Previously, previously, previously, previously, previously, previously.
In the same neck of the woods the methane assists in prying open another door to the underworld: From a small artificial clearing in the 1960's the Batagaika slump erodes steadily outward, releasing who knows what from 200,000 years of slumber in permafrost turned runoff.
Ever wonder whether Russia’s blasé stance on the environment combined with enthusiastic hydrocarbon extraction might be an intentional strategy to accelerate global warming? Huge swaths of previously unproductive Siberian coldlands could become arable, productive agricultural assets. While at the same time the agricultural heartlands of Russia’s global rivals could become useless dry desert. That could flip the global power structures just with who dominates the wheat market.
You are assuming those Siberian coldlands have arable soil. There's more to agriculture than just temperature.
There are challenges for sure. Soil can be improved incrementally with amendments and wise crop rotation. There’s millions of acres of previously sterile gravelly desert now bearing cash crops from North Africa through Central Asia. Fixing the soil is hard, but not as hard as fixing the ambient temperature.
What used to live at the bottom? And will it be back to feed its brood, or are they now capable of surviving on their own?