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ecology is a priority. the ecological problem is one of the pressing problems of our days. it is closely linked to the problems of economic growth, progress in science, and technology, natural resources, energy and food supplies. in many cases the environmental problem has become a dominant one in relation to many others. the pollution of the environment, the destruction of ecosystem, the extinction of many species of plants and animals have now reached threatening proportions. an increasing influence on nature and the application of new technological processes may cause catastrophic results. it may disrupt nature's basic cycles and undermine the self-generating capacities of the biosphere and of its individual components. the accumulation of carbon dioxide in the atmosphere has increased globally by 20 per cent. As a result of the formation of a layer of carbon dioxide around the Earth the threat of unfavourable changes in climate has arisen that may transform our blue planet into an enormous greenhouse during the next decades, with possibly catastrophic effect. Those include changes in its energy balance and a gradual increase in temperature that will transform fertile regions into arid ones, raise the level of water in the oceans (through the melting of polar and drifting ice) and produce a flooding of great numbers of coastal lands and cities. The threat of a disruption in the oxigen balance has arisen through the destruction of the ozone screen in the lower stratosphere as a result of supersonic The threat of a disruption in the oxygen balance has arisen through the destruction of the ozone screen in the lower stratosphere as a result of supersonic aircrafts. Its destruction by 50 per cent will increase ultraviolet radiation 10 times corresponding influences on the sight of animals and humans.

the greenhouse effect.

The 'greenhouse effect' describes the build-up in the atmosphere of pollutant gases which block heat coming from the earth, sending the heat back to the earth's surface rather than allowing it to escape into space. The consequences of the resulting increase in global temperature could be extremely disturbing.

How the greenhouse effect works/

the sun is the most important source of energy for the earth, sending a spectrum of radiation to the planet, as X-rays, ultraviolet and visible light, infra-rad radiation, microwaves and radio waves. Much of this energy arrives as visible light.

Carbon dioxide, which is present in small quantities in the earth's atmosphere, allows visible light to pass through it. The light waves are absorbed by the earth, which in turn emits radiation, but mostly of a longer wavelength-as infra-red radiation, or reflects it back to where it came from.

CO 2 thus works in the same way as glass in a greenhouse, allowing solar radiation to pass through it, but then holding back the longer wavelength radiation that attempts to return. The result is a warmer temperature in the greenhouse than outside it.

This is a natural process, and an essential system for maintaining the earth's temperature. Without carbon dioxide in the atmosphere, the earth's surface would cool very rapidly at night, much more rapidly than at present. On the other hand, increasing or reducing the amount of carbon dioxide in the atmosphere could increase or slow down the speed at which this greenhouse effect occurs

On the other hand, increasing or reducing the amount of carbon dioxide in the atmosphere would increase or slow down the speed at which this greenhouse effect occurs. This appears to be happening at the moment: and the process is exacerbated by the presence in the atmosphere of other substances which act in the same way as CO2.

Carbon dioxide is emitted into the atmosphere partly by burning wood but primarily by burning fossil fuels (i.e., coal and oil). This is a significant annual to the CO2 already in the atmosphere.

If the greenhouse theory is correct, then a build-up of carbon dioxide in the air would be accompanied by an increase in temperature around the world.

II. Possible consequences.

If atmospheric carbon dioxide levels double, it is assumed that the mean surface temperature of the globe would increase by between 1.5 and 4.5 degrees C, witch means that in a period spanning half a human generation, there would be a global warming greater than has occured throughout the history of humanity.

A temperature increase of such a scale is so alien to human experience that it is very difficult to forecast the outcome. A number of scenarios have been outlined, however, none of which are particularly comforting:

Serious climatic changes

large areas of the world will experience climatic shocks: some region may lose up to 30 per cent of their annual rainfall-with concomitant problem relating to agriculture, food supply, forest health, soil moisture, drinking-water supply Other areas may gain 60 per cent in annual rainfall-with problems caused by storm damage, agricultural loss, flash flooding, and implications for public health.