The isotopic composition of atmospheric methane

Quay, Paul D.; Stutsman, J.; Wilbur, David; Snover, A.K.; Dlugokencky, E. J.; Brown, Thomas A.

doi:10.1029/1998gb900006

Cited by 309 publications

(386 citation statements)

References 50 publications

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“…The same definition applies to CH 3 D, with the Vienna Standard Mean Ocean Water (VSMOW) R SMOW = 0.00015575. The isotopic composition of atmospheric methane is measured at a subset of surface stations (Quay et al, 1991(Quay et al, , 1999Lowe et al, 1994;Miller et al, 2002;Morimoto et al, 2006;Tyler et al, 2007). The mean atmospheric values are about −47 ‰ for δ 13 CH 4 and −86/−96 ‰ for δD(CH 4 ).…”

Section: Methane Isotope Observationsmentioning

confidence: 99%

The global methane budget 2000–2012

Saunois

Bousquet

Poulter

et al. 2016

Earth Syst. Sci. Data

945

733

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Abstract. The global methane (CH 4 ) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH 4 over the past decade. Emissions and concentrations of CH 4 are continuing to increase, making CH 4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH 4 sources that overlap geographically, and from the destruction of CH 4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (∼ biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). . Top-down inversions consistently infer lower emissions in China (∼ 58 Tg CH 4 yr −1 , range 51-72, −14 %) and higher emissions in Africa (86 Tg CH 4 yr −1 , range 73-108, +19 %) than bottom-up values used as prior estimates. Overall, uncertainties for anthropogenic emissions appear smaller than those from natural sources, and the uncertainties on source categories appear larger for top-down inversions than for bottom-up inventories and models.The most important source of uncertainty on the methane budget is attributable to emissions from wetland and other inland waters. We show that the wetland extent could contribute 30-40 % on the estimated range for wetland emissions. Other priorities for improving the methane budget include the following: (i) the development of process-based models for inland-water emissions, (ii) the intensification of methane observations at local scale (flux measurements) to constrain bottom-up land surface models, and at regional scale (surface networks and satellites) to constrain top-down inversions, (iii) improvements in the estimation of atmospheric loss by OH, and (iv) improvements of the transport models integrated in top-down inversions.

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Section: Methane Isotope Observationsmentioning

confidence: 99%

The global methane budget 2000–2012

Saunois

Bousquet

Poulter

et al. 2016

Earth Syst. Sci. Data

945

733

View full text Add to dashboard Cite

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“…Methane is the most abundant hydrocarbon and a major greenhouse gas (20 times more effective in its radiative forcing than CO 2 ) which plays an important role in the Earth's radiative balance (Quay et al, 1999). It is mainly produced by biological (anaerobic) activity and accumulated through geological processes such as gas hydrate or other CH 4 deposition pathways (Wuebbles and Hayhoe, 2002).…”

Section: Introductionmentioning

confidence: 99%

Methane production induced by dimethylsulfide in surface water of an upwelling ecosystem

Florez-Leiva¹,

Damm

Farı́as

2013

Progress in Oceanography

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a b s t r a c tCoastal upwelling ecosystems are areas of high productivity and strong outgassing, where most gases, such as N 2 O and CH 4 , are produced in subsurface waters by anaerobic metabolisms. We describe seasonal CH 4 variation as well as potential mechanisms producing CH 4 in surface waters of the central Chile upwelling ecosystem (36°S). Surface waters were always supersaturated in CH 4 (from 125% up to 550%), showing a clear seasonal signal triggered by wind driven upwelling processes (austral springsummer period), that matched with the periods of high chlorophyll-a and dimethylsulfoniopropionate (DMSP) levels. Methane cycling experiments, with/without the addition of dimethylsulfide (including 13 C-DMS) and acetylene (a nonspecific inhibitor of CH 4 oxidation) along with monthly measurements of CH 4 , DMSP and other oceanographic variables revealed that DMS can be a CH 4 precursor. Net CH 4 cycling rates (control) fluctuated between À0.64 and 1.44 nmol L À1 d À1 . After the addition of acetylene, CH 4 cycling rates almost duplicated relative to the control, suggesting a strong methanotrophic activity. With a spike of DMS, the net CH 4 cycling rate significantly increased relative to the acetylene and control treatment. Additionally, the d 13 C values of CH 4 at the end of the incubations (after addition of 13 C enriched-DMS) were changed, reaching À32‰ PDB compared to natural values between À44‰ and À46‰ PDB. These findings indicate that, in spite of the strong CH 4 consumption by methanotrophs, this upwelling area is an important source of CH 4 to the atmosphere. The effluxes are derived partially from in situ surface production and seem to be related to DMSP/DMS metabolism.

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“…[3] Stable isotopic signatures of OVOCs can provide information related to respective source and sink processes and the balance of source and sink strengths, i.e., their budgets, as demonstrated for other atmospheric trace gases such as methane (CH 4 ) [e.g., Quay et al, 1999] and chloromethane (CH 3 Cl) [Keppler et al, 2005]. However, consideration should be given to the faster isotope modifications of atmospheric OVOCs because of their shorter lifetimes than those of CH 4 and CH 3 Cl.…”

Section: Introductionmentioning

confidence: 99%

Carbon isotopic signatures of methanol and acetaldehyde emitted from biomass burning source

Yamada¹,

Hattori²,

Ito³

et al. 2009

Geophysical Research Letters

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[1] We present carbon isotopic signatures of methanol and acetaldehyde emitted from biomass burning sources using laboratory experiments. The respective d 13 C of methanol and acetaldehyde emitted from burning experiments of five plant materials (three C 3 and two C 4 plants) were À20-À46% and À11 -À25%. The variation in d 13 C of methanol depends on the d 13 C of the fuel biomass and burning conditions, but the variation in d 13 C of acetaldehyde depends on the d 13 C of fuel biomass and is independent of burning conditions. Combining these observations with previously reported global distributions of fire types, burning conditions, amounts of biomass burned, vegetation types, and emission factors, we estimated the global isotopic signature for biomass burning source as À33 ± 16% for methanol. Citation: Yamada, K., R. Hattori, Y. Ito, H. Shibata, and N. Yoshida (2009), Carbon isotopic signatures of methanol and acetaldehyde emitted from biomass burning source,

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The isotopic composition of atmospheric methane

Cited by 309 publications

References 50 publications

The global methane budget 2000–2012

The global methane budget 2000–2012

Methane production induced by dimethylsulfide in surface water of an upwelling ecosystem

Carbon isotopic signatures of methanol and acetaldehyde emitted from biomass burning source

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