Permafrost Carbon: Progress on Understanding Stocks and Fluxes Across Northern Terrestrial Ecosystems

Journal of Geophysical Research Biogeosciences, Journal Year: 2024, Volume and Issue: 129(3)

Published: Feb. 26, 2024

Abstract Significant progress in permafrost carbon science made over the past decades include identification of vast stocks, development new pan‐Arctic maps, an increase terrestrial measurement sites for CO 2 and methane fluxes, important factors affecting cycling, including vegetation changes, periods soil freezing thawing, wildfire, other disturbance events. Process‐based modeling studies now key elements cycling advances statistical inverse enhance understanding region C budgets. By combining existing data syntheses model outputs, is likely a wetland source small ecosystem sink with lower net uptake toward higher latitudes, excluding wildfire emissions. For 2002–2014, strongest was located western Canada (median: −52 g m −2 y −1 ) smallest sinks Alaska, Canadian tundra, Siberian tundra (medians: −5 to −9 ). Eurasian regions had largest median fluxes (16–18 CH 4 Quantifying regional scale balance remains challenging because high spatial temporal variability relatively low density observations. More accurate require: (a) better maps characterizing wetlands dynamics disturbances, abrupt thaw; (b) establishment year‐round flux underrepresented areas; (c) improved models that represent cycle dynamics, non‐growing season emissions effects.

Language: Английский

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The methane imperative

Frontiers in Science, Journal Year: 2024, Volume and Issue: 2

Published: July 30, 2024

Anthropogenic methane (CH 4 ) emissions increases from the period 1850–1900 until 2019 are responsible for around 65% as much warming carbon dioxide (CO 2 has caused to date, and large reductions in required limit global 1.5°C or 2°C. However, have been increasing rapidly since ~2006. This study shows that expected continue increase over remainder of 2020s if no greater action is taken atmospheric thus far outpacing projected growth rates. important implications reaching net zero CO targets: every 50 Mt CH sustained cuts envisioned under low-warming scenarios not realized would eliminate about 150 Gt remaining budget. Targeted therefore a critical component alongside decarbonization minimize warming. We describe additional linkages between mitigation options , especially via land use, well their respective climate impacts associated metrics. explain why target specifically neither necessary nor plausible. Analyses show where most feasible at national sectoral levels given limited resources, example, meet Global Methane Pledge target, but they also reveal uncertainties. Despite these uncertainties, many costs clearly low relative real-world financial instruments very compared with damage estimates, legally binding regulations pricing needed goals.

Language: Английский

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Ensemble estimates of global wetland methane emissions over 2000–2020

Biogeosciences, Journal Year: 2025, Volume and Issue: 22(1), P. 305 - 321

Published: Jan. 15, 2025

Abstract. Due to ongoing climate change, methane (CH4) emissions from vegetated wetlands are projected increase during the 21st century, challenging mitigation efforts aimed at limiting global warming. However, despite reports of rising emission trends, a comprehensive evaluation and attribution recent changes remains limited. Here we assessed wetland CH4 2000–2020 based on an ensemble 16 process-based models. Our results estimated average 158 ± 24 (mean 1σ) Tg yr−1 over total annual area 8.0 2.0×106 km2 for period 2010–2020, with 6–7 in 2010–2019 compared 2000–2009. The increases four latitudinal bands 90–30° S, 30° S–30° N, 30–60° 60–90° N were 0.1–0.2, 3.6–3.7, 1.8–2.4, 0.6–0.8 yr−1, respectively, 2 decades. modeled sensitivities temperature show reasonable consistency eddy-covariance-based measurements 34 sites. Rising was primary driver increase, while precipitation atmospheric CO2 concentrations played secondary roles high levels uncertainty. These suggest that change is driving increased direct sustained needed monitor developments.

Language: Английский

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The large role of declining atmospheric sulfate deposition and rising CO ₂ concentrations in stimulating future wetland CH ₄ emissions

Science Advances, Journal Year: 2025, Volume and Issue: 11(6)

Published: Feb. 5, 2025

Existing projections of wetland methane emissions usually neglect feedbacks from global biogeochemical cycles. Using data-driven approaches, we estimate 2000 to 2100, considering effects meteorological changes and atmospheric sulfate deposition CO 2 fertilization. In low-CO scenarios (1.5° 2°C warming pathways), the suppressive effect on largely diminishes by 2100 due clean air policies, with resulting emission increases (7 ± Tg a −1 ) being 35 22% total changes. mid-CO (2.4° 3.6°C modestly, fertilization contributes >30% increases. Across all scenarios, can stimulate 30 45% future rises. Under 1.5° pathways, will likely increase 20 34 representing 8 15% allowable space for anthropogenic emissions, factor not yet considered current assessments.

Language: Английский

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Advancements and opportunities to improve bottom-up estimates of global wetland methane emissions

Environmental Research Letters, Journal Year: 2025, Volume and Issue: 20(2), P. 023001 - 023001

Published: Jan. 22, 2025

Abstract Wetlands are the single largest natural source of atmospheric methane (CH 4 ), contributing approximately 30% total surface CH emissions, and they have been identified as uncertainty in global budget based on most recent Global Carbon Project report. High uncertainties bottom–up estimates wetland emissions pose significant challenges for accurately understanding their spatiotemporal variations, scientific community to monitor from space. In fact, there large disagreements between versus top–down inferred inversion concentrations. To address these critical gaps, we review development, validation, applications well how used inversions. These estimates, using (1) empirical biogeochemical modeling (e.g. WetCHARTs: 125–208 TgCH yr −1 ); (2) process-based WETCHIMP: 190 ± 39 (3) data-driven machine learning approach UpCH4: 146 43 ). Bottom–up subject (∼80 Tg ranges different do not overlap, further amplifying overall when combining multiple data products. substantial highlight gaps our biogeochemistry inundation dynamics. Major tropical arctic complexes regional hotspots emissions. However, scarcity satellite over tropics northern high latitudes offer limited information inversions improve estimates. Recent advances measurements fluxes FLUXNET-CH ) across a wide range ecosystems including bogs, fens, marshes, forest swamps provide an unprecedented opportunity existing We suggest that continuous long-term at representative wetlands, fidelity mapping, combined with appropriate framework, will be needed significantly There is also pressing unmet need fine-resolution high-precision observations directed wetlands.

Language: Английский

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Recent increases in annual, seasonal, and extreme methane fluxes driven by changes in climate and vegetation in boreal and temperate wetland ecosystems

Global Change Biology, Journal Year: 2024, Volume and Issue: 30(1)

Published: Jan. 1, 2024

Abstract Climate warming is expected to increase global methane (CH 4 ) emissions from wetland ecosystems. Although in situ eddy covariance (EC) measurements at ecosystem scales can potentially detect CH flux changes, most EC systems have only a few years of data collected, so temporal trends remain uncertain. Here, we use established drivers hindcast changes fluxes (FCH since the early 1980s. We trained machine learning (ML) model on 22 [methane‐producing sites] wetland, upland, and lake sites FLUXNET‐CH database with least two full across temperate boreal biomes. The gradient boosting decision tree ML then hindcasted daily FCH over 1981–2018 using meteorological reanalysis data. found that, mainly driven by rising temperature, half ( n = 11) showed significant increases annual, seasonal, extreme , ca. 10% or higher fall 1981–1989 2010–2018. annual were during summer fall, particularly high‐CH ‐emitting fen dominated aerenchymatous plants. also that distribution days extremely high (defined according 95th percentile values reference period) become more frequent last four decades currently account for 10–40% total seasonal fluxes. share was greatest winter boreal/taiga spring sites, which highlights increasing importance non‐growing seasons budgets. Our results shed light effects climate wetlands, appears be extending emission emissions.

Language: Английский

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Interpreting the Seasonality of Atmospheric Methane

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(10)

Published: May 15, 2024

Abstract Surface and satellite observations of atmospheric methane show smooth seasonal behavior in the Southern Hemisphere driven by loss from hydroxyl (OH) radical. However, Northern a sharp mid‐summer increase that is asymmetric with not captured default configuration GEOS‐Chem chemical transport model. Using an ensemble 22 OH model estimates 24 wetland emission inventories GEOS‐Chem, we magnitude, latitudinal distribution, seasonality emissions are critical for reproducing observed hemisphere, interhemispheric ratio playing lesser role. Reproducing requires inventory ∼80 Tg −1 poleward 10°N including significant South Asia, August peak boreal persisting into autumn. In our 24‐member ensemble, only LPJ‐wsl MERRA‐2 has these attributes.

Language: Английский

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Three Decades of Wetland Methane Surface Flux Modeling by Earth System Models‐Advances, Applications, and Challenges

Journal of Geophysical Research Biogeosciences, Journal Year: 2024, Volume and Issue: 129(3)

Published: March 1, 2024

Abstract Earth System Models (ESMs) simulate the exchange of mass and energy between land surface atmosphere, with a key focus on modeling natural greenhouse gas feedbacks. Methane is second most important after carbon dioxide. There are growing concerns over rapidly increasing methane concentration in underscoring need for accurate global its emissions using ESMs. Of multitude sources globally, wetlands largest emitters methane, leading to significant efforts targeting their representation ESMs special emissions. In this review, we first provide historical overview including wetland‐methane components how approaches have evolved time. Second, discuss recent advancements that show promise improvements predictions, namely coupling atmospheric modules ESMs, microtopography transport mechanisms, resolution microbial processes at different spatial‐temporal scales, improved mapping wetland area extent across types. Third, shed light challenges hindering estimations emissions, as shown by consistent discrepancy bottom‐up top‐down models' predictions. Finally, emphasize more detailed biogeochemistry dynamic hydrology while resolving within‐wetland vegetation heterogeneity should improve model especially when coupled expanding ground‐based measurement networks high‐resolution remote sensing methane‐relevant variables, such water elevation, table depth, concentration.

Language: Английский

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Ensemble estimates of global wetland methane emissions over 2000–2020

Published: June 11, 2024

Abstract. Due to ongoing climate change, methane (CH4) emissions from vegetated wetlands are projected increase during the 21st century, challenging mitigation efforts aimed at limiting global warming. However, despite reports of rising emission trends, a comprehensive evaluation and attribution recent changes is still lacking. Here we assessed wetland CH4 2000 2020 based on an ensemble sixteen process-based models. Our results estimated average 158±24 (mean ± 1σ) Tg yr-1 for period 2010–2020, with decadal 6–7 compared decade 2000–2009. The increases in four latitudinal bands 90° S–30° S, 30° N, N–60° 60° N–90° N were 0.1–0.2 yr-1, 3.6–3.7 1.8–2.4 0.6–0.8 respectively, over two decades. modeled sensitivities temperature show reasonable consistency eddy covariance-based measurements 34 sites. Rising was primary driver increase, while precipitation atmospheric CO2 concentrations played secondary roles high levels uncertainty. These suggest change driving increased that direct sustained needed monitor developments.

Language: Английский

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Studies of Arctic–boreal ecosystem function and biogeochemical cycles in the ArCS II terrestrial program

Polar Science, Journal Year: 2025, Volume and Issue: unknown, P. 101164 - 101164

Published: Jan. 1, 2025

Language: Английский

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