The hysteria just doesn't stop. Time passes and things move on as if they never happened. The news is entertainment, without it being dramatic, it doesn't sell. When have these major scares ever been right?
I bet you could do pretty well right now selling fallout shelter kits and nuclear emergency preparedness kits.
The conversion on those ads should be just about insane right now.
It doesn't really matter though on a personal level all you need to do is turn off the news. 99% of it has absolutely no effect on you.
Global Financial Meltdown? Number of things I can do to mitigate it? None. Nuclear Meltdown in Japan? Number of things I can do about it? None. (Ok, I chipped for the redcross, but I'm not moving to Japan to help out, so it's effectively none) Stop worrying, and start living life. Go out and have beers with a friend. Talk to people and build a meaningful friendship. It will all have a much greater impact on your life than whatever is on the news.