The largest climate opportunity from conventional agriculture is that we can enable the remaining land resources to revert to their natural vegetation or reforestation. The word opportunity is not random here: Reforestation is our greatest organic tool for carbon sequestration, point-blank.
However, there are opportunities for carbon sequestration in organic farming as well. Firstly, produce comes from plants (yes, for real!) which capture carbon (indeed!). More plants? More carbon sequestration! Moreover, soil in land used in conventional farming loses carbon. If the same piece of land is used for organic farming, the soil will be capturing carbon until it reaches an equilibrium [7].
Nevertheless, even in this scenario, the carbon sequestration opportunity is larger if we use the land for reforestation. What actually happens with land is only for time to tell.