Relevance:
According to a new U.N. report, earth’s protective ozone layer is slowly but noticeably healing at a pace that would fully mend the hole over Antarctica in about 43 years.
About the Report:
- Report Title – Scientific Assessment of Ozone Depletion: 2022
- Prepared by – WMO, UNEP, National Oceanic and Atmospheric Administration (NOAA), NASA and European Commission.
- It is published every 4 years on Montreal Protocol (MP) progress.
- It confirms phase-out of nearly 99 percent of banned ozone-depleting substances (ODS) such as chlorine, bromine, methyl chloroform etc.
Key observations:
- Actions taken under MP contribute to ozone recovery in upper stratospheric layer.
- If current policies remain in place, ozone layer is expected to recover to 1980 values by around 2066 over Antarctic, by 2045 over Arctic and by 2040 for rest of world.
- Compliance with 2016 Kigali Amendment to MP, which requires phase down of production and consumption of some hydrofluorocarbons (HFCs), is estimated to avoid 0.3–0.5°C of warming by 2100.
- Stratospheric Aerosol Injection (SAI): Potential effects on ozone of the intentional addition of aerosols into the stratosphere.
Key Facts:
- Ozone – Highly reactive molecule formed of three oxygen atoms.
- Nearly 90% of Earth’s ozone resides in stratosphere (known as Ozone Layer) above troposphere (layer closest to Earth’s surface).
- Ozone Depletion –
- When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules.
- One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere.
- Health effects – Skin Cancer, Cataract etc.
Initiatives:
- 1985 Vienna Convention for the Protection of the Ozone Layer.
- Montreal Protocol on Substances that Deplete Ozone Layer, 1987 was negotiated as a protocol to Vienna Convention, 1985.
- Kigali Amendment – Parties to the Montreal Protocol agreed to phase down production and consumption of Hydrofluorocarbons.
Which one of the following is associated with the issue of control and phasing out of the use of ozone depleting substances? (2015)
a). Bretton Woods Conference
b). Montreal Protocol
c). Kyoto Protocol
d). Nagoya Protocol
Reference: Down to Earth
