Ecosystems with high soil carbon densities include the peat bogs in Ireland with up to 3000 tonnes ha-1 , the Cuvette Centrale swamp forest peatlands in Congo with an average of ~2200 tonnes ha-1 , the Arctic tundra with an average of ~900 tonnes ha-1  and the mangrove peatlands in Kalimantan, Indonesia, with an average of 850 + 320 tonnes ha-1 . Arctic permafrost contains 1400 + 200 GtC to a depth of 3 m, the largest soil carbon stock in the world . Globally, peatlands contain 470-620 GtC , of which boreal and temperate peatlands contain 415 + 150 GtC  and tropical peatlands contain 80-350 GtC . Other analyses increase the upper estimates for boreal and temperate peatlands to 800-1200 GtC .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report