The pros and cons of Space Elevators were thoroughly discussed in correspondence related to a New Scientist article on the subject in November 2008. Below are my responses to one of the postings.

Unfortunately, you'll have to seach the NS archive to find the questions to which the various enumerated points are my responses! However, the gist of it is that, in my opinion, the idea - although theoretically good - is impossible to implement, due to a considerable number of insuperable practical difficulties - including that mentioned in the last entry.

1. Coriolis forces are not illusory - they caused the Torrey Canyon oil tanker disaster.2. Nobody has said much about car propulsion, so here are a few thoughts. 2.1 If you use a laser beam to power the car, how are you going to stop the beam burning through the cable when it's blown by the wind or wobbles due to physical effects? 2.2 Apart from that, how will the power be used? If for an electric motor driving the car against the cable, the cable will be pulled down as much as the car goes up (thanks, Mr. Newton). 2.3 Granted, you could overcome this effect by thrusters on the topside station, but even with efficient ion drives, the thrusters still need "fuel" - mass for ejection - which would have to be obtained from somewhere. If it had to be brought up from Earth, this would severely reduce the efficiency of the system.2.4 The ion drives would have to be directed away from the cable (symmetrically opposed) to avoid damaging it, so that would also reduce the efficiency of the system.2.5 If you used ion thrusters on the car for lift to avoid cable vertical reaction effects, 2.4 would apply here too - and again, as in existing rockets, you would be lifting the "fuel".3. Yes, there is power to be had in both the upper atmosphere and Van Allen belts - but exactly how will you harvest it? By beefing up your conducting nanotube elevator cable? How much PD would you get across the height of an elevator car - enough to power it?4. My thanks to Sandy Henderson for setting out clearly how what I consider to be one of the more practical ways of getting material into space - an evacuated "Destination Moon" maglev rail gun - would be implemented. And, by the way, if you only used it for materiel, not people (leave them to rockets), you wouldn't be limited to 6G. Standard MIL Specs call for 50G, and if you stepped that up to 100G, you would probably only need a 50 mile track - quite practical. As far as I can see, the only problem would be the impact load of the hypersonic shockwave as the projectile leaving the vacuum tube hit the (even thin) atmosphere.5. The balloon idea looks interesting, but has a very limited load capability. On the other hand, I think a "grown-up" White Knight with an added SCRAMjets and Spaceship One-style pods could carry significant loads of both materiel and people into orbit much more economically than the present VTO rockets.6. Would anyone like to calculate the increase in global warming due to all the power burned in PCs, NASA's supercomputers and worldwide Internet servers from the theoretical work, discussion and other correspondence on this to my mind dead-end subject?