The atmosphere has constantly changed through geologic time. Chemical
reactions using gases have always occurred. Organisms seem to evolve
their structure to the atmosphere. Every organism on Earth interplays
with these ever-changing environments.
For instance, humans have changed their atmosphere in the short time
we have been on Earth. As we discovered fire and created a use for
different forms of energy we also change our atmosphere. As we discharge
substances into the atmosphere, we can change its vertical structure,
which may cause harm later on.
One of the concerns of our atmosphere today is the deterioration of
the ozone layer which protects us from excessive ultraviolet radiation.
There is a thinning of ozone over Antarctica that occurs each Antarctic
spring. Up to 70% of the ozone normally found over Antarctica is
destroyed. Some of the reasons for this depletion are complex. Evidence
that human activities affect the ozone layer has been building up over
the last 20 years, ever since scientists first suggested that the
release of chlorofluorocarbons (CFCs) into the atmosphere could
reduce the amount of ozone over our heads. But could it be other
factors? How we affect it and to what degree is still being monitored
Ozone thinning in the Antarctic