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1. Global warming has become perhaps the
most complicated issue facing world
nowadays.

2. What is global warming?
The Planet Is Heating Up—and Fast

3.  The earth heats up (the temperature rises)=> It
happens when greenhouse gases (carbon dioxide,
water vapor, nitrous oxide, and methane) trap heat
and light from the sun in the earth’s atmosphere,
which increases the temperature. This hurts many
people, animals, and plants.

4. What is the greenhouse effect?
•The greenhouse effect is when the temperature rises
because the sun’s heat and light is trapped in the earth’s
atmosphere.
•The heat and light can get through the atmosphere, but it
can’t get out. As a result, the temperature rises.
•Sometimes the temperature can change in a way that helps
us.

5. The greenhouse effect makes the earth
appropriate for people to liveon.

6. Without it, the earth would be freezing=>, It would be
freezing at night because the sun would be down. We
would not get the sun’s heat and light to make the night
somewhat warm.

7. On the other hand it would be burning hot .=> During the day,
especially during the summer, it would be burning because the
sun would be up with no atmosphere to filter it, so people, plants,
and animals would be exposed to all the light and heat.

8. What is global warming doing to
the environment?
 Makes the sea rise : the water covers many low land
islands, the plants and causes some of them to die so,
the animals lose a source of food, along with their
habitat,but people lose two sources of food, plant food
and animal food

9. Global warming, is harming and killing algae in the
ocean.=> Fewer algae is a problem because there is less
food for us and many animals in the sea.

10. One thing that causes global warming is electrical pollution, fossil
fuels are burned to create electricity. Fossil fuels are made of
dead plants and animals. Many pollutants are sent into the air
when fossil fuels are burned. Some of these chemicals are called
greenhouse gasses.
•The pollution that causes global warming is linked to acid rain. => Acid rain
gradually destroys almost everything it touches

11. Another thing that makes global warming worse is when
people cut down trees. Trees and other plants collect
carbon dioxide (CO2), which is a greenhouse
gas.(deforestration)
Global warming=> it is also destroying many huge
forests,many more fires that wipe out whole
forests. This happens because global warming can
make the earth very hot.

12.  Carbon dioxide is the air that our body lets out when we
breathe. With fewer trees, it is harder for people to
breathe because there is more CO2 in the air. Plants
collect the CO2 that we breathe out, and they give back
oxygen that we breathe in. With less trees and other
plants, such as algae, there is less air for us, and more
greenhouse gases are sent into the air.

13. What are people doing to stop
global warming?
 Carpooling=>is driving with someone to a place that
you are both going to. This minimizes the amount of
greenhouse gases put into the air by a car.
 Another thing that people are doing is being more
careful about leaving things turned on like the
television, computer, and the lights.

14. The Clean Air Act is making many companies change their products to decrease
these problems. Part of the law says that you may not put a certain amount of
pollutants in the air.
The Clean Air Act has also made car companies change some of the things
inside of the cars. Cars pollute a lot. While cars make more than half of the
world’s smog.
•Reducing cars, buses, and trucks which are also responsible for over 50% of
dangerous chemicals let into the air
•Ozone - Ozone is produced when other pollution chemicals combine. It is the basic
element of smog.
•It causes many different kinds of health issues dealing with the lungs.
• It can damage plants and limit sight. It can also cause a lot of property damage.

15. If we want to live longer,to be safer
and in good health we must protect
our environment

16. How much have we increased the Atmosphere's CO2 Concentration?
Human beings have increased the CO2 concentration in the atmosphere
by about thirty percent, which is an extremely significant increase, even
on inter-glacial timescales. It is believed that human beings are
responsible for this because the increase is almost perfectly correlated
with increases in fossil fuel combustion, and also due other evidence,
such as changes in the ratios of different carbon isotopes in atmospheric
CO2 that are consistent with "anthropogenic" (human caused) emissions.
The simple fact is, that under "business as usual" conditions, we'll soon
reach carbon dioxide concentrations that haven't been seen on Earth in
the last 50 million years.

17. Combustion of Fossil Fuels, for electricity generation, transportation, and heating,
and also the manufacture of cement, all result in the total worldwide emission of
about 22 billion tons of carbon dioxide to the atmosphere each year. About a third of
this comes from electricity generation, and another third from transportation, and a
third from all other sources.
This enormous input of CO2 is causing the atmospheric levels of CO2 to rise
dramatically. The following graph shows the CO2 levels over the past 160
thousand years (the upper curve, with units indicated on the right hand side of the
graph). The current level, and projected increase over the next hundred years if we do
not curb emissions, are also shown (the part of the curve which goes way up high, to
the right of the current level, is the projected CO2 rise). The projected increase in CO2
is very startling and disturbing. Changes in the Earth's average surface temperature
are also shown (the lower curve, with units on the left). Note that it parallels the CO2
level curve very well.

18. Is the Temperature Really Changing ?
Yes! As everyone has heard from the media, recent years have consistently been
the warmest in hundreds and possibly thousands of years. But that might be a
temporary fluctuation, right? To see that it probably isn't, the next graph shows
the average temperature in the Northern Hemisphere as determined from many
sources, carefully combined, such as tree rings, corals, human records, etc.

19. How do we know if the temperature increase is caused by
anthropogenic emissions?
Computer models strongly suggest that this is the case. The following graphs show that 1) If only natural
fluctuations are included in the models (such as the slight increase in solar output that occurred in the first
half of the 20th century), then the large warming in the 20th century is not reproduced. 2) If only
anthropogenic carbon emissions are included, then the large warming is reproduced, but some of the
variations, such as the cooling period in the 1950s, is not reproduced (this cooling trend was thought to be
caused by sulfur dioxide emissions from dirty power plants). 3) When both natural and anthropogenic
emissions of all types are included, then the temperature evolution of the 20th century is well reproduced.