Understanding Tracking Antarcticas Ozone Hole Based on material

Understanding & Tracking Antarctica’s Ozone Hole Based on material from ecohealth 101. org & ozonewatch. gsfc. nasa. gov

Ozone is… Ozone is a form of oxygen with 3 oxygen atoms (O 3). The oxygen we breath has 2 atoms of oxygen (O 2).

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. Watch closely!

What’s Eating the Ozone? • Scientists in the 1960 s 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?