Permafrost carbon cycle and its dynamics on the Tibetan Plateau

Science China Life Sciences, Год журнала: 2024, Номер 67(9), С. 1833 - 1848

Опубликована: Июнь 26, 2024

Язык: Английский

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Inland water greenhouse gas emissions offset the terrestrial carbon sink in the northern cryosphere

Science Advances, Год журнала: 2024, Номер 10(39)

Опубликована: Сен. 27, 2024

Climate-sensitive northern cryosphere inland waters emit greenhouse gases (GHGs) into the atmosphere, yet their total emissions remain poorly constrained. We present a data-driven synthesis of GHG from considering water body types, zones, and seasonality. find that annual are dominated by carbon dioxide ( 1149.2 1004.8 1307.5 teragrams CO 2 ; median Q 1 3 ) methane 14.2 10.1 18.5 CH 4 ), while nitrous oxide emission 5.4 − 1.4 12.2 gigagrams N O) is minor. The –equivalent (CO e) 1.5 1.3 1.8 or 2.3 2.8 petagrams e using 100- 20-year global warming potentials, respectively. Rivers 64% more GHGs than lakes, despite having only one-fifth surface area. continuous permafrost zone contributed half emissions. Annual exceed region’s terrestrial net ecosystem exchange, highlighting important role in cryospheric land-aquatic continuum under climate.

Язык: Английский

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Impacts of benchmarking choices on inferred model skill of the Arctic–Boreal terrestrial carbon cycle

Environmental Research Ecology, Год журнала: 2025, Номер 4(1), С. 015007 - 015007

Опубликована: Фев. 3, 2025

Abstract Land surface models require continuous validation against observations to improve and reduce simulation uncertainty. However, inferred model performance can be heavily influenced by subjective choices made in the selection application of observational data products. A key area often misrepresented is Arctic–Boreal region, which a potential tipping point region Earth’s climate system due large permafrost carbon stocks that are vulnerable release with warming. We use International Model Benchmarking (ILAMB) framework evaluate how skill TRENDY-v9 varies based on choice observational-based benchmark benchmarks applied evaluation. This analysis uses global datasets integrated into ILAMB new, regionally-specific products from Vulnerability Experiment. Our results cover overall time period 1979–2019 show scores vary substantially depending product applied, higher indicating better observations. The lowest occur when benchmarked regional, compared global, datasets. also observed modeled functional relationships between ecosystem respiration air temperature gross primary production precipitation. Here, we find magnitude shape responses strongly impacted dataset approach used construct relationship benchmark. These suggest evaluation studies could conclude false sense if only using single or not applying regional performing analysis. Collectively, our findings highlight influence benchmarking need for guidelines assessing skill.

Язык: Английский

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The land–ocean Arctic carbon cycle

Nature Reviews Earth & Environment, Год журнала: 2025, Номер 6(2), С. 86 - 105

Опубликована: Фев. 1, 2025

Язык: Английский

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InSAR-derived seasonal subsidence reflects spatial soil moisture patterns in Arctic lowland permafrost regions

˜The œcryosphere, Год журнала: 2025, Номер 19(3), С. 1103 - 1133

Опубликована: Март 11, 2025

Abstract. The identification of spatial soil moisture patterns is high importance for various applications in high-latitude permafrost regions but challenging with common remote sensing approaches due to landscape heterogeneity. Seasonal thawing and freezing near-surface lead subsidence–heave cycles the presence ground ice, which exhibit magnitudes typically less than 10 cm. Our investigations document higher Sentinel-1 InSAR (interferometric synthetic aperture radar) seasonal subsidence rates (calculated per degree days – a measure heating) locations compared drier ones. Based on this, we demonstrate that relationship signals can be interpreted assess variations moisture. A range challenges, however, need addressed. We discuss implications using different sources temperature data deriving results. Atmospheric effects must considered, as simple filtering suppress large-scale permafrost-related underestimation displacement values, making Generic Correction Online Service (GACOS)-corrected results preferable tested sites. rate retrieval considers these aspects provides valuable tool distinguishing between wet dry features, relevant degradation monitoring Arctic lowland regions. Spatial resolution constraints, remain smaller typical features drive versus conditions such high- low-centred polygons.

Язык: Английский

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Permafrost Region Greenhouse Gas Budgets Suggest a Weak CO₂ Sink and CH₄ and N₂O Sources, But Magnitudes Differ Between Top‐Down and Bottom‐Up Methods

Global Biogeochemical Cycles, Год журнала: 2024, Номер 38(10)

Опубликована: Окт. 1, 2024

Abstract Large stocks of soil carbon (C) and nitrogen (N) in northern permafrost soils are vulnerable to remobilization under climate change. However, there large uncertainties present‐day greenhouse gas (GHG) budgets. We compare bottom‐up (data‐driven upscaling process‐based models) top‐down (atmospheric inversion budgets dioxide (CO 2 ), methane (CH 4 ) nitrous oxide (N O) as well lateral fluxes C N across the region over 2000–2020. Bottom‐up approaches estimate higher land‐to‐atmosphere for all GHGs. Both show a sink CO natural ecosystems (bottom‐up: −29 (−709, 455), top‐down: −587 (−862, −312) Tg ‐C yr −1 sources CH 38 (22, 53), 15 (11, 18) O 0.7 (0.1, 1.3), 0.09 (−0.19, 0.37) O‐N ). The combined global warming potential three gases (GWP‐100) cannot be distinguished from neutral. Over shorter timescales (GWP‐20), is net GHG source because dominates total forcing. Boreal forests wetlands largely offset by fires inland water emissions waters, with smaller contribution emissions. Priorities future research include representation waters models compilation process‐model ensembles O. Discrepancies between methods call analyses how prior flux impact budgets, more well‐distributed situ measurements improved resolution techniques.

Язык: Английский

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Changing climatic controls on the greenhouse gas balance of thermokarst bogs during succession after permafrost thaw

Global Change Biology, Год журнала: 2024, Номер 30(7)

Опубликована: Июль 1, 2024

Abstract Permafrost thaw in northern peatlands causes collapse of permafrost peat plateaus and thermokarst bog development, with potential impacts on atmospheric greenhouse gas exchange. Here, we measured methane carbon dioxide fluxes over 3 years (including winters) using static chambers along two transects northwestern Canada, spanning young (~30 since thaw), intermediate mature bogs (~200 thaw). Young were wetter, warmer had more hydrophilic vegetation than bogs. Methane emissions increased wetness soil temperature (40 cm depth) modelled annual estimates greatest the during warmest year lowest coolest (21 7 g C‐CH 4 m −2 −1 , respectively). The dominant control net ecosystem exchange (NEE) (between +20 −54 C‐CO 2 ) was (5 cm), causing CO loss due to higher respiration (ER) years. In contrast, controlled NEE +55 −95 ), where periodic inundation at beginning growing season caused greater reduction gross primary productivity ER leading loss. Winter (November–April) represented 16% 38% CH emissions. Our study found be close neutral rules out large losses under current conditions. However, high after a positive radiative forcing effect. While wet conditions favouring only persist for initial period, showed that continued climate warming ER, thus, from can cause which would last centuries thaw.

Язык: Английский

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Strong legacies of emerging trends in winter precipitation on the carbon-climate feedback from Arctic tundra

The Science of The Total Environment, Год журнала: 2025, Номер 962, С. 178246 - 178246

Опубликована: Янв. 1, 2025

Changes in winter precipitation accompanying emerging climate trends lead to a major carbon-climate feedback from Arctic tundra. However, the mechanisms driving direction, magnitude, and form (CO2 CH4) of C fluxes derived forcing (i.e. GWP, global warming potential) tundra under future scenarios remain unresolved. Here, we investigated impacts 18 years shallow (SS, -15-30 %) deeper (IS, +20-45 %; DS, +70-100 snow depth on ecosystem GWP moist acidic over growing season. The response accumulation was markedly non-linear. Both shallow- deeper- decreased CO2 emissions relative ambient (AS), ultimately reducing losses Gross primary productivity (GPP) increased with moderate increases further closely following transitions shrub abundance. Photosynthetic uptake, however, tightly regulated by canopy structure plant respiration (Raut) GPP ratio highly conserved despite substantial transformations community across treatments revealing prominent role heterotrophic (Rhet) net exchange. Consistently, gains responded constraints Rhet temperature limitation within colder soils at SS, snow- thaw-induced soil-water content (SWC) that promoted anaerobic decomposition dampened sensitivity IS DS. Greater CH4 wetter soils, potential (GWP) DS decreases losses. Overall, our findings indicate tussock reduce season but also significantly contribute precipitation.

Язык: Английский

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Scaling Arctic landscape and permafrost features improves active layer depth modeling

Environmental Research Ecology, Год журнала: 2025, Номер 4(1), С. 015001 - 015001

Опубликована: Янв. 20, 2025

Abstract Tundra ecosystems in the Arctic store up to 40% of global below-ground organic carbon but are exposed fastest climate warming on Earth. However, accurately monitoring landscape changes is challenging due complex interactions among permafrost, micro-topography, climate, vegetation, and disturbance. This complexity results high spatiotemporal variability permafrost distribution active layer depth (ALD). Moreover, these key tundra processes interact at different scales, an observational mismatch can limit our understanding intrinsic connections dynamics between above processes. Consequently, this could ability model anticipate how ALD will respond change disturbances across ecosystems. In paper, we studied fine-scale heterogeneity its with land surface characteristics spatial spectral scales using a combination ground, unoccupied aerial system, airborne, satellite observations. We showed that airborne sensors such as AVIRIS-NG medium-resolution Earth observation systems like Sentinel-2 capture average scale. found best scale for modeling heavily influenced by vegetation landform patterns occurring landscape. Landscapes characterized small-scale features polygon tussock require high-resolution observations disturbance patterns. Conversely, landscapes dominated water tracks shrubs, manifest larger indicate performance medium resolution (5 m), outperforming both higher (0.4 m) lower (10 models. transcends study show response may vary dominant ecosystem types, driven above- which happening. thus recommend tailoring based landforms distribution, thereby mitigating influences spatial-scale mismatches improving region.

Язык: Английский

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Dynamic soil columns simulate Arctic redox biogeochemistry and carbon release during changes in water saturation

Scientific Reports, Год журнала: 2025, Номер 15(1)

Опубликована: Янв. 24, 2025

Abstract Thawing Arctic permafrost can induce hydrologic change and alter redox conditions, shifting the balance of soil organic matter (SOM) decomposition. There remains uncertainty about how saturation transitions impact dissolved gas phase carbon fluxes, efforts to link hydrobiogeochemical processes ecosystem-scale models are limited. This study evaluates SOM decomposition tundra soils using column experiments, water chemistry measurements, microbial community analysis, a PFLOTRAN reactive transport model. Soil columns from thermokarst channel (TC) an upland (UC) were exposed cycles drainage, which controlled emissions. During saturation, outflow UC correlated with elevated reduced iron decreased pH; during dioxide fluxes 70% higher than TC fluxes. Intermittent methane release was observed for TC, consistent methanogen abundance. Slower drainage in more subtle biogeochemical changes. simulations captured experimental trends oxygen concentrations, contents. The model then used evaluate additional rates. emphasizes importance considering when evaluating simulating dynamic environments.

Язык: Английский

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