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Atmospheric methane
About: Atmospheric methane is a research topic. Over the lifetime, 2034 publications have been published within this topic receiving 119616 citations.
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TL;DR: In this paper, the authors used atmospheric methane observations from the GOSAT satellite to evaluate methane wetland emission estimates and concluded that the inability of land surface models to increase wetland extent through overbank inundation is the primary cause of these observed discrepancies and can lead to under-estimation of methane fluxes by as much as 50% (5.3-11.8
55 citations
TL;DR: Modelling of a biotrickling filtration system composed of methane-consuming bacteria, i.e., methanotrophs, to assess the utility of these systems in removing methane from the atmosphere indicates that methane removal is ineffective using these meethanotrophic biofilters.
Abstract: Methane is a potent greenhouse gas with a global warming potential ~23 times that of carbon dioxide Here, we describe the modeling of a biotrickling filtration system composed of methane-consuming bacteria, ie, methanotrophs, to assess the utility of these systems in removing methane from the atmosphere Model results indicate that assuming the global average atmospheric concentration of methane, 17 ppmv, methane removal is ineffective using these methanotrophic biofilters as the methane concentration is too low to enable cell survival If the concentration is increased to 500–6,000 ppmv, however, similar to that found above landfills and in concentrated animal feeding operations (factory farms), 498–357 tons of methane can be removed per biofilter per year assuming biotrickling filters of typical size (366 m in diameter and 115 m in height) Using reported ranges of capital, operational, and maintenance costs, the cost of the equivalent ton of CO2 removal using these systems is $90–$910 ($2,070–$20,900 per ton of methane), depending on the influent concentration of methane and if heating is required The use of methanotrophic biofilters for controlling methane emissions is technically feasible and, provided that either the costs of biofilter construction and operation are reduced or the value of CO2 credits is increased, can also be economically attractive
55 citations
TL;DR: A biogeochemical model is used to simulate the response of early atmospheric O2 and CH4 to changes in marine AOM as sulphate levels increased and shows that methane levels collapse prior to any significant rise in O2, but counter-intuitively, methane re-rises after O2 rises to higher levels when AOM is included.
Abstract: In modern marine sediments, the anoxic decomposition of organic matter generates a significant flux of methane that is oxidized microbially with sulphate under the seafloor and never reaches the atmosphere. In contrast, prior to ca 2.4 Gyr ago, the ocean had little sulphate to support anaerobic oxidation of methane (AOM) and the ocean should have been an important methane source. As atmospheric O2 and seawater sulphate levels rose on the early Earth, AOM would have increasingly throttled the release of methane. We use a biogeochemical model to simulate the response of early atmospheric O2 and CH4 to changes in marine AOM as sulphate levels increased. Semi-empirical relationships are used to parameterize global AOM rates and the evolution of sulphate levels. Despite broad uncertainties in these relationships, atmospheric O2 concentrations generally rise more rapidly and to higher levels (of order approx. 10 K3 bar versus approx. 10 K4 bar) as a result of including AOM in the model. Methane levels collapse prior to any significant rise in O2, but counter-intuitively, methane re-rises after O2 rises to higher levels when AOM is included. As O2 concentrations increase, shielding of the troposphere by stratospheric ozone slows the effective reaction rate between oxygen and methane. This effect dominates over the decrease in the methane source associated with AOM. Thus, even with the inclusion of AOM, the simulated Late Palaeoproterozoic atmosphere has a climatologically significant level of methane of approximately 50 ppmv.
55 citations
TL;DR: The observed interhemispheric gradient is consistent with this lifetime and preferential release of methane in the northern hemisphere and Measurements taken in the Amazon basin region indicate the presence of a substantial source of gas in that area.
Abstract: The ground level concentrations of methane in the atmosphere have been measured to be in the range from 1.45 to 1.62 parts per million by volume (ppmv) of dry air in remote locations between 62°N and 54°S latitudes during the time period from November 1977 to July 1979. The average (±rms) concentration for the northern hemisphere was 1.57 ± 0.02 ppmv in January 1978 and 1.59 ± 0.02 in July 1979. The average concentration in the southern hemisphere was lower—1.47 ± 0.02 in January 1978 and 1.51 ± 0.01 in July 1979. The ratio of concentrations between the two hemispheres was 1.068 ± 0.016 in January 1978 and 1.055 ± 0.013 in July 1979, for an average of 1.06 ± 0.01. The higher concentrations in the northern hemisphere require either that the sources of methane lie preferentially in the northern hemisphere or that the removal processes operate more rapidly in the southern hemisphere or both. The primary removal process for CH4 is reaction with tropospheric OH radicals and its estimated atmospheric lifetime is 10.5 ± 1.8 yr. The observed interhemispheric gradient is consistent with this lifetime and preferential release of methane in the northern hemisphere. Measurements taken in the Amazon basin region indicate the presence of a substantial source of methane in that area.
55 citations