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How is methane removed from the atmosphere and does a methane sink play a role in biology like CO2 does through photosynthesis?

arrosenberg 7y ago
It decomposes to CO2 and water vapor over about 10 years. The more methane we pump out, the longer decomp takes because there are fewer atmospheric hydroxyl radicals to drive the reaction. The methane cycle I'm familiar with is related to things dying and getting buried underground or in the ocean. I don't think there is any comparable process to how photosynthesis consumes CO2. There are methanogen bacteria who consume it, but that's probably not a globally scalable solution. I think it would be cheaper just to capture and store it.
- sword_smith 7y ago
  This is really fascinating, thanks for the clarification. I know that data for CO2 concentrations in the atmosphere go back at least 541m years, i.e. the whole Phanerozoic. Does a similar dataset exist for methane?
  - sword_smith 7y ago
    The biggest spike in the Phanerozoic was at the Permian extinction event 251m years ago and was caused by huge volcanic eruptions in Siberia that burned off coal deposits created in the Carboniferous era. See Figure 7 in this publication. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GB002985 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200...
- sitkack 7y ago
  Interesting, https://en.wikipedia.org/wiki/Hydroxyl_radical https://en.wikipedia.org/wiki/Hydroxyl_radical https://www.sciencedirect.com/science/article/pii/S092575351100186X https://www.sciencedirect.com/science/article/pii/S092575351... I wonder what the feasibility is in seeding the troposphere with hydroxyl radicals to accelerate the breakdown of methane?
  - marcosdumay 7y ago
    Water (the stable form of hydroxyl + hydrogen, we can't disperse radicals at the atmosphere) is a powerful greenhouse gas and will offset a lot of the cooling you may get by it.

arrosenberg 7y ago

It decomposes to CO2 and water vapor over about 10 years. The more methane we pump out, the longer decomp takes because there are fewer atmospheric hydroxyl radicals to drive the reaction. The methane cycle I'm familiar with is related to things dying and getting buried underground or in the ocean. I don't think there is any comparable process to how photosynthesis consumes CO2. There are methanogen bacteria who consume it, but that's probably not a globally scalable solution. I think it would be cheaper just to capture and store it.

sword_smith 7y ago
This is really fascinating, thanks for the clarification. I know that data for CO2 concentrations in the atmosphere go back at least 541m years, i.e. the whole Phanerozoic. Does a similar dataset exist for methane?
- sword_smith 7y ago
  The biggest spike in the Phanerozoic was at the Permian extinction event 251m years ago and was caused by huge volcanic eruptions in Siberia that burned off coal deposits created in the Carboniferous era. See Figure 7 in this publication. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GB002985 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200...
sitkack 7y ago
Interesting, https://en.wikipedia.org/wiki/Hydroxyl_radical https://en.wikipedia.org/wiki/Hydroxyl_radical https://www.sciencedirect.com/science/article/pii/S092575351100186X https://www.sciencedirect.com/science/article/pii/S092575351... I wonder what the feasibility is in seeding the troposphere with hydroxyl radicals to accelerate the breakdown of methane?
- marcosdumay 7y ago
  Water (the stable form of hydroxyl + hydrogen, we can't disperse radicals at the atmosphere) is a powerful greenhouse gas and will offset a lot of the cooling you may get by it.