I wonder what a series of huge (serious of hugh) methane ice burps would do? Large changes in weather, release of organics, etc.
Natural gas,
Troll A [Credit: Swinsto101]
colourless, highly flammable gaseous hydrocarbon consisting primarily of methane and ethane. It is a type of petroleum that commonly occurs in association with crude oil...
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The first discoveries of natural gas seeps were made in Iran between 6000 and 2000 bce. Many early writers described the natural petroleum seeps in the Middle East, especially in the Baku region of what is now Azerbaijan. The gas seeps, probably first ignited by lightning, provided the fuel for the “eternal fires†of the fire-worshipping religion of the ancient Persians...
http://www.britannica.com/science/natural-gas
I would think it would have to be VERY big for the Earth to notice.
This is what happened with a LARGE Carbon Dioxide release:
https://en.wikipedia.org/wiki/Lake_Nyos.
It COULD be Sirius!