Revised methane emissions factors and spatially distributed annual carbon fluxes for global livestock

Wolf, Julie; Asrar, Ghassem; West, Tristram O.

doi:10.1186/s13021-017-0084-y

Cited by 157 publications

(123 citation statements)

References 48 publications

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“…Yacovitch et al (2015) For a contextualised UK comparison of instantaneous emissions, the fracking fluxes (from one sampling day) in figure 3 dwarf the maximum cattle emission flux (within uncertainty) of 3 g s −1 . The cattle fluxes are in broad agreement with inventory predictions (0.0042 g s −1 per animal) for enteric fermentation, from dairy cattle free to pasture in Western Europe (Wolf et al 2017). As the farm contained adult lactating cattle, young cattle and organic waste produced by the cattle, UAV sampling provides a unique opportunity to accurately quantify all methane emissions from the dairy farm, as a single facility.…”

Section: Flux Results and Discussionsupporting

confidence: 71%

Unmanned aerial vehicle observations of cold venting from exploratory hydraulic fracturing in the United Kingdom

Shah

Ricketts

Pitt

et al. 2020

Environ. Res. Commun.

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Unmanned aerial vehicle (UAV) surveys allow for rapid-response near-field sampling, downwind of emission sources, such as gas extraction sites, without the need for site access. UAVs can be used in emission source identification alongside instantaneous flux estimation. A UAV was used to sample downwind of the UK's first and only gas extraction site to use exploratory onshore horizontal hydraulic fracturing (fracking) of shale formations, in Little Plumpton, Lancashire. In-situ calibrated UAV methane mole fraction measurements were made from a neighbouring field on five sampling days between October 2018 and February 2019, during fracking, flow-back and flow testing. Methane emissions were identified on one of the five sampling days (14 January 2019), associated with known cold venting, following fluid unloading using a nitrogen lift. A near-field Gaussian plume inversion approach was used to calculate four instantaneous fluxes on this day (from four separate intermittent UAV flight surveys) with lower and upper uncertainty bounds of between 9-80 g s −1 , 23-106 g s −1 , 16-82 g s −1 and 34-156 g s −1 , respectively. The cold venting emissions observed on this single day were at least an order of magnitude higher than UAV methane fluxes calculated for nearby dairy farm buildings, also presented here. Identifying and quantifying these methane emission sources are important to improve the national emissions inventory and to regulate this developing UK industry.

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Section: Flux Results and Discussionsupporting

confidence: 71%

Unmanned aerial vehicle observations of cold venting from exploratory hydraulic fracturing in the United Kingdom

Shah

Ricketts

Pitt

et al. 2020

Environ. Res. Commun.

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“…The new ONG trends are 3.2 ± 1.3%/year and 4.8± 1.0%/year for SGP‐s and WKT‐s, respectively, which are within the uncertainty ranges of our previous estimates. This is expected because both sites are dominated by ONG emissions and non‐ONG emissions account for less than 15% of the CH 4 enhancements (Wolf et al, ).…”

Section: Trends In Ch4 and Ch4 Vertical Gradients (δCh4)mentioning

confidence: 99%

Long‐Term Measurements Show Little Evidence for Large Increases in Total U.S. Methane Emissions Over the Past Decade

Tans

Sweeney

et al. 2019

Geophysical Research Letters

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Recent studies show conflicting estimates of trends in methane (CH4) emissions from oil and natural gas (ONG) operations in the United States. We analyze atmospheric CH4 measurements from 20 North American sites in the National Oceanic and Atmospheric Administration Global Greenhouse Gas Reference Network and determined trends for 2006–2015. Using CH4 vertical gradients as an indicator of regional surface emissions, we find no significant increase in emissions at most sites and modest increases at three sites heavily influenced by ONG activities. Our estimated increases in North American ONG CH4 emissions (on average approximately 3.4 ± 1.4 %/year for 2006–2015, ±σ) are much smaller than estimates from some previous studies and below our detection threshold for total emissions increases at the east coast sites that are sensitive to U.S. outflows. We also find an increasing trend in ethane/methane emission ratios, which has resulted in major overestimation of oil and gas emissions trends in some previous studies.

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“…The atmospheric CH 4 growth rate is not exclusively a result of changes in wetland emissions, but rather due to a combined influence of anthropogenic and natural sources, and also due to a hydroxyl radical sink (Turner et al 2017, Rigby et al 2017. Recent studies have reported an increase in annual CH 4 emissions from global livestock (Wolf et al 2017) and an expansion of agricultural areas for rice paddies in southern Asia (Zhang et al 2017a), a region where precipitation has largely increased since 2007. Thus, we hypothesize that a combination of tropical wetlands and agricultural sources are likely responsible for the resumed growth rate of atmospheric CH 4 concentrations, which is consistent with the depletion in the global isotopic signature in 13 CH 4 (Schaefer et al 2016) and with regional measurements of 13 CH 4 in the tropics (Nisbet et al 2016).…”

Section: Relationship Between Wetland Ch 4 and Atmospheric Growth Ratementioning

confidence: 99%

Enhanced response of global wetland methane emissions to the 2015–2016 El Niño-Southern Oscillation event

Zhang

Zimmermann

Calle

et al. 2018

Environ. Res. Lett.

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Wetlands are thought to be the major contributor to interannual variability in the growth rate of atmospheric methane (CH4) with anomalies driven by the influence of the El Niño-Southern Oscillation (ENSO). Yet it remains unclear whether (i) the increase in total global CH4 emissions during El Niño versus La Niña events is from wetlands and (ii) how large the contribution of wetland CH4 emissions is to the interannual variability of atmospheric CH4. We used a terrestrial ecosystem model that includes permafrost and wetland dynamics to estimate CH4 emissions, forced by three separate meteorological reanalyses and one gridded observational climate dataset, to simulate the spatio-temporal dynamics of wetland CH4 emissions from 1980–2016. The simulations show that while wetland CH4 responds with negative annual anomalies during the El Niño events, the instantaneous growth rate of wetland CH4 emissions exhibits complex phase dynamics. We find that wetland CH4 instantaneous growth rates were declined at the onset of the 2015–2016 El Niño event but then increased to a record-high at later stages of the El Niño event (January through May 2016). We also find evidence for a step increase of CH4 emissions by 7.8±1.6 Tg CH4 yr−1 during 2007–2014 compared to the average of 2000–2006 from simulations using meteorological reanalyses, which is equivalent to a ~3.5 ppb yr−1 rise in CH4 concentrations. The step increase is mainly caused by the expansion of wetland area in the tropics (30°S–30°N) due to an enhancement of tropical precipitation as indicated by the suite of the meteorological reanalyses. Our study highlights the role of wetlands, and the complex temporal phasing with ENSO, in driving the variability and trends of atmospheric CH4 concentrations. In addition, the need to account for uncertainty in meteorological forcings is highlighted in addressing the interannual variability and decadal-scale trends of wetland CH4 fluxes.

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Revised methane emissions factors and spatially distributed annual carbon fluxes for global livestock

Cited by 157 publications

References 48 publications

Unmanned aerial vehicle observations of cold venting from exploratory hydraulic fracturing in the United Kingdom

Unmanned aerial vehicle observations of cold venting from exploratory hydraulic fracturing in the United Kingdom

Long‐Term Measurements Show Little Evidence for Large Increases in Total U.S. Methane Emissions Over the Past Decade

Enhanced response of global wetland methane emissions to the 2015–2016 El Niño-Southern Oscillation event

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