[_Nat_]

> From what I know, carbon capture over a field is not exactly a solved problem.

Doesn't appear to be capture-capture over a field. Instead:

> Navigator’s project would have laid pipelines across five US states—South Dakota, Nebraska, Minnesota, Iowa, and Illinois—to collect CO₂ from ethanol and fertilizer plants and pipe the gas to an underground storage site in Illinois.

Sounds like they were planning on point-source capture, which is generally a good bit more efficient than open-air capture.

If it were carbon-capture over a field, then it'd probably be under the category of "open-air capture" -- which is technically easy to do (as capture in general is; we've had CO2-capture technology since the 1930's), just more costly (since it's less thermodynamically efficient to capture from a low-concentration source like the atmosphere, relative to capture from a high-concentration source like the flue-gas from a plant).

Capturing CO2 from point-sources (like the flue-gas from plants) tends to be relatively efficient, which seems to work out better both economically and environmentally.