I don't have the science to analyse their arguments so I'm interested in your opinions.
I'm afraid to say that while I think methane is a potentially very serious threat I have trouble taking stuff from Malcolm Light seriously in relation to this.
I've seen too many bits of junk (as opposed to science) in his stuff before to want to do more than very superficially glance at text of that length (it seems to contain some weird idea of a new source of methane, which instinctively I'm lumping in with his "invisible methane veil" from an earlier article).
That said I personally favour the Shakhova/Wadhams side of this debate - that massive abrupt releases are possible. I also personally think they likely at some point but it seems impossible to predict when they would occur (the risk factors would seem to increase as the Arctic becomes seasonally ice free).
I think there is no need to add junk science to what we already know about the methane situation - it's quite serious enough - and it can only mislead and misinform people to put out information that isn't rationally sound.
For methane stuff I strongly recommend the robertscribbler blog (plenty of past articles about methane, and no doubt will be more in the future):
http://robertscribbler.wordpress.com/Not only does he seem to do better at referencing the actual science than the Malcolm Light stuff via Arctic News, but you can actually engage him in dialogue and challenge statements where appropriate. In the past when I have tried to query statements on Arctic News my comments haven't even been approved for anyone to see, much less responded to.