There are environmental changes to Earth but there is also war and we discover over the course of this series, and hopefully future series, what has really happened to Earth. We leave the question hanging as to whether Earth is still habitable by human beings. You're not going to find that out just yet.
Interesting. I can't think of another film/show with quite that approach; usually either Earth is still around but basically a craphole (see: the Alien series), or it's kaput (see: Firefly and Serenity). Either way, it's pretty well defined. (I wouldn't count BSG because that's a step further still, in that for most of the series whether or not Earth exists is up for debate.)
I know UK series can run as little as six episodes or as many as thirteen, though Doctor Who, Torchwood and Law & Order: UK likely film more episodes with the international market in mind. The original reports on Outcasts referred to it as a mini series rather than a series and it sounds as if there are no plans, at this point, to film more than eight episodes. I'm just sticking with the initial classification until there is more information from the BBC. Plus, I'm not sure how it's handled in the UK, but there are legal issues to be resolved if an actor is signed to two series airing on two different networks in the US. Maybe Jamie was able to appear in Outcasts because, right now, it's a limited run?
It's a large cast too. It's possible he may only film for a few days and then have a stretch of time off to go back home. And, with the summer coming up, they could spend time with him in South Africa. It's probably not much worse than when he was filming BSG.
it's good that we know a bit more about the serie and what we can expect to see....hope we get a trailer teaser soon *keep my fingers crosses* As for jamie and his family, yes, maybe Kerry and the girls will join him this summer *winks*