Jay Manifold says we're still being too complacent. This is one of the stronger arguments for becoming a true space-faring civilization as soon as possible, to my mind.

He also links to this collection of textbook disclaimers, which seems to be pretty popular on blogdex right now:

This textbook suggests that the earth is spherical. The shape of the earth is a controversial topic, and not all people accept the theory. This material should be approached with an open mind, studied carefully, and critically considered.

I have to disagree with you here. We may be too complacent about the likelihood of nuclear war, some manmade plague, or a generic civilization ending event. However, I don't see our response to the threat of an asteroid impact as complacent. After all, we do have a preliminary detection system in place, and we are developing the technology that would go into future, far better detection systems. Further, we're developing technology that would be useful in deflection asteroids or in the worst case, building refuges (on Earth and in space) in case of asteroid impact.

After all, we do have a preliminary detection system in place, and we are developing the technology that would go into future, far better detection systems. Further, we're developing technology that would be useful in deflection asteroids or in the worst case, building refuges (on Earth and in space) in case of asteroid impact.

I didn't say we're doing nothing, but we could (and would) certainly be doing all those things with much more alacrity if we took the threat seriously.

Also nuclear wars and manmade plagues are much tougher problems to deal with than asteroid/comet protection, because they're caused by humans.

Hmmm...and interesting seed for a column there. "If we can put a man on the moon, why can't we..."

Thanks for the link. The question of just how highly this risk ought to be ranked is interesting, to say the least. My own sense is that amateur astronomers may play a significant role in mitigating it over the next decade, but a network of smaller (~1-meter) telescopes in space would be a great help.

A large impact is extremely unlikely, we would have to be terribly unlucky to have one strike in the next few decades. But - it makes it clear that we absolutely need to move into space. We can't just assume we will get there eventually. It is something that must happen.

And we COULD be unlucky.