About half the mass of a tree is carbon. Seeds cost a couple cents. Plant a big tree (oak, let’s say) in an area where it’s unlikely to burn down and it’s probably good for 1000kg of carbon storage.
This is addressed on the website. I think at scale afforestation becomes a very risky prospect financially and requires a much larger amount of land putting biodiversity at risk and infringing on agriculture as apposed to the proposed CO2 remove technology. The cited paper for this on their website is unfortunately paywalled but I would be really interested in finding out more about this.
Big brain time. Biodiversity isn’t at risk if you plant different kinds of trees in different places. You don’t need to build a massive forest in any given place. Simply rebuilding the forests we used to have would go a long way.
No one is advocating for stopping conservation efforts or reforestation. But we will need a combination of solutions in order to reverse existing damage and meet targets.