Mark has again said something that I strongly agree with:

>I am firmly of the belief that the Earth is a preciously rare
>planet that deserves protection even if humanity grows beyond it.

I would categorize myself as a radical conservationist. I think the Earth is so precious that we should get most of the human race off of it and return the planet to wilderness. I'd like to see the Earth's resident population reduced by birth control to less than 1/2 a billion with the planet transformed into a giant nature park / museum. The only people permanently living on the Earth should be forest rangers, museum and tourist support staff. The greatest risk to the Earth is not comets and asteroids but having too many damned people living on it. I'd like the majority of humanity (multiple billions) living in sustainable habitats scattered across the Solar System. IMHO our single planet economy is exceeding the Earth's carrying capacity. I'd like to see a Solar System based economy that was a hundred to a thousand times larger than our current single planet version. With this much larger economy, I can imagine a huge anti-comet, anti-asteroid defensive system that could protect not only the prestine Earth but also the other human settlements of the Solar System. I might also add that this larger economy could also have the capability to build starships and explore beyond the Solar System.

In case your wondering, the best way to acheive this vision is to colonize Mars. Mars is the first step towards Solar System wide human settlement.

Gary