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The Story of the Second Greenhouse Gas – CH4
- The Permian Extinction – Methane hydrates:
- The carbon isotopes suggest what might have caused the temperature increase.
- Carbon 12 and Carbon 13 exist in different ratios in different places. Photosynthesis captures Carbon 13 preferentially, so organic CO2 tends to be high in it.
- The ice cores show a massive shift towards the light isotope, carbon-12, exactly at the time of the big extinction. ...
- The extra carbon-12 was probably frozen deep under the oceans in the form of methane hydrates.
- These are extraordinary accumulations of carbon-12-rich methane locked up in cages of ice at very high pressure. If the atmosphere and oceans warm up sufficiently, these gas reserves can suddenly melt and release their contents in a catastrophic way.
- Some methane hydrates are stored in permafrost as well.
- Source Wikipedia article “The Permian Extinction”