There is already enough land available for enough new native trees to capture more CO2 than is emitted into the atmosphere each year. This is before considering recovery of additional brownfield sites, becoming more efficient with industrial and agricultural land usage, and setting more land aside for planting additional trees.

With the full potential unlocked, we'd be able to plant so many trees that they'd capture 2x or more of the total CO2 emissions (total emissions, not just the airborne excess) which means we'd start capturing the past excess emissions as well.