But to burn it you'd have to collect the methane and concentrate it first, otherwise at low concentrations it is unlikely to ignite. Given that the Siberian arctic is vast and remote, I don't think this is a practical proposition.
You're probably right though, it's probably not too diffuse and generally impractical.
True, although it decays to CO2 and water after about twelve years [1].
[1] https://en.wikipedia.org/wiki/Global_warming_potential#Value...
Where does this number come from? Heat capacity is almost the same for CH4 and CO2 (and half of that of H2O).
Not to mention that the formulas are incomplete.
This is the part I'm not so sure about. Physicists tend to not bother with climatology.
Edit: for example, Radiative Forcing in the AR5 http://climate.envsci.rutgers.edu/climdyn2013/IPCC/IPCC_WGI1...
The main author is Drew Shindell, Professor of Climate Studies, PhD in Physics.