Quantification of peatland-mediated feedbacks to the climate system

Peatlands are important carbon reserves in the terrestrial ecosystem and cover 3% of the terrestrial land surface. Peatlands have stored around 350-500 Petagrams [10¹⁵] of carbon over the last thousands of years, comprising around 30% of the present-day soil organic carbon pool. Peatlands share many characteristics with upland mineral soils and non-peat wetland ecosystems. However, they constitute a unique ecosystem type with many special characteristics, such as a shallow water table depth, carbon-rich soils, a unique vegetation cover, spatial heterogeneity, anaerobic biogeochemistry and permafrost in the high latitude regions (>45°N). The recent changes in climate and land-use patterns have disturbed the Earth’s climate-carbon cycle equilibrium. These changes trigger some potentially important land-surface feedbacks, which will further modify the Earth’s climate. The ongoing changes in peatland carbon balance as a result of climate warming have the potential for strong positive and negative feedbacks to climate, but these impacts are poorly constrained. To assess the importance of these feedbacks, the interactions between the peatland carbon cycle and climate should be taken into account. However, the absence of peatlands in current Earth system models limits our understanding of the peatland-mediated feedbacks at different scales. LPJ-GUESS peatland-vegetation model showed a reasonable demonstration of capturing the right carbon accumulation rates and permafrost dynamics at different spatial and temporal scales and will be further improved and employed to quantify the hypothesized peatland-mediated feedbacks when coupled with regional/global climate models.