A new study has reported for the first time significant reductions in atmospheric concentrations of potent ozone-depleting substances (ODS) known as hydrochlorofluorocarbons (HCFCs).
Ozone-depleting substances
- Ozone-depleting substances (ODS) are chemicals that cause the depletion of the ozone layer in the stratosphere.
- The ozone layer is essential for protecting life on Earth by absorbing most of the sun’s harmful ultraviolet (UV) radiation.
- The most common ODS include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, carbon tetrachloride, and methyl chloroform.
- These substances are commonly used in refrigerators, air conditioners, fire extinguishers, and aerosols.
Ozone layer
- The ozone layer is located between about 15 and 35 km (9 and 22 mi) above the Earth’s surface. It is the region of the upper atmosphere containing relatively high concentrations of ozone molecules (O3).
- The ozone layer was discovered in 1913 by French physicists Charles Fabry and Henri Buisson.
- About 90 percent of the atmosphere’s ozone is found in the stratosphere. It protects the Earth from the Sun’s harmful ultraviolet (UV) radiation.
- It is found in lower concentrations at ground level, called tropospheric ozone. This ozone acts as a pollutant that is a major part of the smog over cities.
Montreal Protocol
- The Montreal Protocol has contributed significantly to the decline in HCFC levels. This protocol was signed in 1987.
- This protocol is a global agreement to protect the stratospheric ozone layer by eliminating the production and consumption of ODS such as chlorofluorocarbons.
- A worldwide ban on the production of CFCs has been in place since 2010 under this protocol.
- HCFCs have been produced to replace CFCs. However, it is also a strong greenhouse gas and ODS.
- Therefore, the Copenhagen (1992) and Beijing (1999) amendments to the Montreal Protocol mandated the phase-out of HCFC production and use by 2040.
Kigali Amendment to the Montreal Protocol
- In 2016, the Parties to the Montreal Protocol adopted the Kigali Amendment.
- It aims to phase-out the production and consumption of hydrofluorocarbons (HFCs) globally.
HFCs are widely used as an alternative to ODS such as hydrochlorofluorocarbons (HCFCs) and chlorofluorocarbons (CFCs), which are already regulated under the