Relevance: GS-3 (Environment – Atmospheric Chemistry) • Source: The Hindu, NASA, NOAA
NASA and the National Oceanic and Atmospheric Administration announced that the 2025 Antarctic ozone hole was the fifth smallest since 1992, indicating continued global progress after the Montreal Protocol. The average size peaked at levels significantly smaller than the 2000s’ long-term average.
2. What is the Ozone Layer and Ozone Hole?
- The ozone layer is a high-concentration band of ozone (O₃) in the stratosphere, absorbing harmful ultraviolet-B radiation.
- An ozone hole is the seasonal thinning of this layer over Antarctica, mainly caused by chlorofluorocarbons (CFCs) and other ozone-depleting substances reacting on polar stratospheric clouds.
- Peak depletion occurs during the Southern Hemisphere spring (August–October).
3. Concerns and Way Ahead
| Concerns | Way Ahead |
|---|---|
| Persistent variability | Enforce Montreal Protocol & Kigali Amendment |
| Emerging chemicals | Strengthen satellite monitoring (Aura, Sentinel) |
| Climate link | Promote safe refrigerant alternatives |
| — | Align actions with SDG 13 & SDG 3 |
UPSC Prelims Practice Question
Q. The thinning of the ozone layer over Antarctica is primarily due to:
(a) Increase in carbon dioxide
(b) Reactions of CFC-derived chlorine on polar stratospheric clouds
(c) Global warming
(d) Methane emissions
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