WHAT IS AN ECO-SYSTEM?
The Earth is the home of all living creatures belonging to different species. This is a fact; one which is quite evident. Still, we would do well to emphasize it as forcefully as possible. For, the Earth is being so badly misused and exploited everywhere that it may cease before long to serve as our home. Should that ever happen, we shall ourselves be destroyed. For we continue to live only as long as the Earth is in a position to support us.
Definition and Nature
We would do well to promote a very sharp kind of an 'Earth Consciousness'. In fact, this is very important for our future and that of the subsequent generations. We cannot possibly afford to violate what is commonly known as 'Human Ecology' or the 'Ecosystem'. The Word 'Ecology' has two Greek roots: 'Oikas' which means house and 'Logos' which means discourse. As such, Ecology or the eco-system can be defined as 'a study of the habitat of a living organism like man'. More precisely, The Shorter Oxford English Dictionary defines it as 'The branch of biology which deals with the mutual relations between organisms and their environments'. This, however, is only the first of the two definitions given by the Dictionary. The other speaks of it as 'AH the mutual relations taken collectively'. In this way, ecology can be taken to mean the global eco-system itself.

Importance of Eco-system

The eco-system, as we have seen, deals with the inter-relationship of the living organisms with their environments. It has also been mentioned that the relationship is reciprocal and poised delicately. There is, so to say, a balance between the living organisms and their surroundings. When we talk of threats to the eco-system, we essentially mean that this natural balance between the living beings and their surroundings is threatened by the actions of man—the highest of living beings and to this extent, the eco-system is

ECOLOGICAL CRISIS

When we speak of the 'Crisis' of ecology, what we have in mind is the crisis which the global eco-system is now facing. This crisis is brought about, essentially, by man's depredations and unlawful encroachments upon the environment. It is easy to see that it is very much in our interests to preserve the integrity of this system; for this system is so sensitive that some of the apparently localized environmental abuses may well cause it to break down.

Two simple examples would make things clearer; i.e., we would get a more coherent picture of the ecological crisis. The first of these concerns the use of pesticides or chemical poisons used for killing plant pests. In the long run these will be killed and agricultural output will increase. However, this is only a short-term gain. For gradually, pests will develop their own defence system and put up resistance. Consequently, even stronger varieties of these poisons will have to be produced and used in larger quantities. A sort of a vicious circle will begin to operate. This implies that the quantities of the poisons needed merely to maintain the agricultural output at a given level will continue to increase.
But, there is another difficulty also; this lies in the fact that once used, these poisons become toxic. They do not get degraded. This is, no enzymes are available in the Earth system to break down these chemicals and render them harmless. Once used, they last for ever and accumulate in organic matter everywhere. For instance, residues of pesticides used in the United States have been found in the milk of the nursing mothers. Also, in the bodies of the Penguins which are found close to the South Pole. Similarly, the radioactive and cancer-causing wastes of nuclear power plants released by the British Nuclear Fuels Ltd. into the Irish Sea are known to move to the Baltic Sea.
The second example concerns what is called the 'Greenhouse Effect'. A green house, also known as a hot house, is a building with roof and walls of glass. It is used for growing flowers and plants which need more of warmth than ordinary plants. With the sunshine which enters the greenhouse, the plants produce carbon dioxide. But this gas gets caught within the greenhouse and continues to absorb the solar heat coming from outside. In this way, the temperature inside the greenhouse can be raised sufficiently to promote plant growth.
A similar phenomenon can be observed on a global scale. Although carbon dioxide forms no more than 0.03 per cent of all the gases in the atmosphere, it performs a most important function and in fact, makes life on the Earth possible. This is easy to see. When the Sun s energy comes in contact with the Earth's atmosphere, much of it just bounces back. But some of it is absorbed by the carbon dioxide present in the atmosphere. The surface of the Earth is thus, warmed sufficiently to make life possible.
But, now, something very dangerous is taking place. As more and more of fossil fuels such as coal and oil are burnt in various ways, carbon dioxide locked up in those fuels for the last millions of years is released into the atmosphere. With the burning of the tropical forests, still more of it is produced. Thus, in 1850, the Earth's atmosphere had only 265 parts per million of this gas. It now has 340 parts and if it continues to remain unchecked, this figure could well rise to 600 by the middle of the next century. As a result, the Earth would become much warmer than now. Indeed, the polar temperatures could rise by 7 degrees centigrade. This, in turn, would cause the polar ice caps to melt and the water level in the oceans to rise by five to seven meters. Large parts of the Earth's land surface would be flooded, and in fact, be permanently submerged under water. Many big cities of the world like Calcutta, Bombay, and London, New York would be wiped out.
This is now recognized to be one of the most serious dangers to the world. Therefore, once we begin to take note of it, we cannot but question the validity of the prevailing civilization itself. For, given the way it is heating up the global atmosphere, it promises to destroy the very basis of human existence. This means that w& should take care to reexamine development and growth, development plans, development theories and so on.

BIOSPHERE

The need for a re-examination of the type mentioned in preceding lines becomes even clearer if we take into account not just the global atmosphere, but the whole of the Biosphere. The Biosphere, as you probably know, is the sphere of life around the Earth and includes within itself the atmosphere, the oceans and the soil, each one of which, in turn, contains countless variety of life forms.
Like every other life-form, we are very much a part of this biosphere. But, unlike any other life-form that the Earth has ever supported, we also have the power to modify it with all that we continue to do. This means that like all other life-forms, we are an integral component of the biosphere and draw our sustenance from it. Unlike all other life-forms, we are still not and cannot be completely integrated into it.