What could occure in 2012, and if something does occur what are we capable of doing in order to preserve life?

To make myself a bit more clear I'll give an example. One thing that might occur is a astroid impacting the earth... (a few other things that I've hurd that is possible is a globle polarity shift, mive solar storms and numerous other possibles) uming this happens what can we do to preserve as much life as possible? The scale of the impact will ofcourse play a major role in what exactly we can do, however uming that is a global killer (something on a very large scale), do we have the technology to survive? Are we capable of evacuating people into space and sustaining life there untill they can return to earth, or are we capable of perhaps finding a way to survive on earth during such a catastrophe. I'd like to hear people's views on what could happen and if it does occur what we might be able to do to survive it.