Which major gas is responsible for Ozone Depletion?
VerifiedAnswer: CFC
Explanation:
Chlorofluorocarbons (CFCs) are the primary culprits behind ozone layer depletion. These synthetic compounds were widely used in refrigerators, air conditioners, aerosol sprays, and foam-blowing agents throughout the 20th century due to their excellent chemical stability and non-toxic properties.
The ozone layer, located in the stratosphere about 15-50 kilometers above Earth's surface, acts as our planet's natural sunscreen. It absorbs harmful ultraviolet (UV) radiation from the sun, protecting all life forms on Earth. However, when CFCs reach the stratosphere, they undergo a dangerous transformation that threatens this protective shield.
Here's how CFCs destroy ozone molecules: When CFCs rise to the stratosphere, they encounter intense UV radiation that breaks them apart, releasing chlorine atoms. These chlorine atoms are extremely reactive and attack ozone (O₃) molecules, breaking them down into oxygen (O₂) molecules. The most concerning aspect is that one chlorine atom can destroy thousands of ozone molecules before it becomes inactive, making CFCs incredibly destructive despite their relatively small concentrations.
The discovery of ozone depletion, particularly the formation of the ozone hole over Antarctica, led to urgent international action. Scientists found that this depletion was primarily caused by human-made chemicals, with CFCs being the major contributor. The evidence was so compelling that it resulted in the Montreal Protocol in 1987, an international treaty designed to phase out ozone-depleting substances.
Common CFCs that have contributed to ozone depletion include CFC-11 (used in foam blowing and as solvents), CFC-12 (used in refrigeration), and CFC-113 (used in electronics cleaning). These compounds have extremely long atmospheric lifetimes, ranging from 50 to over 100 years, which means that even after their production was banned, they continue to affect the ozone layer for decades.
Thanks to global efforts to reduce CFC emissions and replace them with ozone-friendly alternatives, the ozone layer is slowly recovering. However, complete recovery is not expected until the middle of this century due to the persistent nature of these chemicals in the atmosphere. This scientific success story demonstrates how understanding the environmental impact of human activities can lead to effective solutions when the global community works together.
