You can get a certain amount out of growing additional live biomass where there isn't any now. There was a supposition that one of the causes of the Little Ice

You can get a certain amount out of growing additional live biomass where there isn't any now. There was a supposition that one of the causes of the Little Ice Age was reforestation of the Americas after plagues wiped out 90% of the inhabitants. I don't know what the current state of that conjecture is, but I recall the amount of carbon taken up in the process was significant. If you found a way to eg forest the Sahara, it would be significant on a global scale. Not a one-and-done fix, but significant. Then you would either have to find new land to plant or cut down the trees and not burn them/mulch them to sequester more carbon, but a living forest holds a good bit on its own.