Well, anyone can decide to run potential future capture plants, cleaning up after others (that includes the previous generations), while everyone would have to agree to reduce emissions.

What looks inefficient as far as pure physics goes, might be very efficient politically. Build some solar power plants in the Sahara, use the energy to sequester carbon, pay poor countries like Niger some money for that, reduce the current migration stream to Europe by creating local green jobs - that does not sound too bad.