The idea of a space elevator is very very cool (I've not read Clarke's book, but wasn't it "The Fountains of Paradise"?) but, in addition to the environmentalists complaining, think about what a remarkable target that would be for terrorists. Niven discusses that in "The Barsoom Project" Imagine a cable strong enough to work as a space elevator wrapping most of the way around the equator after a terrorist strike. (geosynch orbit is about 22,000 miles up... almost the circumference of the planet)