Remember the USS LIBERTY, Biotches.
Spud Murphy
Or, we can just stop emitting the pollutant in the first place. Common sense really...
Spud, of course we should , and the article acknowledges this, but we also need to reduce what is already there. This is a great, practical idea using existing technology. There are obviously a number of challenges when you upscale to the extent needed but it is great to see the "out-of-the-box" thinking which is producing a practical solution that is not just "pie-in-the-sky". Pun intended.
Malcolm Jacks
Good stuff, keep it up.
To refine this idea, maybe the light but strong materials conceived for space elevators could tether a fleet of balloons and dry ice makers in-position above a deep ocean trench. After being brought down to the surface in carbon fiber pressure vessels, the vessels could then be transitioned through a platform on the ocean surface. The containers of dry ice could then be dropped down to the depths where the pods would release their dry ice under pressure. This would avoid the need for any intermediate re-compression before disposal. And the trench could also be deep enough to ensure the CO2 would remain sequestered. High winds might also help keep everything aloft. But, if too windy, perhaps the collecting flights could be timed to drop the containers directly into the deep trench (and later recovered). Everything benefits from the involvement of more industrial engineers?
If I was an alien race, travelling around the galaxy, looking for a planet to colonise, and came across the Earth, and decided that it was perfect, except for the animal life that called itself humans, that was busy destroying the planet so would need to be removed. All I would need to do, is reduce the atmospheric CO2 to 150 ppm, and all plant life would start to die, closely followed by animal life, the humans would probably be the first.
Then when they were gone, or reduced to manageable numbers, the CO2 could be increased and the planet returned to normal.

However, as the humans are doing it for me, all I have to do is sit back and wait!

CO2 is not a pollutant, its essential for all carbon based life on the planet!
Tie this idea in with tourism/recreational activities. Add a gondola so paying passengers can spend a day of splendid isolation at altitude, or in skydiving lessons, or even conducting scientific experiments. Add telecoms equipment in the way Project Loon envisioned and there's lots of opportunities for some extra side-money this company can make.
Why don^t utilize unmanned airships? They can be powered by PV film and be always available and with moving capabilities.
Trees, Trees, Trees
Worzel, CO2 doesn't directly pollute, but it causes solar heat to get trapped - for every degree rise we lose 25% of global cereal production. And it ups the acidity of the sea, which is 25% greater than in pre Industrial Times.