(There's your "replacement cost once global warming ruins the current Earth" pegminer. Expensive, but we could do it if we want to. Prevention is usually less expensive - BUT NOT ALWAYS.)
Besides, one could work out every detail of Iron fertilization and sequester whatever amount of fossil fuel origin carbon for less than the "loose change" of either prevention or drastic space mirror correction.
Iron fertilization…
http://en.wikipedia.org/wiki/Iron_fertil...
emulates the natural fertilization of the iron deficient ocean ocean waters in causing blooms of diatoms,
http://en.wikipedia.org/wiki/Diatom
which naturally form siliceous shells that resist their being eaten or decaying and so releasing their carbon chemistry interiors into the environment on their death, but rather weigh them down and cause them to sink to the sea bed,
http://en.wikipedia.org/wiki/Pelagic_sed...
forming a natural disposal of the carbon
http://en.wikipedia.org/wiki/Biological_...
http://en.wikipedia.org/wiki/Carbon_sequ...
for man to copy.
If scientists were actually asking for that, it would probably cost... more money than that. And what would we build it out of?
So is that your estimate of the replacement cost once global warming ruins the current Earth?
And people think that action on global warming is costly--clearly inaction has a higher cost.
They cant build one in a computer . They will have to measure all the buildings , streets, sidewalks , all the signs every square inch and count insects and all the plants
