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The earth s climate has been stable since the
last ice age. However, this climate has been observed to be
changing. Latest scientific evidence compiled by the Inter
Governmental Panel on Climate Change, a scientific panel put
up by UNEP and the World Meteorological Organization
indicates that the earth s surface temperature this century
is clearly warmer than any other century during the last
thousand years. The three warmest years during the last
hundred years have occurred in the 1990 s and the 12 warmest
years have occurred since 1983. There is also evidence that
precipitation patterns are changing and that sea level is
increasing and that the incidence of extreme weather events
(drought and floods) is increasing in some parts of the
world.
Almost every human activity conducted here
on earth affects the atmosphere except perhaps coughing. If
you drive to work, take a bath, cook a meal, grow rice, use
fertilizer, graze cattle, etc you are automatically
releasing a series of gases called greenhouse gases that are
responsible for the much talked about climate change .
So what are greenhouse gases and how do
they cause climate change? Greenhouse gases are gases such
as Carbon dioxide, methane and Nitrous Oxide, which are
released when we burn fossil fuels like wood, charcoal and
petroleum products. These gases, when released into the
upper levels of the atmosphere, trap heat emitted by the
earth s atmosphere; heat which is supposed to escape into
outer space. This results in warming in the lower levels of
the atmosphere. These gases are called greenhouse gases
because they have the same effect that the greenhouse has in
trapping heat emitted by the earth s surface. This warming
is actually what is resulting in climate change.
The most visible effects of climate change
will be changes in the rainfall patterns (droughts, floods)
an increase in global temperatures, melting of ice in cold
climates and rise in sea levels which is feared to submerge
small island status. These effects will impact on
agriculture, human health, human settlements and ultimately
global economy.
In part II and III of this article we will
talk about who the culprit in the climate change issue is
and what can we do to avert climate change.
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