Hm. https://www.nature.com/articles/s41467-021-23010-5
"Timescales of the permafrost carbon cycle and legacy effects of temperature overshoot scenarios" by deVrese and Brovkin 2021
They took one of the plant-soil models and looked in an overshoot scenario what the temperature rise and artificial sudden removal of atmospheric CO2 does to the soil and carbon store in the #Arctic.
The end result after adaption to new stabilisation level is: carbon store is only 40GtC lower than before the overshoot, ie a mere 4 years worth of current global fossil CO2 emissions.
This surprisingly (to me) low end result of -40GtC is due to increased plant growth from the temperature increase over pre-industrial, from the prolonged growth seasons, and a special Arctic circumstance of high Nitrogen availability that ensures nutrients for excessive plant growth.
But the "end result" comprises the whole adjustment period to a stabilised °C after the overshoot. Adjustment takes 1000 yrs in the model.
And in the interim periods, emissions from thawing permafrost do reach 1 to 1.5GtC each year, and for decades! The duration for this soil-atmosphere carbon flux depends on the level and duration of the temperature overshoot.
Of course, it also increases the #CO2 amount to be artificially removed to undo an #overshoot.
In the context of #RCPcollapse :
the toot above showed how natural CO2 removal after civilisation collapse leads to temperature reduction of more than 0.5°C within 30 years .
Now, while permafrost thaw is irreversible on human time scales, it won't continue in RCPcollapse. (Because Arctic permafrost has no general technical tipping point after which self-perpetuating or self-reinforcing processes would kick in. Such processes only exist in small areas, locally, with local-only tipping behaviour. See "Global Tipping Points Report" 2023, chapter on #cryosphere https://nora.nerc.ac.uk/id/eprint/536521/)
In RCPcollapse, the adjustment to the new equilibrium will take 1000 years – but there won't be a palpable increase in °C from the thaw.
Greg Cocks 
1 new picture from Copernicus 
