Northern peatlands are a large C stock and often act as a C sink, but are susceptible to climate warming. To understand the role of peatlands in the global carbon‐climate feedback, it is necessary to accurately quantify their C stock changes and decomposition. In this study, a process‐based model, the Peatland Terrestrial Ecosystem Model, is used to simulate pan‐Arctic peatland C dynamics from 15 ka BP to 1990. To improve the accuracy of the simulation, spatially explicit water run‐on and run‐off processes were considered, four different pan‐Arctic peatland extent data sets were used, and a spatially explicit peat basal date data set was developed using a neural network approach. The model was calibrated against 2055 peat thickness observations and the parameters were interpolated to the pan‐Arctic region. Using the model, we estimate that, in 1990, the pan‐Arctic peatlands soil C stock was 396–421 Pg C, and the Holocene average C accumulation rate was 22.9 g C·m−2 yr−1. Our estimated peat permafrost development history generally agrees with multi‐proxy‐based paleo‐climate data sets and core‐derived permafrost areal dynamics. Under Anthropocene warming, in the freeze‐thaw and permafrost‐free regions, the peat C accumulation rate decreased, but it increased in permafrost regions. Our study suggests that if current permafrost regions switch to permafrost‐free conditions in a warming future, the peat C accumulation rate of the entire pan‐Arctic region will decrease, but the sink and source activities of these peatlands are still uncertain.
High‐latitude permafrost regions store large stocks of soil organic carbon (OC), which are vulnerable to climate warming. Estimates of subsurface carbon stocks do not take into account floodplains as unique landscape units that mediate and influence the delivery of materials into river networks. We estimate floodplain soil OC stocks within the active layer (seasonally thawed layer) and to a maximum depth of 1 m from a large field data set in the Yukon Flats region of interior Alaska. We compare our estimated stocks to a previously published data set and find that the OC stock estimate using our field data could be as much as 68% higher than the published data set. Radiocarbon measurements indicate that sediment and associated OC can be stored for thousands of years before erosion and transport. Our results indicate the importance of floodplains as areas of underestimated carbon storage, particularly because climate change may modify geomorphic processes in permafrost regions.
more » « less- NSF-PAR ID:
- 10461403
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 46
- Issue:
- 4
- ISSN:
- 0094-8276
- Page Range / eLocation ID:
- p. 2121-2129
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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