Context:
Recent eruption of the Hunga Tonga-Hunga Ha’apai volcano made an impact on the ozone layer.
Hunga Tonga-Hunga Ha’apai:
- A submarine volcano in the Tongan archipelago
- Location – Southern Pacific Ocean
- Formation – Result of subduction of the Pacific Plate beneath the Indo-Australian Plate
How volcanic eruptions impact ozone layer?
- Eruption triggers massive stratospheric water vapor plume, potentially enhancing early- season Antarctic ozone-depletion reactions.
- Volcanic eruptions inject large quantities of sulphur dioxide into the stratosphere facilitating the chemical conversion of chlorine into more reactive forms that destroy ozone.
- Volcanoes significantly contribute atmospheric bromine, and hydrogen chloride, a common volcanic gas that efficiently destroys ozone.
- Particles generated by volcanic eruptions provide surfaces for chemical reactions, for ozone-depleting substances.
An eruption from a volcano can result in approximately 1-5% of damage to the atmospheric ozone. For instance, the 1991 eruption of Mt. Pinatubo in the Philippines resulted in substantial ozone depletion within the stratosphere.
Ozone hole:
- Ozone hole refers to regions in the stratosphere over Antarctica where the Ozone (O3) layer significantly depletes during the Southern Hemisphere’s spring season.
- It denotes areas where ozone levels drop below 220 Dobson Units.
- Average thickness of the ozone layer over Earth – about 300 Dobson Units.
- Ozone depletion is due to the chemical action of pollutants known as ozone-depleting substances (ODS).
- Major ODS – chlorine, bromine, Chlorofluorocarbons, carbon tetrachloride, halons, etc.
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Source: India Today
Previous Year Question
Which one of the following is associated with the issue of control and phasing out of the use of ozone-depleting substances?
[UPSC Civil Services Exam – 2015 Prelims]
(a) Bretton Woods Conference
(b) Montreal Protocol
(c) Kyoto Protocol
(d) Nagoya Protocol
Answer: (b)
Explanation:
The Montreal Protocol provides a set of practical, actionable tasks to phase out ozone- depleting substances. Therefore, option (b) is the correct answer.
