just recalling what a professor said on the subject - in the short term, those areas that gain a suitable climate for agriculture will take decades to build soi

just recalling what a professor said on the subject - in the short term, those areas that gain a suitable climate for agriculture will take decades to build soil up to what agriculture requires. Places where it was too cold to grow crops won't have had enough wild biomass to build a strong soil base, so there will be a 'gap' where many places that had a climate suitable to producing a lot of biomass no longer do but places that gained a climate suitable for producing a lot of biomass don't yet have the right soil ecology. Of course, human activity could speed up the transition for these areas, but soil building is a quirky technology that's hard to scale up.