Time to go on the record

[a geek named Bob]

47. The resources used to build these balloons, in my design,

would be the excess CO2 and Methane.

Also, the areas of the balloons not used to power the chillers could be used to provide power to the land anchor points. Or you could power nutrient enriching sea farms. Or you could run a hydrogen plant to power a community. Or you could power a whole lot of houses/communities. I'm figuring on combining the lot into a down-market arcology. (It's not in this set of numbers, but it wouldn't be too hard to start running the numbers.)

You wouldn't have to cover the whole of the arctic. Matter of fact, you'd need around 1/5 of a percent of the total Arctic area. As to the "unrelenting shade," why not keep these structures moving around? Use the winds, and some of the excess power, to just move the structures.

Why not use the balloons to float seawater carbon sponges? You could place these around in areas with currents, and "clean" the oceans (slowly) of the excess carbon.

We are tool-makers, we can solve our problems.