A significant fraction of the extra carbon in the atmosphere and ocean is attributed to “land use changes” which in fact basically means soil loss and forest loss due to agriculture.
Amid his misconceptions about climate science, Freeman Dyson’s most cogent point has always been that we can in principle sequester carbon using biological processes. The details are dubious, but the basic idea still holds some appeal.
Scientific American reports on a small project deployed to do a version of this which failed when cap-and-trade failed in the US and the Chicago Carbon Exchange failed along with it. But the idea of the soil as an essentially infinitely expandible carbon reservoir is something I’d like to see properly refuted, or else more seriously pursued.
I am finding it difficult to find quantitative information on this.
I expect that in the short run soil sequestration mediated by biological processes cannot keep up with fossil fuel burning in terms of rate.
But how long would it take to catch up? Can the process be accelerated? Given extra carbon can extra minerals and appropriate biota be combined with it to deepen the soil layer? How deep can the soil get? Is there a maximum?