I subscribe to the excellent daily newsletter The Browser, which has recommendations of 5 interesting articles that I would otherwise miss. It recently linked to an article in Strelka Mag that makes it clear that pulling carbon out of the atmosphere to reduce global warming is a big undertaking:
Keynesian thought-experiment in climate change. If we rely on carbon sequestration to get atmospheric carbon concentrations down to a more livable 350ppm, we will recover enough carbon to fill 138,462 pyramids, each the size of the Great Pyramid at Giza; we could build 3.79 great carbon pyramids every day for 100 years. "Beyond providing employment and sequestering carbon, these pyramids would do nothing. In as much as we understand this scheme cannot be built, we suggest that it must be"