Global peatland initiation driven by regionally asynchronous warming

Morris, Paul J.; Swindles, Graeme T.; Valdes, Paul J.; Ivanovic, Ruza; Gregoire, Lauren; Smith, Mark W.; Tarasov, Lev; Haywood, Alan M.; Bacon, Karen L.

doi:10.1073/pnas.1717838115

Cited by 104 publications

(107 citation statements)

References 38 publications

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“…The effect of climate change on peatland initiation and expansion is not well understood and currently a topic of active research (Morris et al, 2018). We found that peatland expansion is almost linear since the beginning of the Holocene (Figure 7a), leading to a total area of 3.1 million km 2 occupied by peatlands across the pan‐Arctic in by the year 2000 (Xu et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Modelling past and future peatland carbon dynamics across the pan‐Arctic

Chaudhary

Westermann

Lamba

et al. 2020

Global Change Biology

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The majority of northern peatlands were initiated during the Holocene. Owing to their mass imbalance, they have sequestered huge amounts of carbon in terrestrial ecosystems. Although recent syntheses have filled some knowledge gaps, the extent and remoteness of many peatlands pose challenges to developing reliable regional carbon accumulation estimates from observations. In this work, we employed an individual‐ and patch‐based dynamic global vegetation model (LPJ‐GUESS) with peatland and permafrost functionality to quantify long‐term carbon accumulation rates in northern peatlands and to assess the effects of historical and projected future climate change on peatland carbon balance. We combined published datasets of peat basal age to form an up‐to‐date peat inception surface for the pan‐Arctic region which we then used to constrain the model. We divided our analysis into two parts, with a focus both on the carbon accumulation changes detected within the observed peatland boundary and at pan‐Arctic scale under two contrasting warming scenarios (representative concentration pathway—RCP8.5 and RCP2.6). We found that peatlands continue to act as carbon sinks under both warming scenarios, but their sink capacity will be substantially reduced under the high‐warming (RCP8.5) scenario after 2050. Areas where peat production was initially hampered by permafrost and low productivity were found to accumulate more carbon because of the initial warming and moisture‐rich environment due to permafrost thaw, higher precipitation and elevated CO2 levels. On the other hand, we project that areas which will experience reduced precipitation rates and those without permafrost will lose more carbon in the near future, particularly peatlands located in the European region and between 45 and 55°N latitude. Overall, we found that rapid global warming could reduce the carbon sink capacity of the northern peatlands in the coming decades.

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Section: Discussionmentioning

confidence: 99%

Modelling past and future peatland carbon dynamics across the pan‐Arctic

Chaudhary

Westermann

Lamba

et al. 2020

Global Change Biology

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“…Although taken individually their size is negligible compared to vast high latitude or tropical peatlands, they store between ~1,200 (Cooper et al, ) and ~1,500 Mg C ha −1 (Hribljan et al, ), which concurs with the average storage of 1,330 Mg C ha −1 defined for boreal peatlands (Gorham, ). Summed together mountainous peatlands may represent a valuable carbon stock that needs to be defined globally, understood (Morris et al, ) and preserved through current global changes. Because of their remote location, peatlands in mountains are much less studied than their lowland counterparts and only a few studies have investigated their carbon dynamics.…”

Section: Introductionmentioning

confidence: 99%

Peatland Contribution to Stream Organic Carbon Exports From a Montane Watershed

et al. 2019

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Mountains contain many small and fragmented peatlands within watersheds. As they are difficult to monitor, their role in the water and carbon cycle is often disregarded. This study aims to assess the stream organic carbon exports from a montane peatland and characterizes its contribution to the water chemistry in a headstream watershed. High frequency in situ monitoring of turbidity and fDOM were used to quantify respectively particulate organic carbon (POC) and dissolved organic carbon (DOC) exports at the inlet and outlet of a peatland over three years in a French Pyrenean watershed (1,343 m.a.s.l.). The DOC and POC signals are both highly dynamic, characterized by numerous short peaks lasting from a few hours to a few days. Forty-six percent of the exports occurred during 9% of the time corresponding to the highest flows monitored at the outlet. Despite its small area (3%) within the watershed, the peatland contributes at least 63% of the DOC export at the outlet. The specific DOC flux ranges from 16.1 ± 0.4 to 34.6 ± 1.5 g m 2 year −1 . POC contributes 17% of the total stream organic carbon exports from the watershed. As the frequency of extreme climatic events is expected to increase in the context of climate change, further studies should be conducted to understand the evolution of underestimated mountainous peatland carbon fluxes and their implication in the carbon cycle of headwaters. Plain Language SummarySince the last glacial period, peatlands have accumulated large stocks of organic carbon. Despite representing only 3% of global continental surfaces, they store about 22% of the continental soil carbon stock. In the context of global change, peatland carbon sequestration capacity needs to be carefully monitored. In addition to greenhouse gas exchanges with the atmosphere, determining this capacity requires the quantification of aquatic organic carbon exports. Aquatic organic carbon exports have rarely been investigated at mountainous peatlands. Moreover, global change is expected to drastically modify mountain hydrology, influencing aquatic carbon exports and carbon balance of mountainous peatlands. Using high frequency in situ instrumentation, this study shows the annual quantity of aquatic organic carbon exported from a montane peatland in the French Pyrenees is in the same range as Northern lowland peatlands. These highly variable exports mainly occur during high discharge events due to snowmelt or rainfalls. Despite its restricted area, this montane peatland is the main contributor of aquatic organic carbon in the watershed. Peatlands influence headwater chemistry and further study must be conducted to monitor the evolution of these mountainous carbon stocks.

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“…Permafrost soils in general could become carbon sources with warming through greater aerobic (CO 2 ) and anaerobic (CH 4 ) decomposition rates (Natali et al, ; Schuur et al, ). However, longer, warmer growing seasons and changes in Arctic precipitation regimes (Bintanja & Selten, ; Kattsov et al, ; Kopec et al, ) may stimulate carbon capture through enhanced plant productivity in peatlands and the transition of minerotrophic wetlands into organic peatlands (Charman et al, , ; Gallego‐Sala et al, ; Morris et al, ). Recent evidence shows an inconsistent response of Arctic and sub‐Arctic peatlands to warming in terms of carbon accumulation (Zhang, Gallego‐Sala, et al, ).…”

Section: Introductionmentioning

confidence: 99%

Pathways for Ecological Change in Canadian High Arctic Wetlands Under Rapid Twentieth Century Warming

Sim

Swindles

Morris

et al. 2019

Geophysical Research Letters

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We use paleoecological techniques to investigate how Canadian High Arctic wetlands responded to a mid‐twentieth century increase in growing degree days. We observe an increase in wetness, moss diversity, and carbon accumulation in a polygon mire trough, likely related to ice wedge thaw. Contrastingly, the raised center of the polygon mire showed no clear response. Wet and dry indicator testate amoebae increased concomitantly in a valley fen, possibly relating to greater inundation from snowmelt followed by increasing evapotranspiration. This occurred alongside the appearance of generalist hummock mosses. A coastal fen underwent a shift from sedge to shrub dominance. The valley and coastal fens transitioned from minerogenic to organic‐rich wetlands prior to the growing degree days increase. A subsequent shift to moss dominance in the coastal fen may relate to intensive grazing from Arctic geese. Our findings highlight the complex response of Arctic wetlands to warming and have implications for understanding their future carbon sink potential.

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Global peatland initiation driven by regionally asynchronous warming

Cited by 104 publications

References 38 publications

Modelling past and future peatland carbon dynamics across the pan‐Arctic

Modelling past and future peatland carbon dynamics across the pan‐Arctic

Peatland Contribution to Stream Organic Carbon Exports From a Montane Watershed

Pathways for Ecological Change in Canadian High Arctic Wetlands Under Rapid Twentieth Century Warming

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