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UPSC Prelims 2019 · Environment · Warming World
Which of the following statements are correct about the deposits of ‘methane hydrate’?
- Global warming might trigger the release of methane gas from these deposits.
- Large deposits of ‘methane hydrate’ are found in Arctic Tundra and under the seafloor.
- Methane in atmosphere oxidizes to carbon dioxide after a decade or two.
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Show the answer and explanation
Answer: (d) 1, 2 and 3
Where hydrates sit, how warming releases them, and what methane becomes in the air — all three are right.
Statement by statement
1. ✓ CORRECT — a feedback loop Methane hydrate is methane trapped in a cage of ice, stable only when it is cold and under pressure. Warm the permafrost or the sea floor and the cage breaks, releasing methane that causes more warming.
2. ✓ CORRECT They lie under Arctic permafrost and in the sediments of continental margins, including India’s Krishna–Godavari basin, where India’s gas-hydrate expeditions (NGHP) found them.
3. ✓ CORRECT — about 12 years Methane lasts about 12 years in the air before hydroxyl radicals (OH) turn it into CO₂ and water. It is short-lived, but about 80 times stronger than CO₂ over 20 years.
The idea
Methane hydrate looks like ice but burns: each lump is methane gas locked inside a cage of frozen water. The cage holds only where it is very cold and under high pressure. That is why it is found in two places only: under Arctic permafrost and in deep-sea sediments.
Planet warms → Permafrost thaws and sea floor warms → The ice cage breaks → Methane escapes → More warming → More hydrate breaks down
Why the others are wrong
(a) Misses statement 3. Methane does oxidise to CO₂ within about a decade.
(b) Misses statement 1, the warming feedback, which is the main worry.
(c) Misses statement 2. Tundra and seafloor are exactly where hydrates are found.
The trap
Statement 3 feels wrong because we think methane “stays”. It doesn’t: it is short-lived, which is exactly why cutting methane cools the planet faster than cutting CO₂.
Also know
The Global Methane Pledge (COP26, 2021) aims to cut methane 30% below 2020 levels by 2030. India has not signed it.
🔒 Methane hydrate = methane in an ice cage · permafrost + seafloor (KG basin) · warming releases it · CH₄ → CO₂ in ~12 years.