The poisoning of the Earths ozone layer is increasingly attracting worldwide
concern for the global environment and the health effects of life on the Planet
Earth. There is not just one particular cause for the ozones depletion; the
accumulation of different pollutants into our ozone layer has all added up and
equaled a worldwide problem. There is not just one effect from the poisoning of
the ozone, but instead multiple ramifications from diseases to death. The damage
to the ozone is increasing with every second; moreover, there are many ways we
can help reduce the problem and preserve the ozone layer. Ozone is a pale blue
gaseous form of oxygen, in chemical form it is also known as O3.
Ozone can be
beneficial or harmful depending on its location in the Earths atmosphere. If
the ozone is located in the troposphere (which extends from the surface of the
Earth up to approxiametly10 miles) it is a harmful pollutant and a major
component in smog and other environmental health problems. Such tropospheric
ozone can damage plastic, rubber, plant and animal tissue. Ozone located
approximately 10-25 miles above the Earths surface, in a part of the
Earths atmosphere called the stratosphere is very beneficial. The ozone is a
major factor that makes life possible on Earth. About 90% of the planets
ozone is in the ozone layer.
Ozone in this layer shields and filters out the
Earth from 95-99 percent the suns ultraviolet radiation. A low level of ozone
does not protect or prevent the suns ultraviolet rays from reaching the
surface of the Earth, therefore, overexposing life on Earth causing many
diseases. The depletion of the ozone is caused by many factors, but the one
cause that will be elaborated on in the next paragraph is the main reason our
ozone is continuously being poisoned. The major cause in the depletion of the
Earths ozone layer is because of the release of chlorofluorocarbons into the
atmosphere. Chlorofluorocarbons also known as CFCs, are industrially produced
chemical compounds that contain the elements chlorine, fluorine, carbon, and
sometimes hydrogen that will break down the protective ozone in the atmosphere.
Since CFCs are heavier than air, the process of CFCs reaching the ozone will
generally take from two to five years to get into the stratosphere. When CFCs
reach the stratosphere, the suns ultraviolet radiation cause them to break
apart. Therefore, the chlorine atoms inside the CFCs are released and will react
with ozone, starting a chemical destruction cycle of ozone. To show the extent
of destruction chlorine can produce, one chlorine atom can break apart more than
100,000 molecules of ozone. Chlorofluorocarbons are not naturally produced
chemical, but shockingly are all man-made products.
CFCs products and other
ozone depleting substance are everywhere and come in all forms such as: aerosol
spray cans, industrial cleaning agents, insulators, Styrofoams, coolants,
auto air conditioners, home air conditioners and refrigerators (see next the pie
chart on next page for more information). Majority of CFCs contributing to
depletion is the auto air conditioners in our cars. The CFCs inside auto and
home air conditioning systems, as well as in refrigerators can leak out, and
eventually will rise into the atmosphere destroying the ozone layer. According
to Greenpeace, The manufactures of CFCs and other ozone depleting products
include: Dupont, Elf-Atochem, ICI, LaRouche, Rhone Poulenc, Nippon Halon, and
Allied Signal (Greenpeace).
The total value of all the ozone depleting
products since 1986 exceeded $30.6 billion, with the United States producing a
large majority of the products. There are other elements and man-made chemicals
that contribute to the ozone depletion. Any form of elemental bromine that
reacts with ozone is very violotile.
For examaple, methyl bromide is a compound
that is used as a pesticide and fumigant; the break down of bromine atoms in
pesticides due to the suns rays, can be more than 40 times as destructive to
ozone molecules than chlorine atoms. Halons which are used in fire extinguishers
contain bromine and are also depleters of the ozone. Another product that is
destructive is methyl chlorofoam, in which are solvents in industrial processes.Hydrochlorofluorocarbons are known as HCFCs, they are categorized as class II
ozone depleting substances because these products do not deplete the ozone as
much as CFCs. HFCs are currently being used as replacements for CFCs, even
though they deplete the ozone to some extent.
Man-made chemicals are not the
only way ozone depletion can occur; natural depletion is also a reason the ozone
layer is thinning. Natural depletion is another reason why ozone depletion takes
place. Ultraviolet light in the atmosphere breaks down the ozone molecules into
molecular oxygen and atomic oxygen, in a process called photolysis. Natural
hydrogen oxides account for nearly 11% of all natural depletions. Nitrogen
oxides are responsible for 50-70% of all natural depletions.
Volcanoes and
oceans naturally emit large amounts of chlorine, but they easily dissolve in
water and are washed out by rain, therefore, the chlorine does not reach the
stratosphere to deplete the ozone. Natural depletors are factors we really do
not have much control over; however, we do have control over the man-made
chemicals. The thinning of the ozone layer that protects us from ultraviolet
radiation is increasing and ramifications will have numerous worldwide effects
on human life. Statistics and laboratory experimental studies have proven the
increase exposure to ultraviolet rays can cause actinic keratoses, melanoma and
nonmelanoma cancers. Excessive or even mild exposure to ultraviolet radiation
can also cause eye diseases such as: cataracts (loss of focus in the lens which
clouds vision), pterygium (tissue growth on the white of the eye that can block
vision), skin cancers around the eyes, blindness, and degeneration of the
macula. According to the Envionment Protection Agency, It is estimated that a
sustained 10 percent loss of ozone could lead to a 26 percent increase in the
number of cases of nonmelanoma skin cancer per year worlwide and At the
same time, 1.
6 million additional cataract cases per year could occur (Envionment
Protection Agency). The increase of ultraviolet radiation because of the
reduction of ozone will also immune systlem suppression. Scientist have found
that overexposure to the sun can alter the function and distribution of white
blood cells (disease- fighting cells) in humans, resulting in a weaker immune
system to fight diseases and a worldwide increase in sickness. Ultraviolet
radiation also attacks DNA in individual cells, this process destroys the basic
building blocks of life. The depletion of the ozone layer will just as
dramatically effect plants as much as it would the humans. In plants and trees
the increase in ultraviolet radiation will interfere with photosynthetic
activity, metabolism, flowering, life cycles and growth.
The ultraviolet
radiation could get so high that it may start burning trees and eventually
forrests, in the process destroying our sources of oxygen that we need to
survive. The increase in radiation will start to diminish crops and other food
sources. Starting with the depletion of the ozone layer, the domino effect of
the extinction of biological systems on Earth would continue to plants and then
on to the marine ecosystem. The effects of poisoning of the ozone layer will
lash out on the marine ecosystem. The marine ecosystem would severely suffer
from the thinning ozone and the increase exposure to ultrviolet radiation.
Starting with phytoplankton, the foundation of acquatic food chains, would loose
their mobility, reproduction ability, a decrease in photosythetic activity and
orientation in these small organisms. Scientific proof has demonstrated a direct
reduction in phytoplankton production due to ozone depletion-related increases
in ultraviolet radiation. Damage to the early developmental stages of shrimp,
fish, crabs, amphibians and other animals has also been linked to ultraviolet
radiation exposure. Greenpeace said, a sustained 16% ozone depletion could
lead to a loss of up to 7 million tons of fish per year.
Furthermore, the
population of all other animals would be in danger because of the diminishing
supply of smaller acquatic creatures. Animals, the most innocent victims of the
ozone depletion will have to pay for their lives first. With exposure to
ultraviolet radiation animals will eventually develop tumors similar disease to
humans, such as: eye tumors, to burning skin,changes in pigmentation, skin
cancers, and eventual suppression of the immune system. Domestic animals may
experience loss of hair, cancers, light skin and eye diseases. Skin and eyes
tumors exclusively in cows, goats, sheeps, horses, dogs, and cats. Through the
direct effect of exposure to ultraviolet radiation and the indirect effects on
the limited food species further down the chain, most animals if not all would
be doomed.
The retention our ozone is so important that every life form on Earth
depends upon the protection of the ozone layer, against the suns harmful
emmision of radiation. During the late 1970s, scientist discovered a
hole in the ozone over the skies of Antartica. The holes in the
ozone in Antartica has increased since and only appears in the seasonal
springtime. According to Greenpeace, Measurements of ultraviolet rays in
Antarctica in 1993 were 50% higher than in 1991 and 1992 (Greenpeace). Recent
surveys of the ozone layer in Antarctica, have been reported in the annual
spring-time up to a 90% decrease in ozone.
In Antarctica a decrease in
stratospheric temperature is a coincidence, with the general increase in the
lower atmospheric temperatures. Some speculate this is because of the reduced
ozone above Antarctica and the carbon dioxide warming in the troposphere.Antarctica is not the only place in the world with holes in the ozone, Canada
and the Artic also have their own ozone depletion worries. The Arctic and parts
of Canadas ozone levels have increasingly dropped.
According to the
Environmental Protection Agency, one-third of the Northern Hemisphere is
depleted; ozone levels over the Arctic are at an all-time low of up to 45%
depletion from Greenland to Scandnavia to Western Siberia. Over the last 30
years, temperatures have been studied and determind that a 0.5 Celsius degree
increase had taken place per decade. The Arctic as a result. has experienced
melting ice packs, a weaker cooling trend, and a decline in actual ice area.Parts of Canada has also experienced a drop in ozone levels by 15%.
Scientists
feel through the years 1998-2000 to be the most vulnerable period when
accumalated atmospheric chlorine and bromine levels from human made elements
will be at its peak. One of the first major steps in trying to stop the ozone
depletion took place in September of 1987, negotiators from around the world met
in Montreal to sign a treaty that limits the use of CFCs and halons. Soon after
the minds of science gathered in Montreal, the Montreal Protocol was signed so
that in developed countries the production and consumption of CFCs would be
diminished by the year 2000. The Clean Air Act Amendments of 1990 was amended to
control ozone depleting chemicals in the United States. This Clean Air Act
created an excise tax on all CFC products, that would increase year to year and
gradually phase out the production of CFCs.
The use of CFCs are currently banned
in the United States. In December of 1995 over 100 nations agreed to phase
developed countries production of the pesticide methyl bromide, predicted to
cause about 15% of ozone depletion by the year 2000. The production of CFCs in
developing countries will have ceased by the year 2010 (Greenpeace). Just a
couple years ago on December 16, 1997 the Antarctica Protocol was finally
ratified after six years of lobbying.
The Antartica Protocol bans mining for a
minimum of 50 years and designates the whole continent and its marine ecosystem
as a natural reserve devoted to peace and science (Greenpeace). There are
many ways individuals can slow the rate of ozone depletion, through careful
product purchasing of appliances that do use ozone depleting substances.Immediately repair any leaks in your refrigerator and make sure all CFCs are
recoverd and properly recycled before any refrigerator is scrapped. Avoid buying
all products that contain Ozone depleting substances such as: carbon
tetrachlorides in dry-cleaning agents, halons found in fire extinguishers,
methyl chlorofoam in degreasers and propellants, and anything insulated in
styrofoam.
Consider alternatives to air conditioning systems in your houses,
such as: insulating your homes, install fan cooling systems, apply coats of
reflective seal on your roof to keep heat out, and vents hot attic spaces to get
hot air out of your homes. Be sure maintainance your cars air conditioning
systems so that no freon leaks. In conclusion, the protection and conservation
of our ozone is vital for the continuation of all biological systems and life
forms on earth. Even with all the laws and CFC bans, we must all contribute a
little something to nurse our fragile ozone layer back to health. If we decide
to let things go on the way they are, extinction will start with the marine
ecosystems, then the plants will start to die out, the animals will starve or
die of diseases and eventually we will fall right in line as the final domino
falls.
Bibliography
Firor, John.
The Changing Atmosphere A Global Challenge. New Haven: Yale
University Press, 1990. 26-43. Stoker, Stephen. Ozone. Vol.
14. 14ed.Chicago: Fetzer, 1996. 894. Environmental Protection Agency.
Ozone
Depletion. Internet Online. December 24, 1997. http://www.epa.
gov/ozone/science/effects.html
. Greenpeace. Ozone Depletion.
Internet Online. date accessed: July 24,
1999. http://www.greenpeace.
org . Microsoft Encarta Encyclopedia 98.Ozone. Computer program.
1998ed. Microsoft Corporation.
Environment