in the global debate are emphasized: namely the UNCED conventions on climatic change and biological diversity. Broad interdisciplinary research themes, such as industrial metabolism, industrial ecology, landscape analysis, and "eco-restructuring," are now emerging. It is to be hoped that they will contribute to better understanding of the interactions between human activities and the biosphere. It is helpful to look at the environment as an exhaustible resource and at the earth as a self-organizing system. This overview attempts to point out some useful principles for steering the processes of "eco-transition." It is based on lessons taken from cases - including climatic change, biodiversity, and African development to highlight problems and approaches.
In this context it is useful to focus attention on a few of the more fragile subsystems such as fresh water, soils, and aspects of relief and surface development. These biophysical elements belong both to the natural environment and to the economic system. Human driving forces, especially industrial development, have an impact on environment, especially on natural resource depletion and land-use and land-cover transformation. Similarly, climatic and biogeochemical systems have an influence on the pace and scope of eco-restructuring.
The chapter concludes with a regional thumbnail sketch on a sub continental scale, focusing on one of the world's least developed regions (West Africa). Because of the lack of hard empirical data, this discussion must largely remain on a descriptive level, primarily by making use of geographical information. It stresses the problems of sustainability and vulnerability of the African continent. There is still a lot of research to be done to find out how Africa contributes to the global situation.
The total earth system consists of the geosphere and the biosphere. The geosphere is conventionally defined as the lithosphere (rocks), the hydrosphere (oceans, rivers, and lakes), and the atmosphere, together with the pedosphere (soils) and the cryosphere (ice). It constitutes the substrate for the biosphere, which is the earth's integrated life support system.
On the other hand, the biosphere can also be subdivided into terrestrial and marine subsystems, with living organisms further subdivided into animal and vegetable species (plus bacteria). The animal world consists of humans, other mammals, birds, fish, insects, and a number of other orders, phyla, and families. The human section (which dominates the rest) is sometimes called the anthroposystem (Husar 1993). This can be further broken down into the sociosphere and the "technosphere." The latter, in particular, influences the other different natural systems of the geosphere, and is in turn influenced by them.
The human impact on the other components of the earth system has now reached a level comparable to - and in some respects greater than - that of natural processes. Anthropogenic activities include the extraction of raw materials, their physical and chemical separation and refining, as well as their conversion and distribution. Manufacturing represents only a small fraction of these activities. Indeed, from some environmental standpoints it is not necessarily the most important. Extractive industries, including agriculture and forestry, and also "final" consumption (including personal transportation) often generate more harmful waste materials and residues than cutting, or shaping, or forming, or assembly. In spite of the adoption of waste-minimization policies, the continued use of new "virgin" materials and fossil fuels still imposes a heavy burden on the biophysical environment. This can be overcome only in time by more appropriate research and development strategies, including information systems that facilitate the optimization of the exchanges between industry and nature (Ayres et al. 1992). An interesting and different approach is offered by the concept of "landscape ecology." This has developed out of a kind of merger between traditional geography and ecology. A "landscape" is, by definition, a kind of shorthand for the complex spatial interaction patterns of natural and human systems. Widespread landscape transformations have now become a pressing global problem. There are no landscapes, except perhaps in Antarctica, free from human influence. The industrial type of landscape in particular reflects a very high level of technological and environmental interference by humans.
The climate system and climatic change
The basic objective of the Framework Convention on Climate Change (1992; further discussed by the Berlin Conference in 1995) was to further a political process leading to "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent anthropogenic interference with the climate system" (Article 2) and to do so in such a manner as to allow ecosystems to adapt naturally, and so as not to interfere with food production and economic development. Needless to say, it is also important to understand better the processes that are influenced by the earth's atmosphere on a global, regional, and local level. These include biophysical, geochemical, hydrological-oceanic, and socio-economic processes. This calls for an improved understanding of the socioeconomic consequences of climatic change and for further investigations of the response mechanisms to mitigate such changes.
The climate system is mainly driven by solar radiation. The major engine of global atmospheric circulation is the so-called hydrological cycle. Solar heating of the ocean surface causes evaporation of water. The moist air rises until it cools to condensation point. The water vapour condenses and returns to the earth, partly over land. The condensation process releases heat in the atmosphere. Water from precipitation then flows from the land back to the sea, carrying nutrient elements (and causing salinity gradients). Thermal imbalances between high and low latitudes drive both winds and ocean currents, redistributing energy and matter within the atmosphere and the hydrosphere.
As a result of the interactions between solar radiation and the geo/ biosphere, the climate system changes continually. This has occurred throughout the history of our planet. However, in the recent past a new factor has appeared: increased emission of "greenhouse gases" or GHGs (e.g. carbon dioxide, methane, nitrous oxide, chlorofluorocarbons). These emissions are strongly linked to human activities, especially the combustion of fossil fuels and high-intensity agriculture. The build-up of these gases in the atmosphere has made it act somewhat like a mirror for heat radiation. This has led to a marked global warming process, whose magnitude and rate are still under discussion.
The task of determining likely "winners" and "losers" resulting from this ongoing climatic change is extremely difficult. It will affect mainly agriculture. Among the industrialized countries, agriculture accounts for only a very small part of the economy. This has led some economists (mainly in the United States) to conclude that climate warming is not a great concern and that major efforts to counteract it would not be economically justified. Yet it is undeniable that agriculture is essential for human survival and that it counts for a much larger part of the economies of poorer developing countries. The Intergovernmental Panel on Climate Change (IPCC 1990) projects that the results of global warming, such as increased precipitation and longer frost-free periods, could bring about rather limited immediate benefits to some regions, located mainly in the northern hemisphere. In the South, however, where food supplies are regionally more limited, difficulties related to food security problems may increase. Since climate warming would also be accompanied by sealevel rise, it is of even more immediate concern to small low-lying island nations and countries such as Bangladesh with large populations heavily concentrated in estuarine zones.
One of the most significant results of climate change is likely to be the shifting of agro-climatic zones, although the spatial distribution of such shifts is still difficult to predict. Also sealevel rise affecting low-lying coastal areas by flooding will influence industrial planning and development. The establishment of international funds to counter the adverse consequences of climatic change and the creation of an International Insurance Pool (IIP) to provide insurance against the consequences of sealevel rise are under discussion.
An important implication of the IPCC's work is that uncertainty is itself costly. In other words, it is important to find out (and quantify) the real costs of action (or inaction) in the area of climatic change and to establish economic incentives or disincentives for achieving the stabilization and eventual reduction of greenhouse gas emissions. In this respect, a narrow application of the "polluter-pays" principle would adversely affect economic development in some countries (notably China and India) that are heavily committed to the use of coal. Hence, there is increasing interest in "joint implementation" and such devices as tradable permits (see chap. 12 in this volume).
Other important aspects of human activities on the global level include stratospheric ozone depletion and its potential biospheric effects, as well as the processes involved with acid deposition. Both can be directly linked to industrial emissions of gaseous pollutants. Stratospheric ozone is important for the biosphere because of its absorption of ultraviolet (UV) radiation, which is harmful to humans, animals, and plants. But long-lived chlorinated fluorocarbons (CFCs), which gradually diffuse from the lower atmosphere into the stratosphere, are broken up by UV radiation, releasing atomic chlorine (Cl) atoms. These, in turn, react with ozone (O3) molecules, which are converted back into ordinary molecular oxygen and atomic oxygen, leaving the chlorine atoms free to attack more ozone. Each chlorine atom can destroy hundreds of thousands of ozone molecules. Hence, CFCs are literally capable of destroying the ozone layer. Thanks to the Montreal Protocol (1987) and the subsequent London revision (1990), CFCs are being phased out of production, at least in the industrial world. But, because so many CFCs are already in the atmosphere, their environmental impacts are likely still increasing and will not disappear for many decades.
Acid deposition is caused by the emission of chemicals such as nitrogen oxides (NOx) and sulphur dioxide (SO2) to the atmosphere, mainly from combustion processes. Nitrogen oxides are produced in high-temperature flames when there is excess air. This happens mainly in coal-burning electric power generating plants and internal combustion engines. The nitrogen in the air itself is oxidized. Sulphur dioxides are produced when coal, containing a small percentage of sulphur, is burned or from the smelting of sulphide ores of copper, nickel, lead, or zinc. These gaseous oxides are further oxidized in the air or on the surfaces of small particles, which act as catalysts. These oxides, reacting with and dissolved in water, become nitric and sulphuric acids, respectively. They may travel hundreds of miles through the atmosphere and descend in the form of rain, fog, and snow or even in dry form. These acids are eventually deposited by rain on the surface of the earth or on the surfaces of trees and other vegetation.
This acid deposition has had great effects on aquatic ecosystems by increasing the acidity of rivers and lakes. This has negatively affected both the flora and fauna. It also has a marked direct impact on terrestrial vegetation, mainly because of its effects on soils. The acidification of forest soils releases and mobilizes metal ions (especially aluminium) that were formerly bound to clay particles. Some of these metals are toxic to trees. The ongoing discussion of the complex causes of "Waldsterben" (forest die-back) is largely related to acidification.
An interesting integrated approach to climatic impact assessment that takes into account the primary, secondary, and tertiary sectors of the economy has been proposed by Parry et al. (1988). This interaction concept not only focuses on climatic parameters but also includes social factors such as poverty, war, or hunger as necessary for a useful evaluation of the effects of climatic change. In addition to policy implications, this allows for feedback regulating and enhancing possible change effects. For instance, a change in climate may lead to a change in natural vegetation belts, which itself will influence the climate through changes in fluxes of gases or through changes in surface reflectivity. This integrated approach will allow a more comprehensive treatment of interactions between climate and society.
Climatic change and vulnerability
The concept of vulnerability is central to any research into climatic change. The World Meteorological Organization (WMO) has defined the objective of its climate programme as "determining the characteristics of human societies at different levels of development which make them either specially vulnerable or specially resilient to climatic variability and change." Vulnerability can be seen as "the degree to which a system may react adversely to the occurrence of a hazardous event" (Timmerman 1981). This concept has often been used in relation to climatic and global change research (Kates et al. 1985; Liverman 1991), being linked to terms such as resilience, marginality, susceptibility, adaptability, fragility, and criticality.
In the tropics especially, a wide-ranging integrative approach encompassing all aspects of vulnerability is needed. This includes biophysical monitoring, modeling, and studies on the transformation of the physical environment. In this respect, only an improved understanding of the socio-economic, cultural, and demographic factors will provide the necessary insight into the situation of social groups at risk. In the regional case-study on Africa, below, further reference is made to this.
The Convention on Biological Diversity (UNEP 1992) and also Chapter 15 of Agenda 21 (UNCED 1992), on the conservation of biological diversity, call for the development of national, regional, and global strategies for an improved sustainable use of biological resources. A closer integration of these strategies into the respective development plans and concepts is advocated. This would include a broader promotion of international cooperation and a furthering of the scientific and economic understanding of biodiversity in the functioning of ecological and human-use systems.
Biodiversity describes the abundant variety and variability of living organisms, which, in the context of different ecosystems, have evolved over the past 3 billion years. The biological evolution responded to unstable situations (open cycles) by "inventing" new processes to stabilize the system by closing the cycles (Ayres 1994). This self organizing capability has been called "Gala" (Margulis and Lovelock 1976; Lovelock 1987).
In the latest stage of evolution, humans, as the dominant species, have been responsible for major habitat changes. For instance, land use changes resulting in deforestation and desertification have often brought about a loss of biodiversity, both at the level of ecosystems and also within ecosystems, leading to a loss of genetic and species diversity. This loss has many wide-ranging potential and real effects on both man-made and natural ecosystems and the human populations depending on them.
In return, humans have also, over thousands of years, exploited and manipulated the genetic wealth of biodiversity by selecting and breeding crops and animals. It could perhaps be argued that the effects of climatic change upon agricultural crops would be negligible, because of their great variability. However, one of the main problems is the trend towards great genetic and ecological uniformity. This has occurred through the introduction of commercial seeds that have good yields under optimal conditions but that produce very little in less favourable environments. Therefore the conservation of indigenous varieties, bred and specialized to local conditions for centuries, is potentially advantageous (Ezcurra et al. 1991). The recent global warming trend has the consequence that these localized specialized varieties with limited distribution will disappear sooner than the more uniform commercial crops. This underlines the vulnerability of agro-ecosystems and the general importance of an increased emphasis on preserving biological and genetic diversity.
The consequences of intentional or unintentional "invasions" of living organisms, through export or exchange between different ecosystems, should also be increasingly considered. This has long been a problem associated with human commerce and colonization. Many desirable crops - including maize, potatoes, and tobacco - were brought to Europe from the Americas, for instance. Pineapples were taken to Hawaii from South America. Rubber trees were taken to Malaya and Indo-China from the Amazon valley. But pest species also migrate. The rabbit plague in Australia, Dutch Elm disease, the starling, the grey squirrel, the Norway rat, the water hyacinth, and dozens of other examples could be cited. Meanwhile, in many cases other competing species were eliminated by the interlopers.
As another response to this biological "erosion," various forms of biotechnology have emerged, ranging from traditional fermentation techniques to modern breakthroughs in genetic engineering and recombinant DNA technology (see chap. 3 in this volume). Biotechnology can offer new possibilities for food production, medicine, and energy supply, including special chemicals for improved environmental management. In addition to the protection and conservation of the biosphere, the international Convention on Biological Diversity (UNEP 1992) advocated better handling of biotechnology and improved distribution of its benefits as key elements for successful economic development.
Fresh water supply is a key factor for the maintenance of terrestrial ecosystems. A good example is the hydrology and water balance of the tropical forests, which has also become important for its impact on human land use (Douglas 1990). Estimates for the Amazon Basin suggest that a complete replacement of the rain forest by grassland (if it were possible) would increase soil and surface temperatures by 1-3°C, with rainfall and evapo-transpiration declining by 26 per cent and 30 per cent, respectively (Salati et al. 1990).
The main global water uses are for irrigation, electric power generation, and industry. Municipal uses, for washing, cooking, drinking, and sewage disposal, are comparatively minor at the global level, though locally important - especially in dry regions.
Concerning water consumption, there are important differences between the industrialized countries ("North") and the developing countries ("South"). In Europe, for instance, industrial use (including electric power) is dominant, with only 37 per cent for all other human uses, including agriculture. In Africa and Asia in the 1980s, by contrast, withdrawals for human use and agriculture were over 90 per cent of the total (Tolba and El-Kholy 1992).
In industry, much water is recycled several times before it is finally discarded as waste water. (In the United States, the petroleum refineries use water - mostly for cooling - nine times before it is discarded.) On the other hand, industrial waste water is often toxic. If it is discharged into surface water or groundwater without treatment it creates serious environmental problems. During the past 20 years (since the 1977 Mar del Plata Conference) some progress has been made in water resources management. However, recent experiences in Eastern Europe have shown that problems of water quality in the former communist countries are much more serious than it was previously thought.
It is estimated that agricultural use of water for irrigation in the South will decline further, at least in many areas such as northern China, owing to falling water tables. The share of industrial water use will rise and it is expected that an adequate supply of fresh water will constitute the most critical resource "bottleneck" at the turn of the twenty-first century.
Topsoil is a fragile and elusive interface between the biosphere and the lithosphere. The soils (i.e. the pedosphere) have been deeply affected, and even (in some cases) created, by human action. No analysis of vegetation, land cover, and land use can be undertaken without a comprehensive knowledge of the soils, their nutrient status, and their stability.
Because of the great variety and variability of soil development, in both time and space, a sharp distinction between natural and anthropogenic changes is quite difficult to make. Human-induced changes are mainly caused by agricultural land use (crops and livestock), and by transportation and settlements. Roads and settlements have decreased the total area of productive soils (especially fertile top soils) in all urbanized societies. This process is of great concern now in Asia, where most of the population still live on farms but migration to cities is accelerating.
In a number of studies of the relation of agricultural production and the population carrying capacity, the importance of soil constraints within the biophysical framework has been stressed. Several soil zones have been identified where present food demand exceeds the agricultural production potential. These are designated as critical zones of food insecurity.
Climatic and soil data have also increasingly been used to assess vulnerability. This has been done on a global scale by emphasizing biophysical driving forces. It has also been done at the local and regional scale by associating vulnerability with changes in crop yields, harvest failures, and agro-ecological potential. In this connection the ecotoxic impacts of industrial wastes and agricultural chemical usage on the biosphere have not been treated adequately.
Global change processes involving the lithosphere are often ignored. However, as the main supplier of mineral raw materials, this part of the geosphere plays a leading role in relation to important bio-geochemical and nutrient cycles. With the exceptions of carbon and oxygen, the anthropogenic mobilization of most nutrients and trace metals by industrial activities can already be compared with the natural rate. In many cases, the anthropogenic mobilization is considerably greater than the natural flux. This applies, for instance, to most heavy metals.
Processes of erosion, deposition/sedimentation, tectonic movement, and volcanic eruption can deeply affect human use-patterns, especially of the soils. Earlier assumptions about the humid tropics have increasingly been questioned. These include the assumption that weathering and chemical denudation proceeded there much faster than elsewhere and the idea that tropical rivers were only "passive conveyors" without eroding their own bed. New work on quaternary climatic changes and tectonic diversity has contributed significantly to our knowledge of the stability (and instability) of tropical landscapes (Douglas 1990).
Of course, geomorphological factors can influence technological development. An interesting example is the construction of multipurpose dams for both irrigation and power-generating purposes in the subtropical zone of excessive "planation" (or retarded valley formation). Most tropical dry savanna regions belong to this zone, which is also sometimes referred to as the savanna planation zone. These land forms are basically related to climatic factors such as sheet flow on sloping surfaces with extreme peaks of river discharge. Although it is generally perceived that big rivers cut deep gashes into the bedrock, in the semi-humid and semi-arid tropics reality is somewhat different. Here most rivers flow in shallow river beds. On tectonically stable blocks, placation surfaces are dominant even at altitudes over 1,000 m. The geomorphological term for this type of valley is "trough valley" (Young 1972) or "Flachmuldental" (Louis 1964). In these geomorphic circumstances it is quite difficult to find suitable sites for irrigation or power dams. Large technological and financial investments for this purpose can be much less profitable than in other tropical regions. It must be recognized, therefore, that the seasonally wet and dry outer tropics suffer from persisting constraints caused by land forms and river discharges which also affect the economic development of this very important climatic zone. Aside from Africa, many examples can be cited from the Deccan Plateau in India and the Planaltos on the Brazilian Shield (Weischet and Caviedes 1993).
Land-cover and land-use changes
Land-cover and land-use changes have become global in scale. For the better understanding of these changes, more work on the linkages between biophysical and human-induced driving forces is essential. Generally speaking, land cover refers to attributes of parts of the earth surface including vegetation, soil, groundwater, and topographical features. Broad categories would include, for instance, the boreal forest, tropical savanna, cropland, wetland, or settlements. On the other hand, land use refers to the purpose for which land cover is exploited. These uses can be as varied as agriculture, industry, recreation, or even wild life conservation.
Looking at it globally, at the scale of the earth system land-cover changes over the past three centuries can be described briefly as follows: considerable net loss of forest, a marked gain of arable cropland, partly former forest and partly from wetlands, and considerable loss of wetlands that have been partially or completely cultivated or otherwise drained and changed.
The direct impacts of these changes on the bio-geochemical budget are not yet clear. But the following can be assumed:
- The conversion from natural to human-induced systems over the past 150 years has resulted in a net flux of CO2 that is almost equal to the net release by fossil fuel burning over the same period.
- The present release of CO2 from land-cover changes amounts to about one-third of that from fossil fuel consumption.
- Land-use and land-cover changes represent the largest source of N2O emissions, which contribute to greenhouse warming and (possibly) also to stratospheric ozone depletion.
- The two largest land uses in spatial terms are crop cultivation (14 - 15 million km2) and livestock production (with pastures and range-lands, about 70 million km2). Settlements with industries cover only a small percentage of the world's land area (Turner et al. 1993).
Among the main driving forces of land-use changes, population growth, socio-economic and cultural organization, and technology play leading roles. Technological development changes the use of and demand for land resources. Other societal factors related to political and economic structures and to change in attitudes and value systems add a new dimension to environmental change, which will be illustrated by some regional examples from Africa (below).
Human impacts and industrial metabolism
Human economic activities have now reached an order of magnitude where their influence on the natural earth systems is quite significant. If we accept the analogy between biological and industrial metabolism, the latter can be defined as "the whole integrated collection of physical processes that convert raw materials and energy, plus labor, into finished products and wastes... with the economic system as the metabolic regulatory mechanism" (Ayres 1994). The firm (factory/plant) as a basic unit of the economic system can be compared to living organisms in biology. This analogy, taken a step further, leads into the notion of "industrial ecology."
Similarly, the "cycle" concept of the geo-scientists (e.g. the hydrological, carbon/oxygen, nitrogen, or sulphur cycles) can be adopted as "materials cycles" of the industrial system, starting with raw materials from the earth and returning them to nature as wastes (Ayres 1994). Industry converts primary resources into products useful for humans. In the course of these transformations, large amounts of waste are generated. It is important to measure these fluxes and processes. A number of measures of industrial metabolism have been proposed, which also require a sound knowledge of the biophysical basis. They include measurements of dissipative losses, of recycled materials, and also of the economic output per unit of material input, which can be called material productivity. Clearly, more exact measurements based on geophysical and geochemical data are desirable. This is because, collected at a sectoral level, they would allow improved analyses of the entire process of industrial metabolism. The establishment of an information system on industrial metabolism has been proposed (Fischer-Kowalski et al. 1993).
One attempt to introduce a universal measure for ecological disturbances is "materials intensity per unit of service" (Schmidt-Bleak 1992). The underlying idea is that the potential for disturbance is closely related to the mass of materials moved or processed in the whole chain of processes beginning with extraction and ending with disposal or recycling. The difference between the mass of the product itself and the total mass moved indirectly in the chain has been given the evocative term "rucksack." The size of the rucksack of a material product is a rough measure of the potential for disturbance resulting from its production and use.