Detailed Explanation:

Answer: Option 4 — 1, 2 and 3

All three statements about methane hydrate deposits are correct. Methane hydrates are ice-like structures that trap methane and are vulnerable to release under warming conditions, creating a potential climate feedback loop.

✅ Statement 1 – Correct: Global warming can destabilize methane hydrate deposits in permafrost and ocean sediments, triggering methane release—a potent greenhouse gas that amplifies warming.
✅ Statement 2 – Correct: Large methane hydrate reserves are found in Arctic tundra permafrost and in deep-sea sediments along continental margins.
✅ Statement 3 – Correct: Methane in the atmosphere oxidizes to carbon dioxide through hydroxyl radical reactions after approximately 12 years, though CO₂ persists much longer in the atmosphere.

📝 Short Notes: Methane Hydrates

• Structure: Ice-like crystalline solids where methane molecules are trapped within water molecule cages, stable under high pressure and low temperature.
• Major Locations: Arctic permafrost regions and seafloor sediments on continental margins (300-500m depth), particularly offshore India (Krishna-Godavari basin).
• Climate Risk: Methane is 25-30 times more potent as a greenhouse gas than CO₂ over a 100-year period; release creates positive feedback loop.
• Oxidation Process: Atmospheric methane oxidizes via hydroxyl radicals (OH) to CO₂ with an average lifetime of ~12 years.
• Potential Resource: Estimated global reserves exceed conventional natural gas; India conducted successful extraction trial in 2019.
• Destabilization Triggers: Rising ocean temperatures, pressure changes, and permafrost thawing can release stored methane.