I've always considered myself a long-term thinker: the primary importance of the present is the impact it will have on the future. This point came up over dinner last year with Dr. Jill Tarter in relationship to both her specialty, interstellar communications, and to more worldly concerns like ecology and the likelihood of humanity's eventual extinction.
She pointed me to the Long Now Foundation as a seminal effort towards this kind of mindset; I find their focus on the coming ten millenia admirable, if still somewhat short-sighted from the perspective of ecology, evolution, and sustainability. Nevertheless, I hope they eventually build their clock.
Just as a bookmark, I ran across The 10,000 Year Blog, which concentrates on long-term thinking, with an eye toward data preservation.
On the sustainability front, I recently found an example of real-world arcology discussion. Normally this kind of thing restricts itself to science fiction. Not that I don't also think they're a little nuts, since they manifestly fail to even begin thinking about how one transitions from the current state of affairs to the "arcological" city.
To return to the point raised in the first paragraph, my take on the question was that humanity either will or will not become extinct at some time in the future. In the case that it does not survive, the Earth's biosphere will recover in interesting and unpredictable ways, just as it has after every previous mass extinction. Naturally, there's no guarantee that intelligent life will arise again; that seems to be pretty hit-and-miss, although the fact that it only took mammals 100 Myrs or so to get there is not altogether disheartening.
Should humanity survive in the far future, we may assume that it has come to co-exist stably with its environment, since it is unlikely that it could survive perpetual chaos (if things look chaotic as far as you can see, look farther), which can happen in one of three basic ways. First, we may reach a stable equilibrium with the Earth's ecology; second, we may eliminate the ecology and thus inhabit a totally artificial biosphere; third, we may abandon the planetary environment altogether, by moving into space.
This, I think, is pretty well-founded reasoning. If one were to ask for my own opinion, I would speculate that things don't look good for biological homo sapiens, on the simple basis that almost no complex life forms have persisted for more than a few hundred million years. And crocodiles, we ain't.
On the other hand, I would hold out a tentative hope that our intelligence, and perhaps even some scrap of our own civilization, will survive in our descendants, be they AI robots, bioengineered humans better suited to ecological equilibrium or space travel (or both), or what have you. As I write that, I can hear my DNA complaining that I'm supposed to want to perpetuate it, but perhaps we can all be grown-ups and decide that our mental genes will do, whatever those may be.
I have been encouraged by multiple people to start a blog to document my adventures in Israel, and other locations I may visit on my upcoming adventure. I think this is an excellent idea, which means it's time to become a blogger.
I should also invest in a digital camera. Nothing so expensive that I'd be heartbroken if it didn't come back with me. CF storage would be primo, since I can then offload them to the Gmini drive without an intervening computer.