Sabtu, 07 April 2012

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The Importance of Rainforests
Rainforests are one of the most
complicated environments on Earth.
They are recognised worldwide as
containing the richest source of plants
and animals and are believed to contain
nearly three-quarters of all the varieties
of life on Earth. This is remarkable
because rainforests cover only about six
per cent of the Earth's land surface.
Rainforest are the oldest major
ecosystem, having survived climate
changes for more than one million
years. They provide habitats for more
species of plants, animals, insects and
birds than any other environment
found on our planet. Scientists estimate
that between 60 and 90 per cent of all
species of life are to be found in rain
forests. Unfortunately, the widespread
destruction of many of the world's
rainforests has caused a significant
decline in the number of plant and
animal species on Earth.
Rainforests influence both our
local and global climates. For example,
between 50 and 80 per cent of the
moisture in the air above rainforests
comes from the rainforest's trees. If
large areas of these lush rainforests are
cleared, the average rainfall in the area
will drop. Eventually, the area's climate
will get hotter and drier. This process
could convert rainforests into a sparse
grassland or desert.
Rainforests are also able to absorb
over 90 per cent of the rainfall in their
leaves and mosses. By doing this, they
are able to slow down water run-off by
gradually releasing the water over time
into streams and rivers. This helps to
control soil erosion and fl ooding.
Rainforests are vital to the Earth in
helping to recycle carbon and oxygen.
Carbon dioxide (CO2) is the gas put into
the air globally by humans, mainly by
the burning of fossil fuels (for example
in cars and factories). Rainforests are
able to remove carbon dioxide from the
air and return oxygen in its place. This
is why our global rainforests are often
called the Earth's ‘lungs'.
Rainforests are major producers
of the Earth's oxygen. In fact, scientists
believe that nearly 50 per cent of
the Earth's oxygen is produced by
rainforest in the Amazon region alone.
Nearly 40 per cent of the world's
carbon is contained in the trees of
the rainforests. As rainforests are cut
down and burned, carbon dioxide is
released into the Earth's atmosphere.
Eventually, as this gas builds up the
atmosphere, leading to what scientists
call the enhanced greenhouse effect.
To sum up, the role of the rainforest
is essential for human life. It creates
equilibrium in our environment and
its resources are signifi cant for human
beings survival.
                                                                Taken from SOSE: Studies of Society and Environment, 2000

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