The scope and distribution of C-wetland

Wetlands have the highest ecosystem service value among all terrestrial ecosystems. Among their ecosystem services, carbon sequestration and its potential ability to mitigate climate change have been extensively discussed recently, not only in the academic community but in media during COP27 of UNFCCC and COP14 of Ramsar. In particular, peatlands—peat-accumulating wetlands—accumulate 600 Gt C globally. However, peatlands were historically exploited for their peat and reclaimed to other land-use types. In fact, the definition of peatlands is based on their resource value lying in the organic matter content in peat. Therefore, under goals of conservation and carbon neutrality, “peatlands” may not be a precise concept for estimating and conserving the substantial carbon stock of this type of wetland.

For highlighting the carbon stock of wetlands rather than considering their resource characteristics, a new systematic description of carbon-rich wetlands is needed for accurately understanding the distribution of the wetlands and for better conserving their carbon stock. Therefore, we propose a new term, “C-wetland,” for carbon-rich wetlands and map the global C-wetland distribution.