An Arizona company, GRT, is the subject of a Guardian piece about using a machine to extract CO2 from the air. According to GRT it can build scrubber units each able to collect a ton of CO2 per day.
The article -- using a cliche I particularly hate -- stresses the concept is "not a magic bullet," as it would take millions of the machines to handle all of our carbon emissions. But while it doesn't solve the problem by itself, "this can help" and "this will help," says Richard Lackner, a Columbia University physicist who leads the team building the scrubber.
In other words, CO2 scrubbers are neat ideas that might be technically possible, but are a long way from implementation. What they need to do is miniaturize them, and install them in CO2 producing machines and processes.
This reminds me of another technological fix-it I was recently alerted to, a marine "upwelling pump" by a start-up called Atmocean. The idea is to increase oceans' ability to sequester CO2, by pumping more cool water to the surface, stimulating algae growth. The algae would soak up CO2, et voila.
Atmocean says it would deploy their upwelling pumps at 2 km intervals across 80% of the oceans.
Do you know how much of the Earth's surface is ocean? Neither did I: 361,800,000 square kilometers; 80% of that is 289,440,000 square kilometers. I calculate 72,360,000 pumps would be needed.
I have no idea what one pump would cost. But if it were $10,000, the total cost would be 1/100th of the $70 trillion global pool of money (all the money in the world).
So -- technically possible, but highly unlikely.
And I'm not crazy about the idea of messing with the ecology of the oceans. Yes, what they're doing is exploiting a natural process. But there's nature, and then there's nature. Atmocean doesn't mention on their website that the oceans are already absorbing greater quantities of CO2, with the result that the oceans are acidifying.
Along with acidity comes lower presence of carbonate, which interferes with marine species that need calcium carbonate to make shells and skeletons.
Most of that acidic water used to be only at lower depths -- the water Atmocean proposes to bring to the surface.