Global Effects of Ozone Depletion
Background Information
The information given here is purposely vague, there is just enough to get you
oriented to the topic.
Approximately
25 kilometres above the Earth's surface, there lies a thick blanket of ozone (O3),
the ozone shield, which protects life on our planet. This layer absorbs most of
the Sun's damaging ultraviolet (UV) rays. UV can cause serious damage to living
tissue and affects the health of organisms in a wide variety of ways.
The
thickness of the ozone layer varies naturally. Stratospheric pressures and
winds tend to move the ozone towards the poles; therefore, the layer may be 50%
thicker at the mid to high latitudes. As well, due to the lack of light at the
northern polar region in winter (opposite in the southern hemisphere), the
thickness of the ozone layer is at its greatest by February.
In the
late 1960s, it was suspected that emissions from aircrafts may have been
contributing to the depletion in the ozone layer. Scientists, in the early
1970s, believed that it was, in fact, active chlorine atoms that were
destroying the ozone. After the discovery of the hole in the ozone layer over
Antarctica in 1985 and more evidence surfacing regarding the effects of
synthetic compounds, a concerted effort was put forth on a global scale to
tackle the issue of ozone depletion.
Emissions
of industrial halocarbons account for most of the ozone depletion in the
stratosphere. Some of these compounds have been around since the 1930s and are
still widely used in diverse applications. As an example, one single Styrofoam
cup has one billion (109) ozone-destroying molecules trapped within
its airspaces, meaning that it has the potential
of destroying one hundred thousand billion (1014) ozone molecules.
To compound the problem, these stable, ozone-depleting chemicals can survive in
the atmosphere from ten to hundreds of years.
The ozone
shield has thinned dramatically in the northern polar region as well. Many
scientists believe that an Arctic hole in the ozone will soon be a reality.
Ozone losses are not confined to the polar regions either. The 1980s saw triple
the losses in ozone, as compared to the 1970s, across temperate and tropical
zones of the world.
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Guiding Questions
This research topic should be presented as a formal paper. Give as full
an account of the environmental issue as you can. Be sure to also include
detailed answers to each of the following guiding questions within your paper.
Include maps, tables, charts and diagrams as required. Remember to cite all
sources used throughout your work.
1. Is there a difference between
ground-level ozone and stratospheric ozone?
2. What are the specific names of
the ozone-depleting substances (ODSs) in question, and what are they used for
throughout the world?
3. How exactly do ODSs destroy
stratospheric ozone?
4. What ecological concepts must we
know to understand the problem?
5. What abiotic and biotic factors
are involved in this issue?
6. Are there natural occurrences in
the ecosystem that also contribute to ozone depletion?
7. What is the scientific evidence
that this is indeed an environmental problem needing to be addressed?
8. What exactly is UV radiation? Are
there differences in type of UV radiation? Do they have different effects?
9. How is the natural world (not
including humans) affected by ozone depletion and increased UV radiation, plants, animals and various
ecosystems?
10. Why is it that the Antarctic
region is much more adversely affected by ozone depletion than other areas?
11. How has the Antarctic ozone hole
changed since 1985?
12. Are other areas at risk of ozone
depletion as well?
13. How are humans affected by ozone
depletion and increased UV radiation, directly and indirectly?
14. How is ozone depletion linked to
the global climate?
15. Who are the main culprits
responsible for this environmental issue?
16. Who does this issue affect?
17. What are the social/cultural
effects of this problem?
18. Who is involved in coming up with
solutions to the problem?
19. What can an individual do to help
counteract the problem of ozone depletion?
20. What is being done to address the
problem on national and international levels (scientific problem-solving and
legislation, e.g. Montreal Protocol, US Clean Air Act)?
21. Which of the available strategies
do ecologists consider to be most effective for controlling ozone depletion?
22. What does the future hold for the
success and/or failure of these solutions?
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