[KenWittlief]

I think the most important challenges we will face will deal with survival - as a culture, nation, species, or even life on all of earth itself.

On any day we could detect a comet or asteroid heading our way, too big to stop or alter. The challenge then will be how do we survive the impact, or how do we relocate life to another planet - either Mars or in another solar system?

Or do we build a colony in space and wait till the earth can be inhabited again?

Things like oil and transportation will come and go - and the transisions will be gradual. We are not going to run out of oil overnight. It will slowly become more and more expensive, and humanity will adapt and improvise, like we always have.

But in the bigger sense, I dont think our most important challenges are engineering problems, they are social problems. Technology enables us to do what we want more efficently.

The real problem is what some people want. Death and destruction.

Somehow humanity needs to grow and mature past that.