Third Example Informative Outline/Brief
Introduction: (Movie clip from Austin Powers) Background: Dr.Evil has
been cyrogenically frozen in space for thirty years, but has now returned to
earth. It is 1996 and a lot has happened since the last time the evil doctor
was on earth. Here is his plot for his next crime:
(Dr. Evil proposes the creation of an ozone hole to terrify the planet,
as the rest of the evil-doers of the world essentially say to him, "Been
there. Done that.")
Ironically, the worst thing Dr. Evil could think of to do was something
that has already happened, but we don't give it a second thought. We have all
heard of the ozone hole, but it hard to be concerned about something we can't
see. None of us are scared to open our refrigerators or enter our cars because
we're worried about the ozone depleting substances that we might release into
the atmosphere.
Central Idea: Ozone depletion remains a real problem for several reasons.
Preview: First of all, ozone levels have dropped significantly in the
past few years. Secondly, humans continue to use ozone-depleting substances in
enormous quantities. Finally, the drop in the ozone has resulted in serious
consequences in many of earth's ecosystems.
Trans: Ozone, a molecule containing three oxygen atoms, is found mostly
in the part of our atmosphere called the stratosphere, which is 10-50 km above
the surface of the earth. The bluish pungent gas protects the earth from the
sun's radiation by absorbing the most damaging waves.
I. However, ozone depletion is still occurring today at alarming rates
adding to the severity of this environmental problem.
A. There has been a significant decrease in
ozone over every continent in the world, especially North America,
i. The ozone above the
ii. Other country's ozone levels have decreased
anywhere from 3-20%, as shown by the graph from NASA space satelites. (6)
B. Ozone depletion is greatest over
i. The ozone hole is not an actual hole in the
stratosphere, but an area with extremely low levels of ozone.
ii. Ozone levels fall by up to 70% according to
chemists specializing in Arctic weather (3) .
iii. The hole is now about 83 million square
miles, which is large enough to cover all of
Trans. The problem of downward trends in ozone level is due to people's
wide use of ozone depleting substances.
II. Human activity is responsible for 85% of today's ozone depletion (9).
A. Our use of Chlorofluorocarbons (CFC's) is
the main source of ozone depletion.
i. Because they are stable, non-volatile,
inexpensive, and nontoxic, CFC's were widely used as refrigerants, in air
conditioners, for cleaning electronic circuit boards, and in foam padding.
ii. In 1986, the world produced 1.13 metric
tons of CFC's. IBM's San Jose manufacturing facility , the largest industrial
emitter of CFC's, alone used 1.5 million pounds of CFC's for cleaning purposes.
(11)
iii. This graph shows the increase of CFC's
used in the
B. The same reasons that make CFC's so ideal
for human use is also what makes them so deadly to the environment.
i. CFC's don't react with rain or other
molecules due to their stability, so they penetrate through the troposhere, the
lowest level of atmosphere, and into the ozone-rich stratosphere.
ii. Here the strong ultraviolet radiation is
powerful enough to break the stable molecule, releasing chlorine atoms.
Chlorine atoms catalytically deplenish ozone, as one chlorine atom can destroy
over 100,000 ozone molecules. (9)
Transition: The problem of ozone depletion allows more ultraviolet light
to reach the earth. The World Meterological Organization and Network for
Detection of Stratospheric Change has measured an increase of 5% of UV-A rays
and a 10% increase in UV-B rays since the 1980's. (8)
III. This excess ultraviolet light is detrimental to all lifeforms on
earth because it has the ability to ionize and bump electrons out of atoms and
molecules resulting in tissue damage and DNA mutations in living organisms.
A. Plants are especially sensitive to UV rays.
i. Macroalgae and seagrasses are major biomass
producers and provide food for many organisms. Excess UV rays inhibits the
growth of these important species. (8)
ii. On, land UV rays have resulted in crop
damage, a potential threat to our food production.
B. Animals are also harmed by the increase in
UV radiation.
i. There has been a measured 6-12% decrease in
the populations of phytoplankton in the Arctic areas, where animals aren't used
to much ultraviolet light. These small animals play a very important role in
the food chain, and their lowered populations could lead to serious
repercussions for larger fish. (8)
C. Humans too experience the negative effects
of increased ultraviolet radiation.
i. UV rays are responsible for causing eye
damage and cataracts in humans.
ii. UV rays also cause a decrease in immunity
in humans.
iii. UV rays result in skin cancer, the most
prevalent form of cancer in the country according to the American Cancer
Society. (1)
a. One out of 7 Americans develop skin cancer,
and of the 600,000 cases of skin cancer detected every year, 8,200 of them
result in death. (1)
b. The United Nations Environmental Programme
estimates that if the ozone level drops another 10%, there will be 360,000
additional cases of skin cancer around the world each year. (8)
Conclusion: As you can see, ozone depletion continues to be a major
problem today. The rising ozone depletion rates, our continual use of ozone
depleting substances, and the increase in solar radiation prove that the ozone
level is an important area of environmental concern, even though we take it so
lightly. Maybe now some of you care a little more about the problem of ozone
depletion. Maybe for others it will take something more drastic, such as a
relative developing skin cancer, in order for you to regard ozone depletion as
a real problem. However, I hope we all start caring soon, before our fate is
worse than even Dr. Evil could have imagined.
Bibliography:
1.) American Society for Dermatologic Surgery.
2.) "Book of the Year (1997): The Environment" Britannica
Online. http://www.eb.com.180/cgi-bin/g?DocF=bog(p7/K02835.html.
3.)Brown, Theodore L., J. Eugene LeMay, Jr., and Bruce E. Bursten.
Chemistry: The Central Science. Seventh Edition. Prentice Hall:
4.)"Electromagnetic Radiation: Forms of Electromagnetic Radiation:
Ultraviolet Radiation." Britannica Online.
http://www.eb.com.180/cgi-bin/g?DocF=macro/5002/7/17.html.
5.) International Cooperative for Environmental Leadership.
http://www.icel.org/index.html.
6.)NOAA Aeronomy Laboratory. http://www.al.noaa.gov?#Home.
7.) Thompson, Stephen.
8.)United Nations Environment Programme..
http://sedac.ciesin.org/ozone/docs/UNEPsummary96.html.
9.)United States Environmental Protection Agency.
http://www.epa.gov/docs/ozone/index.html.
10.) Zurer, Pamela S. "
11.)Zurer, Pamela S. "Looming Ban on Production of CFCs, Halons
Spurs Switch to Substitutes." Chemical &Engineering News.