It is more likely than not that an Earth-based space elevator will be built sometime in the next hundred years.

At least one will be attempted. I think there's a good chance that there will be complications.

i acctualy attend a university lecture about that not long ago... crapp, but it might come sooner than 100 ys. like Rorek i also think it might not work out too well...

Some optimistic estimates think it might be feasible within thirteen years. But there are a lot of technical problems that haven't been solved yet (wireless power distribution, better radiation shielding, tracking and dodging orbital debris, manufacturing ridiculous quantities of near-perfect single-wall nanotubes), so predictions are just a matter of guessing how fast technology is going to change.

A hundred years is a long time, though. If we don't build one by then, it will probably be because either a) it's just not physically possible, or b) earth is too busy with other, more pressing problems (like wars, natural disasters, or a severe economic collapse).

I thought the radiation shielding largely wasn't an issue until you want to transport living beings, at which point, you just need to put them behind their food and water, and they'll be fine. I'm most concerned about orbital debris: Low earth orbit has an increasing amount of junk moving really fast that could seriously damage the tether. A significant question is whether the other technologies (climber power, nanotube tether) required for the space elevator happen before orbital junk is likely to break the tether while it's being thickened to the strength it would need to be to bring up large cargoes and withstand hits from small objects.

I imagine that once the space elevator is in use, it will be handy enough that it will create an incentive to clear up orbital debris, but that's a pretty tough task, really. Maybe you could hang a big net from other tethers to catch debris around the main elevator tether(s).

cf Arthur C clarke's Fountains of Paradise...

Developments in nanotubes etc might really make such a dream a reality.