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

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Notable shifts beyond pre-industrial streamflow and soil moisture conditions transgress the planetary boundary for freshwater change

Nature Water, Journal Year: 2024, Volume and Issue: 2(3), P. 262 - 273

Published: March 4, 2024

Abstract Human actions compromise the many life-supporting functions provided by freshwater cycle. Yet, scientific understanding of anthropogenic change and its long-term evolution is limited. Here, using a multi-model ensemble global hydrological models, we estimate how, over 145-year industrial period (1861–2005), streamflow soil moisture have deviated from pre-industrial baseline conditions (defined 5th–95th percentiles, at 0.5° grid level monthly timestep 1661–1860). Comparing two periods, find an increased frequency local deviations on ~45% land area, mainly in regions under heavy direct or indirect human pressures. To humanity’s aggregate impact these important elements cycle, present deviation occurrence regional to scales. Annually, now occur 18.2% 15.8% respectively, which 8.0 4.7 percentage points beyond ~3 point wide variability envelope. Our results signify substantial shift reference persistently increasing change. This indicates transgression new planetary boundary for change, defined quantified our approach, calling urgent reduce disturbance

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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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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Tracing sources of atmospheric methane using clumped isotopes

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(47)

Published: Nov. 13, 2023

We apply a recently developed measurement technique for methane (CH 4 ) isotopologues * (isotopic variants of CH — 13 , 12 3 D, and 2 D to identify contributions the atmospheric burden from fossil fuel microbial sources. The aim this study is constrain factors that ultimately control concentration potent greenhouse gas on global, regional, local levels. While predictions have been modeled, we present direct measurements point different composition flux with less clumping (greater deficits relative stochastic) in both than had previously assigned. These differences make isotopologue data sufficiently sensitive variations fluxes distinguish between emissions scenarios such as those generated by versions EDGAR (the Emissions Database Global Atmospheric Research), even when existing constraints profile well traditional isotopes are kept constant.

Language: Английский

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Methane emissions decreased in fossil fuel exploitation and sustainably increased in microbial source sectors during 1990–2020

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: April 17, 2024

Abstract Methane (CH 4 ) emission reduction to limit warming 1.5 °C can be tracked by analyzing CH concentration and its isotopic composition ( δ 13 C, D) simultaneously. Based on reconstructions of the temporal trends, latitudinal, vertical gradient C from 1985 2020 using an atmospheric chemistry transport model, we show (1) reductions oil gas exploitation (ONG) since 1990s stabilized growth rate in late early 2000s, (2) emissions farmed animals, waste management, coal mining contributed increase 2006. Our findings support neither increasing ONG reported EDGARv6 inventory during 1990–2020 nor large unconventional GAINSv4 Total fossil fuel remained stable 2000 2020, most likely because decrease some regions offset China.

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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Soil CO2 and CH4 response to experimental warming under various tree species compositions in a temperate harwood forest

Discover Soil., Journal Year: 2025, Volume and Issue: 2(1)

Published: March 11, 2025

Under climate change, some forest ecosystems appear to be transitioning into net source of carbon dioxide (CO2), raising questions about the future role soil respiration rate (Rs), which depends on hydroclimatic conditions. Conversely, well-drained soils could become more significant sinks methane (CH4) under warming. The main objective this study was assess effects artificial warming Rs and CH4 fluxes in a sugar maple at northern limit Quebec temperate deciduous forests eastern Canada, evaluate effect species composition response We measured during snow-free period 2021 2022 32 plots distributed across three types, half were artificially heated by approximately 2 °C with heating cables. Forest very consistent sink for it did not respond nor sensitive variations moisture, ionic activity solution types. However, we observed an increase plots, but only up threshold 15 °C, beyond started slow down respect control plots. also weakening exponential relationship between temperature threshold. This trend varied hardwood-beech stands being than mixedwoods other hardwoods. greater resulted downshift Rs, starting from colder threshold, around 10–12 °C. highlights potential plateauing despite rising temperature, least Canada's forest, vary one type another.

Language: Английский

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In search of better models for explaining atmospheric methane accumulation

Animal Frontiers, Journal Year: 2025, Volume and Issue: 15(1), P. 34 - 42

Published: Feb. 1, 2025

Language: Английский

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Increased methane emissions from oil and gas following the Soviet Union’s collapse

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(12)

Published: March 12, 2024

Global atmospheric methane concentrations rose by 10 to 15 ppb/y in the 1980s before abruptly slowing 2 8 early 1990s. This period 1990s is known as “methane slowdown” and has been attributed part collapse of former Soviet Union (USSR) December 1991, which may have decreased emissions from oil gas operations. Here, we develop a plume detection system based on probabilistic deep learning human-labeled training data. We use this method detect plumes Landsat 5 satellite observations over Turkmenistan 1986 2011. focus because economic data suggest it could account for half decline USSR. find an increase both frequency detections magnitude following estimate national loss rate infrastructure more than 10% at times, suggests socioeconomic turmoil led lack oversight widespread failure sector. Our finding increased USSR’s casts doubt long-standing hypothesis regarding slowdown, begging question: “what drove 1992 slowdown?”

Language: Английский

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