Which of the following statements are correct about the deposits of ‘methane hydrate’?

1. Global warming might trigger the release of methane gas from these deposits.

2. Large deposits of ‘methane hydrate’ are found in Arctic Tundra and under the seafloor.

3. Methane in atmosphere oxidizes to carbon dioxide after a decade or two.

Select the correct answer using the code given below.

Correct Answer: 1, 2 and 3

Let us analyze each statement step-by-step to understand why all three statements are correct:

1. Global warming might trigger the release of methane gas from these deposits:
Methane hydrate (also known as methane ice or fire ice) consists of methane molecules trapped inside a cage-like structure of water ice. These hydrates remain stable under conditions of high pressure and low temperatures. As global temperatures rise due to global warming, ocean temperatures and continental temperatures increase. This destabilizes the frozen hydrate structures, releasing the trapped methane gas into the water and ocean atmosphere, which can further accelerate climate warming.

2. Large deposits of ‘methane hydrate’ are found in Arctic Tundra and under the seafloor:
Methane hydrates require specific temperature and pressure conditions to form and persist. These conditions are abundant in the high-pressure, low-temperature marine sediment environments beneath the deep ocean seafloor as well as under the permafrost layers of the Arctic Tundra.

3. Methane in atmosphere oxidizes to carbon dioxide after a decade or two:
Methane (CH₄) is a potent greenhouse gas, but it has a relatively short atmospheric residence time compared to carbon dioxide. In the atmosphere, methane reacts predominantly with hydroxyl radicals (OH) through chemical oxidation. Over an average atmospheric lifetime of about 10 to 12 years (a decade or two), methane oxidizes into carbon dioxide (CO₂) and water vapor (H₂O).

Thus, statements 1, 2, and 3 are all correct.