Understanding & Tracking
Antarctica’s Ozone Hole
Based on material from ecohealth101.org & ozonewatch.gsfc.nasa.gov
Ozone is…
Ozone is a form of oxygen with 3 oxygen atoms (O3).
The oxygen we breath
has 2 atoms of oxygen
(O2).
Ozone is…
• Ozone is highly
corrosive and toxic
and is used as a
disinfectant.
• It can be found in
small concentrations in
the troposphere where
it is considered a
pollutant.
Ozone is…
It is thinnest
around the
equator and
denser at the
poles.
Dobson Units
• Ozone levels are
reported in Dobson
Units (DU).
• 300 DU is an
average value.
Ozone…
• Ozone is very highly reactive and
will combine with other
substances easily.
• Near the earth's surface, these
reactions cause rubber to crack
and damage people's lung
tissues.
• Inhaling ozone can damage the
respiratory tract, which enables
us to breathe.
Ozone…
Ozone also
stunts plant
growth. That
hurts farmers,
agriculture,
and our
economy.
What is the ozone layer?
Most of the planet’s
ozone hangs out in
the Stratosphere,
the layer above the
Troposphere.
What is the ozone layer?
• Ozone in the stratosphere protects people,
animals, and plants from harmful ultraviolet rays.
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Watch closely!
What’s Eating the Ozone?
• Scientists in the
1960s realized
that something
was going wrong
in the ozone layer.
• They soon figured
out that human
actions were
damaging Earth's
shield against
harmful radiation.
What is the Ozone Hole?
The ozone hole is not
technically a “hole” where no
ozone is present, but is actually a
region of depleted ozone in
the stratosphere over the Antarctic
that happens at the beginning of
Southern Hemisphere spring
(August-October).
The average concentration of
ozone in the atmosphere is about
300 Dobson Units; any area
where the concentration drops
below 220 Dobson Units is
considered part of the ozone hole.
Who discovered the Ozone Hole?
The Antarctic Ozone Hole
was discovered in 1985 by
British scientists Joseph
Farman, Brian Gardiner,
and Jonathan Shanklin of
the British Antarctic
Survey.
The Ozone Hole has
steadily grown in size (up
to 27 million sq. km.) and
length of existence (from
August through early
December) over the past
two decades.
What causes Ozone Depletion?
•
The Ozone Hole is caused by chemicals called
CFCs, short for chlorofluorocarbons. CFCs
escape into the atmosphere from refrigeration
and propellant devices and processes, and they
are so stable they last for decades. This long life
allows some CFCs to eventually reach the
stratosphere.
•
The chemicals that make up CFCs, mainly
chlorine and fluorine, float around the
stratosphere, breaking up ozone molecules.
•
One molecule of CFC can destroy more than
100,000 molecules of stratospheric ozone.
•
Today, no spray cans contain CFCs. Other
chemicals are gradually replacing the CFCs in
air conditioners.
Ultraviolet Radiation
The depletion of the ozone
layer leads to higher levels of
ultraviolet radiation
reaching Earth's surface.
This in turn can lead to a
greater incidence of skin
cancer, cataracts, and
impaired immune systems,
and is expected also to
reduce crop yields, diminish
the productivity of the oceans,
and possibly to contribute to
the decline of amphibians that
is occurring around the world.
What is the Montreal Protocol?
•
The Montreal Protocol is a landmark international
agreement designed to protect the stratospheric
ozone layer.
•
The Montreal Protocol says that the production and
consumption of compounds that deplete ozone in the
stratosphere--chlorofluorocarbons (CFCs), halons,
carbon tetrachloride, and methyl chloroform--are
to be phased out by 2030.
The Future of the Ozone Hole
•
As a result of the Montreal
Protocol, atmospheric
concentrations of some ozonedepleting substances, such as
CFC-11, have begun to decline
and concentrations of others will
follow suit over the next decade.
• Over the much longer term, the
health of the ozone layer will
depend primarily on our ability to
rid the atmosphere of present
ozone-depleting substances and
prevent the release of new ones.
Mapping the Ozone Hole
• On your Ozone
Hole Activity page,
copy the Ozone
Hole on each of
the provided maps
using a light blue
pencil.
The Ozone Hole in October, 1980
The Ozone Hole in October, 1985
The Ozone Hole in October, 1990
The Ozone Hole in October, 1996
The Ozone Hole in October, 2000
The Ozone Hole in October, 2005
What do you think the Ozone Hole
will look like in the near future?
• In the Summary Questions, predict the
future for the years 2010 and 2050 by
coloring with your light blue pencil what you
THINK the Ozone Hole will look like.
The End
Bonus: Explain
the humor.
Is it funny?
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