Also, you are evidently not an economist if you think the net output of CO2 from wood is zero. You'd make a good accountant though... maybe... nah, I doubt it. It's not an insult. Accountants and economists have very different ways at looking at costs. An accountant would see "tree absorbs CO2, CO2 is emitted, therefore zero". An economist would see "transportation, production, usage, refinement, all create CO2 as well, making the end result have higher CO2 than is efficient.".
Oh, man, you make a brain-fart like with the uranium and then you call me a poor material for an accountant. Have some modesty yourself.
Not to mention that anybody who proposes solar-collector satelites as a clean energy source forgets about, ehem, "transportation, production, maintenance". Mind you, that unless we get to build a space elevator(or better, space fountain), sending stuff into space is going to take whole lot more of energy than it produces.
In principle, though, it's a nice idea.
7m rise
This is the most often quoted estimate. However it's the runaway warming that presents the real danger.
edit:After checking the appropriate data, let me correct you on the uranium again:
uranium density=19,1g/cm
31 cubic meter of uranium = 19100kg
assuming it is commercial grade uranium, enriched so that it's U-235 component is around 3%, which gives 573kg of fissionable material. 1kg of U-235 after complete fusion can theoreticaly yield 2x10
13Joules of energy(after wikipedia), 1 cubic meter of uranium would yield 1146TeraJoules(10
12J) of energy.
The above is an ideal situation, as in reality only about 3% of U-235 undergoes fission before rising concentration of nuclear poisons prevents further reaction(and requires reprocessing, if economically feasible). So, in the (other-extreme) event of -not- reprocessing spent fuel after one cycle, 1m
3 would yield ~34,4TJ.
So the correct estimate would be between 1146TJ and 34,4TJ.
If it's not refined uranium that you've had in mind, then the above figure is lower by the factor of four.
Also, Watts are used to describe energy change over time(power). When used to describe a powerplant, it tells you how fast it is able to produce energy - a characteristic of it's design.
Should you assume, for the sake of argument, that all this uranium can be fissioned in one second, you'd get 1146TWatts-34,4TWatts. About million times more than you've assumed.
Only 3% of this becomes nuclear waste.
...while the remaining 97% is a dead mass, not yielding any energy... unless converted to U-239 or used in special-design reactors(fast reactor)... and then it does turn into radioactive waste.