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Реферат Ecological problems. Environmental protection

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Every year the atmosphere is polluted by about 1000 tons of industrial dust and other harmful substances. Big cities suffer from smog. Cars with their engine have become the main source of pollution in industrial countries. Vast forests are being cut down for the need of industries in Europe and USA. The loss of the forests upsets the oxygen balance of the new wastelands. As the result some species of animals, birds, fish and plants have disappeared and keep disappearing.

Water pollution is very serious, too. Ugly rivers of dirty water polluted with factory waste, poisoned fish are all-round us. And polluted air and poisoned water lead to the end of the civilization. So, nowadays a lot of dead lands and lifeless areas have appeared, because our actions and dealings can turn the land to a desert.

Greenhouse effect

The greenhouse effect is the process in which the emission of infrared radiation by the atmosphere warms a planet's surface. The name comes from an analogy with the warming of air inside a greenhouse compared to the air outside the greenhouse. The Earth's average surface temperature is about 33 В° C warmer than it would be without the greenhouse effect. The greenhouse effect was discovered by Joseph Fourier in 1829 and first investigated quantitatively by Svante Arrhenius in 1896. In addition to the Earth, Mars and especially Venus have greenhouse effects.



Basic mechanism

ecological environmental protection greenhouse

The Earth receives energy from the Sun in the form of radiation. The Earth reflects about 30% of the incoming solar radiation. The remaining 70% is absorbed, warming the land, atmosphere and oceans. For the Earth's temperature to be in steady state so that the Earth does not rapidly heat or cool, this absorbed solar radiation must be very nearly balanced by energy radiated back to space in the infrared wavelengths. Since the intensity of infrared radiation increases with increasing temperature, one can think of the Earth's temperature as being determined by the infrared flux needed to balance the absorbed solar flux. The visible solar radiation mostly heats the surface, not the atmosphere, whereas most of the infrared radiation escaping to space is emitted from the upper atmosphere, not the surface. The infrared photons emitted by the surface are mostly absorbed in the atmosphere by greenhouse gases and clouds and do not escape directly to space.

The reason this warms the surface is most easily understood by starting with a simplified model of a purely radiative greenhouse effect that ignores energy transfer in the atmosphere by convection (sensible heat transport) and by the evaporation and condensation of water vapor (latent heat transport). In this purely radiative case, one can th...

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