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The Story of the Second Greenhouse Gas – CH4
- The Permian Extinction – two burps
- The cause of the 2nd burp was probably global warming triggered by a first burp: huge releases of CO2 and CH4 from the Siberian Traps (in permafrost), which is heavier in C13 than the ocean hydrates. Methane is a greenhouse gas too, so a big burp raises global temperatures even..
- Normally, long-term global processes act to bring greenhouse gas levels down. This kind of negative feedback keeps the Earth in equilibrium.
- But what happens if the release of methane is so huge and fast that normal feedback processes are overwhelmed? Then you have a "runaway greenhouse". This is a positive feedback system: excess carbon in the atmosphere causes warming, the warming triggers the release of more methane from gas hydrates, this in turn causes yet more warming, which leads to the release of more methane and so on.