On: How can we stop the CO2 that plants store from leaking back into the air?

[silverthorn]

> I think there's a nascent industry in converting biomass into biochar and sequestering it

To expand on that, biochar seems to be the majority of carbon removal delivered commercially to date:

https://www.cdr.fyi/

Of course the entire CDR industry is nascent.

Bio-oil via pyrolysis is another option. Charm Industrial is trying to scale that up.