A map of NEAs, many of which are PHAs: http://rt.com/news/nasa-hazardous-asteroid-map-575/ DA14 was just a warning. We better hedge by colonizing the moon ad mars.
I think that you should worry a lot more about terrorists crossing our borders and bringing in some 150 pound tactical nuclear weapons into the country and demolishing city after city with them.
I would worry about AI gaining consciousness (within a hundred years) before being concerned about the next ice age (in a thousand years?) even before potentially hazardous asteroids (tens of thousands of years?). http://www.youtube.com/watch?v=pUe9P24ZCmo
I watched this on youtube a couple of weeks ago: https://www.youtube.com/watch?v=TOBgPZFFlFY about evacuating the earth. It's always about spaceships leaving Earth, but are there any considerations of living deep in the ocean near hydrothermal vents, or deep underground? In the last ELE, they say it was mammals that lived underground that survived the extinction, it might be a more viable approach.
We have known about his for years. People are over terrorism so now the next scam is an asteroid strike. Watch over next few years how we start to blow money on it. Nothing our government says can be taken at face value. Always some Kleptocratic move behind it.