The document discusses two main topics: 1) The greenhouse effect, which is caused by greenhouse gases like carbon dioxide trapping heat in the atmosphere similarly to how glass traps heat in a greenhouse. Concentrations of these gases have increased since the industrial revolution due to human activity. 2) The thinning of the ozone layer, which filters out UV radiation. The ozone layer has been decreasing since the 1970s due to CFCs, exposing organisms to more UV radiation and increasing health risks like skin cancer.

2. 9.2
THE GREENHOUSE
EFFECT AND
THE
THINNING
OF THE
OZON LAYER

4. • The greenhouse effect is an effect in the atmosphere as a result of
the presence of certain gases, called greenhouse gases (figure 9.2 )
• Greenhouse gases in the atmosphere are similar to the glasses
panes of a greenhouse which traps the heat and warm the
greenhouse.
• Carbon dioxide, chlorofluorocarbons (CFCs), methane, nitrous
oxide, low level ozone, and water vapour make up the greenhouse
gases.
• With the exception of CFCs, most of the greenhouse gases occurs
naturally. However, all of them are also the result of human
activities.
• Today data collection around the world show a steady increase in
the concentration of greenhouse gases. At the same time, there is
also rapid development and industrialisation.
• Since the beginning of the Industrial Revolution, atmospheric
concentration of carbon dioxide have increased by nearly 30%,
the concentration of methane have more than doubled, and
concentration of nitro oxide (N2O) are risen by about 15%.

6. A green house is used to grow
vegetables and plant in
temperature climate, especially
during winter. A greenhouse is
designed to trap solar energy.
Sunlight penetrates the glass roof
of a greenhouse to warm the soil.
However, the heat given off by the
soil cannot pass through the glass,
so it remains inside to warm the
air. This means that the heat from
the sun is trapped inside the
greenhouse and this keeps the
plant warm throughout winter.

8. YEAR TEMPERATURE
1995 26.9
1996 26.8
1997 27.1
1998 27.7
1999 26.9
2000 27.0
2001 27.1
2002 27.4
2003 27.1
2004 27.2
2005 27.3

9. OCCURRENCE OF FLOODS
*As the mean temperature rises, the
polar ice caps and glaciers melts.
*This causes a rise in the sea level.
* A rise in sea levels causes low-lying
area to be flooded.
CLIMATE CHANGE
*Global warming leads to changes in wind
direction and the distribution of rain fall. As
a result, agricultural activities are affected.
* Global warming cases weather patterns to
change. This affects the distribution of
species which may lead to the extinction of
species in certain regions.
OCCURRENCE OF DROUGHT
*Global warming increases the
frequency of droughts.
*The land becomes dry infertile.
*This lead to a drop in crop
yields.
SPREAD OF DISEASES
*With warmer climates, pests and
vectors may spread to new areas.
* The warmer condition leads to an
expansion of territories for disease-carrying
vectors, resulting in an increase
in the outbreaks of diseases such as
malaria and dengue fever.
The effect of
global
warming

10. Effect Of Global Warming On
Plants
Effect Of Global Warming On
Animals

11. Effect Of Global Warming On HUMANS

15. • The ozone layer is a region in the stratosphere,
between 20 and 25 kilometers above the
surface of the Earth.
• The ozone layer contains high concentrations
of ozone molecules (O3) that absorb ultraviolet
(UV) radiation and shield organisms from its
damaging effect.

16. The ozone layer filters out UV radiation

19. • The thinning of ozone layer has been recoded
by scientists since the 1970s.
• In 1985,it was reported that the stratospheric
ozone over the Antarctica had declined by
40% since 1977.
• The atmosphere in this area has very low
ozone concentrations, resulting in the
formation of an ozone hole. An ozone hole has
now appeared above the Arctic as well.
• Consequently, UV radiation has risen by 10%
per decade in the southern hemisphere.
• This layer of ozone shields us from excessive
ultra violet radiation from the sun.

20. Causes of ozone depletion
• The destruction of the ozone layer is mainly due to
the increasing levels of chlorofluorocarbons in the
atmosphere.
• CFCs are very active chemicals that contains chlorine,
carbon and fluorine.
• CFCs are used as coolant in air conditioners and
refrigerators, propellants in aerosol cans and foaming
agents in the making of Styrofoam packaging.

21. OZONE DEPLETION

22. The effect of ozone depletion

23. Effects on Human Health
• Over exposure may:
– Increase risk of non-melanoma
and malignant
melanoma skin cancer
• Higher risks of
malignant melanoma
from severe
sunburns –
especially in
childhood
• Risk of malignant
melanoma has
increased 10%
• Risk of
nonmalignant
melanoma has
increased 26%
Non-malignant
malignant

24. Over Exposure
– Suppress immune system
– Accelerate aging of skin due high exposure
– Cause an outbreak of rash in fair skinned people
due to photo allergy – can be severe

25. Skin Protection
• Protect the skin against the solar radiation
using skin creams with SPF
– The greater the numerical value of the SPF the
greater the protection
• Use lip balm with SPF
• Cover up

26. Over Exposure to UV-B….
• Increases the risk of
cataracts
– Induces type of
protein that provokes
cleaving (splitting) in
the lens
– Leading cause of
blindness
– The prevalence of
cataract after age 30
is doubling each
decade
• Causes pterygium
– A wedge-shaped
growth over the
central cornea

27. Manifestations of…
brought on by
over exposure to
UV-B

28. Protection
• Sunglasses with 100% UV block
• Wrap around sunglasses
• Eye protection for children
• Hats