1. Ozone layer
The ozone layer is a natural barrier between the earth and the sun's harmful ultraviolet rays. When the ozone layer depletes, these rays have greater access to the earth's surface. These rays cause skin cancer, cataracts, and damage to crops. The ozone layer is naturally depleted over time due to chemical reactions in the atmosphere. There are many factors that contribute to the depletion of the ozone layer including human activity.
2. CFCs
CFCs (chlorofluorocarbons) are man-made chemicals that destroy the ozone layer. In the 1980s, scientists discovered that CFCs were destroying the ozone layer. Since then, CFCs have been banned in many countries around the world.
3. Nuclear weapons testing
Nuclear weapons testing releases radioactive materials into the air. These radioactive particles travel high into the stratosphere where they affect the ozone layer.
4. Hydrofluorocarbons
Hydrofluorocarbons are man-made compounds that destroy the ozone layer and are released into the air during nuclear weapon tests.
5. Methane
Methane is a greenhouse gas that contributes to global warming. Methane is produced by animals and humans. Livestock produce methane while people release methane through their flatulence, belching, and burping.
6. Carbon dioxide
Carbon dioxide is a greenhouse gas that traps heat near the earth's surface. Plants use carbon dioxide to create food. Humans emit carbon dioxide through burning fossil fuels and deforestation.
7. Volcanoes
Volcanoes emit sulfur dioxide, which destroys the ozone layer. Sulfur dioxide is created when volcanoes erupt.
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