WEBF,
I think you'll find the gist of that New Statesman issue (and the NS in general) is that we are far better of preventing global warming by investing in alternative energy and emission reduction.
Dreaming up threats resulting from climate change, beefing up the defence forces to protect against them, is not only closing the gate after the horse has bolted but missing the point of defence in that case.
As for the public/media being more amenable to increased defence spending;our illustrious leaders responsible for the commitment of such forces need to prove they can play with their toys sensibly before the public buys more in future. Post 2003 that ability hasn't been displayed particularly effectively.