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.

What’s Eating the Ozone?

• Scientists in the 1960s realized that something was going wrongin the ozone layer.

• They soon figured out that humanactions 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 Holewas 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 radiationreaching Earth's surface.

This in turn can lead to a

greater incidence of skincancer, 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 ozone-

depleting 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?