Do you have to decide at very start of project if you want 25 or 100 year permanence? Is there a period where you can upgrade or downgrade. I can't imagine why you would elect a 100 year permanace before your first carbon testing (after baselining). That would seem an extremely risky thing to do. But I can see it as plausible after some verification your practice change is working.
I don't really understand the baseline rationale particularly with biodiversity. We have baselines everywhere. They are over the fence in the neighbors. Surely a baseline that's combination of modelling and measuring can be produced wirh high accuracy. We do this for climate change itself. If we can model reasonably accurately into the future surely, with the benefit of actual historical data we can model and measure back to a past and then fwd to a likely present. I know exactly what my soil would be like if I'd stuck to status quo management. It would be very close to an average if my surrounding neighbors. We pick a start date say 2000, there's your baseline.
