Changes in the Earth's Environment


The 20th century, especially in the second half, has been one of rapid
change in the Earth's environment. The impact of humans on the physical form and
functioning of the Earth have reached levels that are global in character, and
have done so at an increasingly mounting speed. 20 years ago the environment was
seen as posing a threat to the future of humanity as death rates from natural
hazards had increased dramatically since the turn of the century. The Earth
though has always been plagued by natural disasters. Now, with the world
population growing at a rapid rate more people are living in hazard prone areas.
Events which may have gone unnoticed previously, only become hazards when there
is intervention with humans and their lifestyle. With the discovery of the ozone
hole in the 1980's attention was now more focused on the threat humans were
posing to the environment. With scientific evidence to back up pessimistic
predictions of our future, most people, through media coverage, political
pressures and general concern now see the environment as being truly threatened
by human progress and in desperate need of help.
Natural hazards have been defined as “...extreme geophysical events greatly
exceeding normal human expectations in terms of their magnitude or frequency and
causing significant damage to man and his works with possible loss of life.”
(Heathcote,1979,p.3.). A natural hazard occurs when there is an interaction
between a system of human resource management and extreme or rare natural
phenomena (Chapman,1994). As McCall, Laming and Scott (1991) argue, strictly
speaking there is no hazard unless humans are affected in some way. Yet the line
between natural and human-made hazards is a finely drawn one and usually
overlapping. Doornkamp ( cited in McCall et al, 1992) argues that many hazards
are human induced or at least made worse by the intervention of humans.
In the 1970's, natural hazards were an important subject of topical study,
as the nature of their impact on human populations and what they valued was
increasing in frequency at quite a rapid rate (Burton, Kates, White, 1978).
During the 75 years after 1900 the population of the earth increased by a
staggering 2.25 billion people. People who needed land on which to live and work.
As the population rose people were dispersed in more places and in larger
numbers than before. The predominant movement of people being from farm to town
or city (Burton et al,1978.). It is this growing world population, Burton et al
(1978) suggest, that is the main reason behind why hazards are increasing and
were seen to pose such a threat to humankind in the 70's. While the average
number of disasters remained relatively constant at about 30 per year, death
rates climbed significantly.
As the growing world population requires the cultivation of land more prone
to hazards, more people and property are thus exposed to the risk of disaster
than ever before, and as Stow (1992) argues, the death toll inevitably rises. An
example that shows the concern that humans faced from the environment can be
exemplified by the Bangladesh cyclone of 1970, which killed approximately
250,000 people. Although part of the reason for so many deaths can be put down
to a then poorly understood process, land-use can also be implicated. Because of
a rising population, land in Bangladesh was reclaimed by the government and held
against the sea. People in large numbers were then encouraged to occupy the area.
An area which turned out to be one of great risk. Major disruption was
inevitable Burton et al (1978) argue whenever population was in the path of such
forces. Had reasonable measures been taken in advance of the storm, the material
damage, loss of life and social dislocation could have been seriously reduced.
In the 1990's we live in an information age. Today we have remarkable
monitoring and predictive capabilities for natural hazards. The use of advanced
telecommunications and emergency management, together with the exploitation of
geographic information systems in hazard mitigation has greatly reduced the
extent to which natural hazards are seen as a threat to people in the 90's
(Chapman et al, 1994). Loss of life and property from natural disasters
continue to rise though as the population of the world rises and puts more
demands on the environment for land resources. White (1974) argues that
environmental risk may be considered to be primarily a function of the value
systems of a society. How dangerous a natural hazard is, is not measured in
absolute terms but in how dangerous it is perceived to be. 20 years ago,
technology