Global Methane Budget 2000–2020

Published: June 6, 2024

Abstract. Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Emissions atmospheric concentrations of CH4 continue increase, maintaining as second most human-influenced greenhouse gas in terms forcing after carbon dioxide (CO2). The relative importance compared CO2 temperature change related its shorter lifetime, stronger radiative effect, acceleration growth rate over past decade, causes which are still debated. Two major challenges reducing uncertainties factors explaining well-observed arise from diverse, geographically overlapping sources uncertain magnitude temporal destruction by short-lived highly variable hydroxyl radicals (OH). To address these challenges, we have established a consortium multi-disciplinary scientists under umbrella Global Carbon Project improve, synthesise update regularly stimulate new research on cycle. Following Saunois et al. (2016, 2020), present here third version living review paper dedicated decadal budget, integrating results top-down emission estimates (based in-situ observing satellite (GOSAT) observations an ensemble inverse-model results) bottom-up process-based models estimating land-surface emissions chemistry, inventories anthropogenic emissions, data-driven extrapolations). We recent 2010–2019 calendar decade (the latest period full datasets available), previous 2000–2009 year 2020. revision this edition benefits progress inland freshwater with better accounting lakes ponds, reservoirs, streams rivers. This also reduces double across wetland and, first time, includes estimate potential that exists (average 23 Tg yr-1). Bottom-up approaches show combined average 248 [159–369] yr-1 decade. Natural fluxes perturbed human activities through climate, eutrophication, land use. In estimate, component contributing emissions. Newly available gridded products allowed us derive almost complete latitudinal regional based approaches. For estimated inversions (top-down) be 575 (range 553–586, corresponding minimum maximum model ensemble). Of amount, 369 or ~65 % attributed direct fossil, agriculture waste biomass burning 350–391 63–68 %). period, give slightly lower total than 2010–2019, 32 9–40). Since 2012, trends been tracking scenarios assume no minimal mitigation policies proposed Intergovernmental Panel Climate Change (shared socio-economic SSP5 SSP3). methods suggest 16 (94 yr-1) larger (669 yr-1, range 512–849) inversion period. discrepancy between budgets has greatly reduced differences (167 156 respectively), time uncertainty overlap. distribution inversion-based indicates predominance tropical southern hemisphere (~65 <30° N) mid (30° N–60° N, ~30 emissions) high-northern latitudes (60° N–90° ~4 emissions). similar though contributions latitudes, smaller tropics inversions. Although bottom-up, source attributable natural especially those wetlands freshwaters. identify five priorities improving budget: i) producing global, high-resolution map water-saturated soils inundated areas emitting robust classification different types ecosystems; ii) further development inland-water emissions; iii) intensification at local (e.g., FLUXNET-CH4 measurements, urban-scale monitoring, imagery pointing capabilities) scales (surface networks remote sensing measurements satellites) constrain both inversions; iv) improvements transport representation photochemical sinks inversions, v) integration 3D variational systems using isotopic and/or co-emitted species such ethane well information super-emitters detected (mainly oil sector but coal, landfills) improve partitioning. data presented can downloaded https://doi.org/10.18160/GKQ9-2RHT (Martinez al., 2024).

Language: Английский

---

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

---

Practical Guide to Measuring Wetland Carbon Pools and Fluxes

Wetlands, Journal Year: 2023, Volume and Issue: 43(8)

Published: Nov. 28, 2023

Abstract Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, dioxide and methane emissions, aquatic C fluxes. However, underlying biogeochemical processes that affect wetland pools fluxes are complex dynamic, making measurements challenging. Over decades research, many observational, experimental, analytical approaches been developed to understand quantify C. Sampling range in their representation from short long timeframes local landscape spatial scales. This review summarizes common cutting-edge methodological for quantifying We first define each major provide rationale importance dynamics. For approach, we clarify what component is measured its temporal representativeness constraints. describe practical considerations such as where when an approach typically used, who can conduct (expertise, training requirements), how conducted, including equipment complexity costs. Finally, key covariates ancillary enhance interpretation findings facilitate model development. The protocols measure soil, water, vegetation, gases also relevant related disciplines ecology. Improved quality consistency data collection reporting across studies will help reduce uncertainties develop management strategies use wetlands nature-based climate solutions.

Language: Английский

---

Upscaling Wetland Methane Emissions From the FLUXNET‐CH4 Eddy Covariance Network (UpCH4 v1.0): Model Development, Network Assessment, and Budget Comparison

AGU Advances, Journal Year: 2023, Volume and Issue: 4(5)

Published: Sept. 6, 2023

Abstract Wetlands are responsible for 20%–31% of global methane (CH 4 ) emissions and account a large source uncertainty in the CH budget. Data‐driven upscaling fluxes from eddy covariance measurements can provide new independent bottom‐up estimates wetland emissions. Here, we develop six‐predictor random forest model (UpCH4), trained on 119 site‐years flux data 43 freshwater sites FLUXNET‐CH4 Community Product. Network patterns site‐level annual means mean seasonal cycles were reproduced accurately tundra, boreal, temperate regions (Nash‐Sutcliffe Efficiency ∼0.52–0.63 0.53). UpCH4 estimated 146 ± TgCH y −1 2001–2018 which agrees closely with current land surface models (102–181 overlaps top‐down atmospheric inversion (155–200 ). However, diverged both types spatial pattern dynamics tropical We conclude that has potential to produce realistic extra‐tropical will improve more data. To reduce upscaled estimates, researchers could prioritize along humid‐to‐arid climate gradients, major rainforest basins (Congo, Amazon, SE Asia), into monsoon (Bangladesh India) savannah (African Sahel) be paired improved knowledge extent these regions. The monthly products gridded at 0.25° available via ORNL DAAC ( https://doi.org/10.3334/ORNLDAAC/2253

Language: Английский

---

Factors Regulating the Potential for Freshwater Mineral Soil Wetlands to Function as Natural Climate Solutions

Wetlands, Journal Year: 2025, Volume and Issue: 45(1)

Published: Jan. 1, 2025

There are increasing global efforts and initiatives aiming to tackle climate change mitigate its impacts via natural solutions (NCS). Wetlands have been considered effective NCS given their capacity sequester retain atmospheric carbon dioxide (CO

Language: Английский

---

Air temperature and precipitation constraining the modelled wetland methane emissions in a boreal region in northern Europe

Biogeosciences, Journal Year: 2025, Volume and Issue: 22(1), P. 323 - 340

Published: Jan. 16, 2025

Abstract. Wetland methane responses to temperature and precipitation are studied in a boreal wetland-rich region northern Europe using ecosystem process models. Six models (JSBACH-HIMMELI, LPX-Bern, LPJ-GUESS, JULES, CLM4.5, CLM5) compared multi-model means of atmospheric inversions from the Global Carbon Project upscaled eddy covariance flux results for their seasonal cycles regional fluxes. Two with contrasting response patterns, LPX-Bern JSBACH-HIMMELI, used as priors Tracker Europe–CH4 (CTE-CH4) order find out how assimilation concentration data changes estimates this alters interpretation precipitation. Inversion moves wetland emissions both towards co-limitation by Between 2000 2018, periods high and/or often resulted increased emissions. However, dry summer 2018 did not result despite temperatures. The show strong (51 %–91 % variance explained both). month highest varies May September among means, inversions, observations agree on maximum co-limited setup different emission components (peatland emissions, mineral land fluxes) has an important role building up patterns. Considering significant differences models, it is essential pay more attention representation wet soils periodic flooding which contribute seasonality magnitude realistic dependence peat soil fluxes also important. Furthermore, use process-based descriptions simulate climate drivers.

Language: Английский

---

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

---

Variable rate precision application of feedlot cattle manure mitigates soil greenhouse gas emissions

Geoderma, Journal Year: 2025, Volume and Issue: 454, P. 117172 - 117172

Published: Jan. 22, 2025

Language: Английский

---

Drivers of Soil Carbon Variability in North America’s Prairie Pothole Wetlands: A Review

Wetlands, Journal Year: 2025, Volume and Issue: 45(1)

Published: Jan. 1, 2025

Language: Английский

---

Exploring environmental and meteorological factors influencing greenhouse gas emissions on major urbanized cities in Bangladesh

Urban Climate, Journal Year: 2025, Volume and Issue: 60, P. 102369 - 102369

Published: March 1, 2025

Language: Английский

---