This document discusses global warming and its causes. It explains that global warming is an increase in the earth's temperature due to excess greenhouse gases trapping heat in the atmosphere. The main greenhouse gases are carbon dioxide, methane, nitrous oxide, CFCs, and ozone. Human activities like burning fossil fuels and deforestation have increased greenhouse gas levels, enhancing the greenhouse effect and causing global warming. Evidence of global warming includes melting glaciers, rising sea levels submerging islands, and changes in plant and animal environments. The document also covers the ozone layer, nuclear radiation and energy.

1. Global
Issues
Presentation by: Harmandeep, Thang, Safir

2. 9.1
Global 4000
Warming
The Fact:
islands in Indonesia will drown in the upcoming years
due to rising sea levels caused by Global Warming.

3. What is Global Warming?
Global Warming refers to the increasing temperature of
earth's surface due to the excess heat trapped into our
atmosphere. This takes place due to enhanced green house
effect.

4. What is Greenhouse effect?
The phenomenon whereby the earth's atmosphere traps
solar radiation, caused by the presence in the atmosphere
of gases such as carbon dioxide and methane that allow
incoming sunlight to pass through but absorb heat radiated
back from the earth's surface. This keeps the Earth warm
and a nice place to live in, keeping us all happy.

5. “Enhanced” greenhouse effect
These days, human activities produce too much greenhouse gases
that makes the earth’s atmosphere thicker, making it impossible for
the Sun rays to reflect back into the atmosphere. Hence, the Sun rays
get stuck into the earth's atmosphere, making it too hot to live in. This
is called Enhanced Greenhouse Effect and is what's
causing Global Warming.

6. Greenhouse Gases
-
Carbon-dioxide
Methane
Nitrous Oxide
Chlorofluorocarbons
Surface Ozone

7. Carbon Dioxide
- Produced by burning fossil fuels such as
gas, petrol, aviation petrol, diesel and oil

8. Methane
-
Produced when you burp or fart.
Twenty –one times more effective
than carbon dioxide in blocking the
escape of radiant heat.

9. Nitrous Oxide
- Produced from burning forests, car
exhaust, jet fuel and artificial fertilizers.

10. Chlorofluorocarbons (CFCs)
-
Invented in 1920s.
Were found in aerosol spray cans and as coolant gases on refrigerators.
Non-poisonous.
Odourless.
Were once called ‘wonder chemicals’.
Stable and cheap to produce.

11. Surface Ozone
-
Generated as a part of photochemical smog.
Produced by the action of sunlight on motor vehicle and industrial pollution.

12. Australian greenhouse gas
production
Carbon dioxide
Methane
Nitrous Oxide
Other

13. Evidence of global warming
#1- Glaciers have been melting.

14. Evidence of global warming
#2- Icebergs are breaking off.

15. Evidence of global warming
#3- Ice sheet in Greenland is getting thinner.

16. Evidence of global warming
#4- Coral reefs in the Caribbean are now permanently bleached.

17. Evidence of global warming
#5- Alpine plant species has fallen.

18. Evidence of global warming
#6- Snowgums in Australia have shifted 40 meters up the mountain.

19. El Niño effect
El Niño effect occurs in which trade winds weaken or
reverse, allowing warmer water to move towards the
west coast of South America around Christmas time.
The result is that Australia experiences drought, and
South America experiences increased rainfall.

20. 9.3
Ozone Layer

21. What is Ozone?
Ozone is naturally occurring form of oxygen, each
molecule comprising three atoms.

22. Ozone Layer
Ozone is created when UV light splits oxygen molecules into single
atoms. These single oxygen atoms then join other oxygen
molecules to form triplets of oxygen atoms, or ozone molecules.
UV light also splits ozone molecules, so ozone is continually being
created and destroyed, with UV light being absorbed in the
process . The region, in which ozone is thinly distributed is referred
to as the ozone layer.

23. Dobson Unit
-
- Measures the thickness of the ozone layer.
A value of less than 220 DU is considered to be an
ozone hole.
If all the ozone molecules in the ozone layer were
brought to ground level, it would form a sheet
averaging only 500 DU(5mm) thick.

24. The future:
Kyoto Protocol
-
Formed in 1987 to stop manufacturing of CFCs.
One hundred nations signed up.
The agreement is expected to bring the ozone
levels back to normal by 2045.

25. 9.3
Nuclear Radiation

26. Radiation and
Radioactivity
-
An element whose atoms emit nuclear
radiation is said to be radioactive.
- Example: Uranium.

27. Atoms and Isotopes
-
Isotopes are atoms of the same element that have
different numbers of neutrons in their nuclei.
A radioactive isotope is called a radioisotope.
When referring to a radioisotope, often just its mass
number is given.
Example: Lithium.

28. Types of Nuclear Radiation
-
Alpha radiation
Beta radiation
Gamma radiation

29. Alpha Radiation
- The thrown out cluster from
radioactive nuclei is known as alpha
particle.
- Its done so to make the nuclei smaller
and more stable.
- Alpha particles move at speeds of
up to one-tenth of the speed of light.
- Alpha particles are stopped by a
thick sheet of paper or human skin.

30. Beta Radiation
- When there is an imbalance of
neutrons and protons in a
nucleus, a neutron may
change into a proton and an
electron. The newly created
electron is called a beta
particle.
- Beta radiation can be blocked
using aluminum sheet of 1mm.

31. Gamma Radiation
- Sometimes when an alpha particle or beta particle is
emitted from nucleus, the new nucleus is still unstable
and emits extra energy in the form of gamma ray to
become even more stable.
- Gamma rays can only be blocked by a thick piece of
lead or concrete.

32. Half-Life
- Half-life is the time taken for half the atoms in a
sample to decay.
- Example: quantity of radon-222 halves every four
days.

33. Carbon Dating
-
Used to date back dead organisms.
-
It is done by comparing the amounts of carbon-14 and
carbon-12 in the organism.

34. Uses of Nuclear Radiation
#1- Used in radiotherapy to treat cancer.

35. Uses of Nuclear Radiation
#2- Used to detect thickness of paper.

36. Uses of Nuclear Radiation
#3- Used in hospitals to sterilize
medical equipment.

37. 9.4
Nuclear Energy

38. Nuclear Fission
- Its when uranium hits the
neutron and as a result the
neutron becomes very
unstable and that produces
heat and energy.

39. Nuclear Fusion
- Its when tritium and deuterium combine
together releasing neutron. It produces
energy and heat.

40. Other Alternatives
#1- Solar Energy.

41. Other Alternatives
#2- Wind Energy.

42. Other Alternatives
#3- Geothermal Energy.

43. #1- Think
Green
#2- Do Green
#3- Share Green
Save The Earth