Human Impact on the Environment

Human Impact on the Environment

About three hundred years ago there was a definite spurt in the

population of the human race. This was brought about with advancements

in sanitation and technology, as well as a dramatic fall in the death

rate. By around 1850 the world's population had grown to about 1

billion and by 1930 it had risen to 2 billion. The current figure is

around 6 billion and at this rate the United Nations estimates the

population will be at about 9 billion by 2054. This would be a 900%

increase in just 200 years.

This increase in population has meant that the world's resources have

been put under a great strain in order to sustain the human race. But

it has only been in recent years that man has looked to address the

problems he has caused and many of them are irreversible. Ever since

man learnt to hunt with weapons, species have been hunted to

extinction, and as the brain capacity of man increased so did his

expectation of living standards. This has meant an even greater effect

on the planet and has resulted in urbanisation, growth in agriculture,

and the inevitable rise in deforestation.

Deforestation is proceeding at about 17 million hectares per year.

Between 1980 and 1990 the 1.2 per cent in Asia, 0.8 per cent in Latin

America and 0.7 per cent in Africa. Although the most publicised loss

in forest is in rainforests, the UK has also suffered major forest

loss in the past 150 years. About 200 years ago 85% of the UK was

woodland and now the figure is under 8%. The reasons for deforestation

are:

· Fuel

· Urbanisation

· Agriculture

· Wood for building

Deforestation causes soil erosion...

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... are broken

down by sunlight, resulting in the chlorine reacting with and

destroying ozone molecules. For this reason, the use of CFCs in

aerosols has been banned in many countries. Other chemicals, such as

bromine halocarbons, and nitrous oxides from fertilisers, may also

attack the ozone layer. Scientists discovered that the largest problem

lay in Antarctica, where a periodic loss of ozone was located. A

similar problem was found in the Arctic and as a result the "Montreal

Protocol" was signed by 49 countries. Within it the countries declared

that they would phase out the use of CFCs by the end of the century.

In addition to this NASA launched the 7-ton Upper Atmosphere Research

Satellite. This measures ozone variations at different altitudes, and

is providing the first complete picture of upper atmosphere chemistry.