Geography. Козлова Е.П. - 88 стр.

                               17.5 Climate and Man

      It’s easy to think of the earth’s climate as unchanging, and for many purposes
this would be an adequate assumption. However, the climate does change, slowly but
continually. Paleoclimatologists have found convincing evidence of major climatic
variations. Recorded history going back some 2,000 years clearly shows changes in
climate and their effects on man, animals, plants and the landscape. Great migrations
of people and animals accompanied periods of unusual cold and prolonged droughts.
The movement of plant communities toward different latitudes and different
elevations indicate important alterations in climate. The rise and fall of lake levels,
particularly those more or less closed from the sea, show period of wet or dry climate.
The extent of sea ice and its effect on shipping to the ports of northern Europe point
to the warming or cooling of the earth’s atmosphere.
      There is no doubt that climate changes continually, and that it did so long before
man and his technology came on the scene.
       Until fairly recent times, man’s effect on climate must have been insignificant.
The discovery and the Industrial Revolution signalled the start of man’s competition
with nature on a major scale. Internal combustion engines using such fossil-fuel-
powered furnaces and so forth, began to introduce into the atmosphere huge masses
of gases, particles, and grey amounts of heat.
      As the population of the earth has been increasing at an alarming rate, the
quantity of pollutants put into the air has done likewise. There is growing conviction
that the increasing concentrations of carbon dioxide and particles put into the
atmosphere by human activities are playing an important role in causing changes in
climate. Theoretical analysis have shown that small changes in the cloud cover of the
earth can have important effects on the air temperature near the ground. Atmosphere
pollution might be affecting climate by causing changes in the cloud cover.

                              17.6 Temperature Scales

      Daniel Gabriel Fahrenheit (1686 – 1736) gave his name to the temperature scale
which is still used in some weather reports. Fahrenheit was a scientific- instrument-
maker from Holland. Here is a belief that one day a cold winter wind came through
the window of his room and froze his tea with milk on the table. This made him
think of artificial mixtures of low temperatures. The lowest temperature Fahrenheit
could produce in his experiments was with a freezing mixture: the scientists mixed
ice and ammonium chloride. He called this temperature 0 0F (0 degree Fahrenheit) on
his temperature scale. Ice melted at 32 0F and normal human blood temperature was
96 0F. The improved modern version of the Fahrenheit scale uses 32 0F and 212 0F, as
the lowest and highest points on the scale. The scale became popular both in Britain
and through out the English-speaking world.
      Actually, the Celsius temperature scale is taught in all modern schools today. It
was introduced in 1742 by the Swedish astronomer Anders Celsius (1701 – 1744),
who chose the melting point of the ice as 0 0C and the boiling point of water as
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