is mounting at international level that the growth of the world's population,
coupled with expectations for higher standards of living, is depleting natural
resources and damaging the environment.
At a fundamental level, people need energy to survive. They obtain this energy from food and water, and these represent the bare minimum required for existence ~ physiological needs. As a race, however, we expect more than just to simply exist and it is the activities at work and in the home which have energy implications. Factory production, transport, heating, lighting and using electrical appliances all involve the conversion of energy from one form to another. Note that the energy is never "used up" ~ this is scientifically impossible ~ merely converted into an ultimately less useful form or degraded. The chemical energy contained within oil is converted into heat energy within the engine of a car which in turn provides the kinetic energy to propel the car along. Put your foot on the brake and this energy is converted to heat energy within the brakes. The chemical energy contained within natural gas is converted into heat at a gas fired power station which in turn powers the turbines which generate electrical energy. This energy is then converted within homes to create the heat and light from a television or the heat and sound energy from a stereo. Obviously the more "advanced" the society then the more of earth¹s natural energy resources are going to be consumed.
depend on fossil fuels such as oil, coal and natural gas for 70-80% of
our energy usage. Strenuous efforts are being made to find new sources
but these are all ultimately finite and will run out some time next century.
populations and rising living standards lead to more and more demands
on limited resources. Various initiatives have been taken by individuals,
local and national authorities, and the international community (Earth
Summit at Rio in 1992) to try and achieve "sustainable development".
more efficient use of materials and other resources, avoidance of materials and manufacturing methods that damage the environment, substitution of materials and processes by more effective ones, recycling of materials.
associated with the wasteful use of energy can be tackled in many ways.
There are particularly large gains to be made from switching to more energy
efficient cars and buildings. Engines are becoming progressively more
powerful yet more economical and cleaner than their predecessors.
The use of raw materials in the manufacture of goods is another area of environmental concern. However, the consumption of steel, cement, paper and other raw materials has been growing less rapidly than our use of energy in recent years, at least in industrialised countries. The demand for timber and wood products remains high and the clearing of forests can lead to soil erosion, flooding and the destruction of wildlife habitats. In many countries wood is a primary fuel so that large areas of forest are cleared for energy purposes. However, wood is at least a renewable material and schemes exist to plant a new tree for each one felled to help maintain stocks.
The collection, sorting and re-use of household and trade waste is widely practised. Many local authorities provide collection points for cans, glass, plastics, paper and fabrics, and techniques have been developed for seperating materials from general household rubbish. Reclaiming metals is widespread in industry and substantial quantities of steel are produced from salvage such as scrapped cars and lorries. Plastics recycling is a more recent innovation and has been assisted by the use of identification codes moulded onto plastic objects. Plastics however, degrade through recycling so that the material that was used to produce the dashboard of a car might be used in a less visible area during it's next life.
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