1. Greenhouse effect
Global warming

2. Greenhouse effect and global
warming
Carbon dioxide and water vapor are natural
components of air. As such, they have
generally not been considered pollutants.
However, the voluminous amount of carbon
dioxide and water continously spewed into
the air by motor vehicles and factories
worldwide has become alarming.

3. Greenhouse effect and global
warming
Increased amounts of carbon dioxide and
water vapor have possible long term effects.
The maxima of solar radiation which enters
the earth is in the shorter wavelenght
ultraviolet and visible regions.

4. Greenhouse effect
The earth also radiates enrgy butits
maxima is in the longer wavelenght
infrared region
Both carbon dioxide and water
vapor molecules are not by
affectedby incoming shorter
wavelenght solar radiation but they
absorb heat (infrared radiation)
given off by the earth.

5. Greenhouse effect and global warming
This heat is released back to the lower
atmosphere as their molecules vibrate.
This is called the greenhouse effect.
Both carbon dioxide and water vapor are
called greenhouse gases.

6. Greenhouse effect and global warming
But there is less problem with water vapor
because its concentration in air remains fairly
constant. On the other hand, the amount of
carbon dioxide in air has tremendously
increased in the past century because of
man’s activities, mainly the burning of fossil
fuels about 3 g of carbon dioxide is produce
for every gram of fossil fuel burned.

7. Ozone depletion

8. Ozone Depletion
Ozone depletion describes two distinct but
related phenomena observed since the late
1970s: a steady decline of about 4% per
decade in the total volume
of ozone in Earth's stratosphere (the ozone
layer), and a much larger springtime decrease
in stratospheric ozone over Earth's polar
regions.

9. Ozone Depletion
The latter phenomenon is referred
to as the ozone hole. In addition to
these well-known stratospheric
phenomena, there are also
springtime polar tropospheric
ozone depletion events

10. Ozone Depletion
It is suspected that a variety of biological
consequences such as increases in skin
cancer, cataracts,[3] damage to plants, and
reduction of plankton populations in the
ocean's photic zone may result from the
increased UV exposure due to ozone
depletion.

11. Ozone Depletion