[1] Recent spectroscopic detections of CH4 in the atmosphere of Mars are the first definitive observations of an organic compound on that planet. The relatively short photochemical lifetime of CH4 ( 300 years) argues for a geologically young source. We demonstrate here that lowtemperature alteration of basaltic crust by carbon-bearing hydrothermal fluid can produce the required CH4 flux of 1 10...

Methane (CH4) emissions from animals represent a significant contribution to anthropogenically produced radiatively active trace gases. Global and national CH4 budgets currently use predictive models based on emission data from laboratory experiments to estimate the magnitude of the animal source. This paper presents a method for measuring CH4 from animals under undisturbed field conditions and...

[1] Anaerobic oxidation of methane (AOM) is a considerable sink for the greenhouse gas methane (CH4) in marine systems, but the importance of this process in terrestrial systems is less clear. Lowland boreal soils and wet tropical soils are two hot spots for CH4 cycling, yet AOM has been essentially uncharacterized in these systems. We investigated AOM in soils from sites in Alaska and Puerto R...

The trend and interannual variability of methane sources are derived from multi-annual simulations of tropospheric photochemistry using a 3-D global chemistrytransport model. Our semi-inverse analysis uses the fifteen years (1979–1993) re-analysis of ECMWF meteorological data and annually varying emissions including photochemistry, in conjunction with observed CH4 concentration distributions an...

Methane is the second most important long-lived greenhouse gas and plays a central role in the chemistry of the Earth’s atmosphere. Nonetheless there are significant uncertainties in its source budget. Analysis of the isotopic composition of atmospheric methane, including the doubly substituted species CH3D, offers new insight into the methane budget as the sources and sinks have distinct isoto...

Atmospheric methane (CH4) increased from ∼900 ppb (parts per billion, or nanomoles per mole of dry air) in 1900 to ∼1800 ppb in 2010 at a rate unprecedented in any observational records. However, the contributions of the various methane sources and sinks to the CH4 increase are poorly understood. Here we use initial emissions from bottom-up inventories for anthropogenic sources, emissions from ...

Methane is the second most important long-lived greenhouse gas and plays a central role in the chemistry of the Earth’s atmosphere. Nonetheless there are significant uncertainties in its source budget. Analysis of the isotopic composition of atmospheric methane, including the doubly substituted species CH3D, offers new insight into the methane budget as the sources and sinks have distinct isoto...

We determined methane (CH4) emissions from Alaska using airborne measurements from the Carbon Arctic Reservoirs Vulnerability Experiment (CARVE). Atmospheric sampling was conducted between May and September 2012 and analyzed using a customized version of the polar weather research and forecast model linked to a Lagrangian particle dispersion model (stochastic time-inverted Lagrangian transport ...

The near-infrared nadir spectra measured by SCIAMACHY on-board ENVISAT contain information on the vertical columns of important atmospheric trace gases such as carbon monoxide (CO), methane (CH4), and carbon dioxide (CO2). The scientific algorithm WFM-DOAS has been used to retrieve this information. For CH4 and CO2 also column averaged mixing ratios (XCH4 and XCO2) have been determined by simul...

1984 Methane (CH4) and ammonia (NH3) are emitted to the atmosphere during anaerobic processing of organic matter, and both gases have detrimental environmental eff ects. Methane conversion to biofuel production has been suggested to reduce CH4 emissions from animal manure processing systems. Th e purpose of this research is to evaluate the change in CH4 and NH3 emissions in an animal feeding op...