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 the atmosphere oxidises to carbon dioxide after a decade or two.
Select the correct answer using the code given below:
- 1 and 2 only
- 2 and 3 only
- 1 and 3 only
- 1, 2 and 3
Explanation
Statement 1 is correct
- Methane hydrates (clathrates/gas hydrates/methane ice) are formed when hydrogen-bonded water and methane gas come into contact at high pressures (due to depth) and low temperatures in oceans. They are crystalline ice structures consisting of a methane molecule surrounded by a cage of interlocking water molecules. Methane hydrates are also trapped in permafrost (permanently frozen soil). It cannot be brought to the surface, as reduced pressure and increased temperature will cause the ice to melt and the methane to escape. Ocean acidification, climate change, or other anthropogenic disturbances, such as deep-sea mining, can destabilise clathrates (which are abundant in the ocean) and release vast amounts of methane, which can lead to mass extinction.
Statement 2 is correct
- Significant methane hydrate reserves are found in permafrost regions like the Arctic Tundra and beneath the ocean floor.
Statement 3 is correct
- Methane is oxidised in the atmosphere after a decade or two. Once oxidised, the carbon in each methane molecule is transformed into CO2, which remains in the atmosphere for another century or more.
- This creates a two-fold impact: first from the methane’s immediate warming effect, followed by the longer-lasting influence of CO2 produced through atmospheric oxidation.
