Ozone Depletion

The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. The ozone layer is about 25 kilometers above the ground.

The Sun emits (sends out) ultraviolet light. These ultraviolet rays can cause skin cancer and eye damage in humans. They can also damage plants.

The ozone layer protects organisms on the Earth from harmful ultraviolet radiation. Ozone absorbs ultraviolet rays from the Sun. The ozone layer reduces the quantity of ultraviolet radiation that reaches the ground.


The ‘hole’ in ozone layer

In 1985, scientist discovered that there was less ozone than there should be over the Antarctic, especially in the Antarctic spring. They called this the ozone hole.

The ozone hole is not really a hole. It is just an area where there is less ozone than normal.

Satellites, such as NASA’s Aurora satellite, measure how much ozone there is in the atmosphere. Each year, the ozone hole has been getting larger. It has also been lasting for longer in the year.

What causes the ozone hole?

Gases called CFCs (chloro-fluorocarbon) caused the problems with the ozone layer.

CFCs are man-made. They were invented in 1920s. They were used in air-conditioners, refrigerators and aerosol cans. No-one knew that they were harmful.

CFCs rise up high into the atmosphere. They react with ozone and break it down. This happens especially when it is cold, and when sunlight shine onto the CFCs and ozone.

CFCs last for a very long time. Scientist think that the CFCs in the atmosphere will stay there for about one hundred years.


Can ozone hole be recovered again?


 To repair the ozone layer, we must stop releasing ozone-depleting compounds into the atmosphere. 

Scientists hope that the ozone layer will return to normal within fifty years of completely stopping the release of these compounds.