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Introduction




Now, after flights of science and fancy to other world, let us come back to the Earth, the object of most sciences, the origin of life, intelligence and civilization. It is sometimes compared nowadays to a spaceship with a closed ecological system. The comparison is not intended as a figure of speech, but rather to bring home the fact that the resources present in the system must be recycled if the system is toprovide for the needs of the creatures that live on this planet. The problem at issue — man and his environment — has now become the focus for most sciences not because it is fashionable, as Freeman Dyson puts it, but because of its great significance for the whole of mankind. The discussion below is based on articles published in "Scientific American'' and includes the following items: A. The Biosphere: Its Definition, Evolution and Possible Future. B. The Environment: Problems and Solutions. C. The Biosphere: Natural, Man-Disturbed and Man-Initiated Cycles. D. What is What, or Definition of Terms?

1. The idea of the biosphere was introduced into science rather casually almost a century ago by the Austrian geologist Eduard Suess, who first used the term in a discussion of the various envelopes of the earth in the last and most general chapter of a short book on the genesis of the Alps published in 1875. The concept played little part in scientific thought, however, until the publication, first in Russian in 1921 and later in French in 1929 (under the title "La Biosphere"), of two lectures by the Russian mineralogist Vladimir Ivanovitch Vernadsky. It is essentially Vernadsky's concept of the biosphere, developed about 50 years after Suess wrote that we accept today. Vernadsky considered that the idea ultimately was derived from the French naturalist Jean Baptiste Lamarck, whose geochemistry, although archaically expressed, was often quite penetrating.

2. The biosphere is defined as that part of the earth in which life exists, but this definition immediately raises some problems and demands some qualifications. At considerable altitudes above the earth's surface the spores of bacteria and fungi can be obtained by passing air through filters. In general, however, such "aero-plankton" does not appear to be engaged in active metabolism. Even on the surface of the earth there are areas too dry, too cold or too hot to support metabolizing organisms, the only exception being technically equipped human explorers, but in such places also spores are commonly found. Thus, when viewed as a terrestrial envelope, the biosphere obviously has a somewhat irregular shape, inasmuch as it is surrounded by an indefinite "parabiospheric" region in which some dormant forms of life are present. Today, of course, life can exist in a space capsule or a space suit far outside the natural biosphere.

Such artificial environments may best be regarded as small volumes of the biosphere nipped off and projected temporarily into space.

3. What is it that is as special about the biosphere as a terrestrial envelope? The answer seems to have three parts. First, it is a region in which liquid water can exist in substantial quantities. Second, it receives an ample supply of energy from an external source, ultimately from the sun. And third, within it are interfaces between the liquid, the solid and the gaseous states of matter. Important as these three conditions for the existence of a biosphere may be in terms of historical evolution it is not the history that we are concerned with at this point but rather what the future developments are likely to be...

4. Without taking too seriously any of the estimates that have been made of the expectation of the life of the sun and the solar system it is evident that the biosphere could remain habitable for a very long time, many times the estimated length of the history of the genus Homo, which might be two million years old. As inhabitants of the biosphere we should regard ourselves as being in our infancy. Many people, however, are concluding on the basis of mounting and reasonably objective evidence that the length of life of the biosphere as an inhabitable region for organisms is to be measured in decades rather than in hundreds of millions of years, with the fault being entirely that of our own species. It would seem not unlikely that we are approaching a crisis that is comparable to the one that occurred when free oxygen began to accumulate in the atmosphere

5. . Admittedly there are differences. The first photosynthetic organisms that produced oxygen were probably already immune to the lethal effects of the new poison gas we now breathe. On the other hand, our machines may be immune to carbon monoxide, lead and DDT. But we are not. Apart from a slight rise in agricultural productivity caused by an increase in the amount of carbon dioxide in the atmosphere, it is difficult to see how the various contaminants we are polluting the biosphere with could form the basis for a revolutionary step forward. Nonetheless, it is worth noting that when the eukaryotic cell* evolved in the middle Precambrian period**, the process very likely involved an unprecedented new kind of evolutionary development. Presumably if we do want to continue living in the biosphere we must also introduce unprecedented processes.

6. The necessity of quite a new approach to the biosphere was realized by Vernadsky as early as the mid-forties. For not only was he the founder of modern biogeochemistry but he was also a man of deep scientific penetration and insight who could foresee the unavoidable long-range impact of production activities of man on the biosphere. According to him man has become a geological and biological factor by far exceeding everything that preceded him throughout evolution, the rate of his intervention in nature steadily increasing. Yet it was with optimism he looked ahead when he wrote: "I think we undergo not only a historicalbut also a planetary change as well. We live in a transition to the noosphere." By "noosphere" Vernadsky meant the envelope of mind that was to supersede the biosphere, the envelope of life. Unfortunately the quarter-century since those words were written has shown how mindless most of the changes wrought by man on the biosphere have been. Nevertheless Verna sky’s transition in its deepest sense is the only alternative to man's cutting his life-time short by millions of years.


Task 16.Read text B « The Environment: Problems and Solutions» and write the abstract to it.

Text B

The Environment: Problems and Solution

1. Should anyone attempt a brief characterization of present-day environmental problems, he would find it beyond the competence of an individual scientist. For the environmental situation has long become a subject of separate and joint research efforts of biologists, chemists, and biochemists who have to combine their knowledge with the information supplied by students of geology, oceanography and meteorology, with experts in sociology, psychology and philosophy hurriedly joining in. Yet, if stated briefly, one of the causes of the present-day environmental situation should be sought in the lack of a balanced development of particular fields of knowledge, and of an adequate picture of the intricately operating whole which is our planet.

 

The rapid and ever-growing advances in certain highly specialized fields have brought mankind far ahead of our general fundamental knowledge of the long-range effect of some technological developments, spectacular though they may appear, especially of their interplay interdependence. It is man's intervention in nature that has singled him out from the rest of the animal world since his early days. It is this very intervention that has landed him nowadays in this highly technological world of ours, with the rate of progress in particular applied fields being faster than that in our fundamental knowledge of the general operation of the Earth. It is precisely this discrepancy between the two rates which seems to be at the root of most of today's problems. This is by no means an exhaustive explanation, ignoring as it does, the social factor.

 

2. The threat to his environment is a second major problem man is faced with in the mid-20th century, the first being a menace of a nuclear catastrophe. What is so peculiar about the environmental problem when compared to the other one? Surely not its global character and everybody's involvement. A nuclear catastrophe, as seen nowadays by practically everybody everywhere, would inevitably involve every country, no matter how small or big it is, and would concern every individual, whatever secluded life he might be living. Should it happen, its inescapability is too obvious to be disputed. So is its explosive character. In contrast to this, the environmental crisis is of a cumulative nature. It is just the obscure and intricate pattern of the interaction of all factors that makes it so dangerous. Neither for any single action taken, or decision made, can bring about an immediate catastrophe, nor there be the last straw or the last step that would set in motion an avalanche of irreversible and immediate events leading to the ultimate gloomy end. It is only step by step that we approach the critical point, were there such a thing as "point" in this context.

 

3. Consequently, what is needed first and foremost is that we realise the possible adverse impact of the long-range effects of our actions, however noble the motives may seem to us at present, on the entire human race. Out of this realization may come an entirely new approach to the problem, the new approach as proclaimed by Vernadsky of the biosphere governed and operated in accordance with the laws of the human mind? Next comes the urgent need for basic research to get more profound knowledge of the cause-effect relationship, the time factor necessarily taken into account, in the whole realm of human environment, natural, man-disturbed and man-initiated. Fundamental and irreversible as they may often be the changes in our environment are not likely to bring mankind to the brink of annihilation overnight. It would take us some time yet to reach there. So let us use the time for learning how to preserve our planet in good shape and in running order for an indefinitely long time.

 

Task 17.Read text D « The Biosphere: Natural, Man-Disturbed and Man-Initiated Cycles » and write the abstract to it.

 

Text D

The Biosphere: Natural, Man-Disturbed and Man-Initiated Cycles

1. When considered dynamically, the biosphere appears an arena of complex interactions among the essential natural cycles of its major constituents, with continuous fluxes of these constituents entering the biosphere, or being released by it. Once brought into being by evolution from an inorganic environment, the living matter has profoundly altered the primitive lifeless earth, gradually changing the composition of the atmosphere, the sea, and the top layers of the solid crust both on land and under the ocean. Since then, was one to ascribe a single objective to evolution it would be the perpetuation of life. This is the single end the entire strategy of evolution is focused on, with evolution dividing the resources of any location, including its input of energy among an ever increasing number of different kinds of users, which we recognize as plant and animal species.

 

2. What are the chemical elements that prove to be the essential constituents of the biosphere? The periodic table lists more than 100 chemical elements. Yet as defined by ecologists the biosphere is the locus of interaction of only four of them: hydrogen, carbon, nitrogen and oxygen, these four being numbered 1, 6, 7 and 8 in the periodic table. Although dealing handsomely with much of the chemistry of life, this definition turns out to be a little too restrictive, ignoring as it does, the biochemical role of sulfur and phosphorus. But when enlarged to include these two, it does not go any farther up the table than element No. 16. Thus, it is a fact that most problems, the environmental ones anyway, arise from the exceptional reactivity of six of the 16 lightest elements, with the first four actually forming protein molecules, sulfur being the "stiffening" in protein and phosphorus supplying the "high-energy bond", the universal fuel for all biochemical work within the cell.

 

3. If the biosphere is to continue in running order, the biologically important materials must undergo cyclic changes so that after utilization they are put back, at the expense of some solar energy, into a form in which they can be reused. So far it has been nature that saw to it that the whole arrangement went on smoothly, all cycles being governed by complex mechanisms that were fitted together and held the whole in balance. Yet during the few last decades the intervention of man in the natural cycling of that unique compound we call living matter, has been going on an unprecedented scale and at an unprecedented rate. Never before has nature been tempered with in such a drastic and not infrequently, irreversible way, with both immediate consequences an ultimate implications not even vaguely foreseeable. For too little do we know for certain about the way nature has been self-regulating for millions of years since life began, and too many variables are involved, to be able to foresee the final impact of our rapid technological development on the biosphere as an abode of life.

 

4. Thus, what is now recognized as a threat to our environment is caused primarily by disturbances either in the natural cycles of the six essentials, or in the energy cycle of the biosphere, energy being the driving engine of all life processes.

 

5. To cite but a few examples of such man-disturbed cycles of the biosphere let us consider very briefly the energy cycle. The energy that sustains all living systems is solar energy as fixed in photosynthesis and held briefly in the biosphere before being reradiated into space as heat. It is solar energy that moves every living thing on the earth. The total amount of solar energy fixed on the earth sets one limit on the total amount of life, with the patterns of flow of this energy through earth's ecosystems setting additional limits on the kinds of life on the earth. Increasing at an unprecedented rate now is the fraction of thetotal energy required by expanding human activities, which, paradoxical as it may seem, make large segments of it less useful in support of man. Not only is man replacing the earth's major ecosystems with cities and land devoted to agriculture, but leakage of toxic substances from man - dominated provinces of the earth is reducing the structure and self regulation of the remaining natural ecosystems. The trend is progressive. Easily available to man is a smaller and smaller fraction of the earth's fixed energy, and an unavoidable question arises as to how much of the energy that runs the biosphere can be diverted to the support of a single species: man.

 

6. Or take another example — the disturbance of the nitrogen cycle. Although man and other land animals live in an ocean of air that is 79 per cent nitrogen, their supply of food is limited more by the availability of fixed nitrogen than by that of any other plant nutrient. By fixed is meant nitrogen incorporated in a chemical compound that can be utilized by plants and animals. Naturally this is done by the comparatively feworganisms that have the ability to convert the element to a combined form. Of all man's recent interventions in the cycles of nature it is the industrial fixation of nitrogen that far exceeds all the others in magnitude. Before the large-scale manufacture of synthetic fertilizers and the wide cultivation of the nitrogen-fixing legumes one could say with some confidence that the amount of nitrogen removed from the atmosphere by natural fixation processes was closely balanced by the amount returned to the atmosphere by organisms that convert organic nitrates to gaseous nitrogen. Now one cannot be sure that the denitrifying processes arekeeping pace with the fixation processes. Nor can one predict all the consequences, were nitrogen fixation to exceed denitrification over an extended period. We do know that excessive run-off of nitrogen compounds in streams and rivers can result in "blooms" of algae and intensified biological activity that deplete the available oxygen and destroy fish and other oxygen-dependent organisms, the process known nowadays as eutrophication.

 

7. Added to the natural cycles of the biosphere are man-initiated processes which may also be regarded as cycles of the biosphere, namely the production of energy, food and materials on a commercial scale. For as soon as these commodities began to be produced in quantity their production, utilization and disposal have become comparable with the cycling of natural essentials, and a challenge to mankind. To take but one example of the problems involved, think of the urgent need to get rid of all steel in use after its utilization. If properly cycled, all metal, glass, paper, fabrics and the like could provide raw materials for different industries. From a purely technological point of view man could in principle live comfortably on a combination of his own trash and the leanest of earth substances by processing tons of rock to obtain a gram of a useful mineral. Such a way of life would create new problems, because under those circumstances man would become a geological force transcending by orders of magnitude his present effect on the earth. Different as the world might become from the present one, there is no reason a priori why it would be necessarily unpleasant.

 

8. Man has it in his power technologically to maintain a high level of industrial civilization, to eliminate deprivation and hunger and to control his environment for many millenniums. His main danger is that he will not learn quickly enough and that he will not take adequate measures in time to forestall situations that will be very unpleasant indeed.

Part 4


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