scholarly journals Stable isotopes provide revised global limits of aerobic methane emissions from plants

2007 ◽  
Vol 7 (1) ◽  
pp. 237-241 ◽  
Author(s):  
D. F. Ferretti ◽  
J. B. Miller ◽  
J. W. C. White ◽  
K. R. Lassey ◽  
D. C. Lowe ◽  
...  
Keyword(s):  
Methane Concentration ◽  
Ice Core ◽  
Stable Carbon Isotope ◽  
Atmospheric Methane ◽  
Stable Carbon ◽  
Terrestrial Plants ◽  
Unknown Mechanism ◽  
Stable Carbon Isotope Ratios ◽  
Annual Total ◽  
Plant Emissions

Abstract. Recently Keppler et al. (2006) discovered a surprising new source of methane – terrestrial plants under aerobic conditions, with an estimated global production of 62–236 Tg yr−1 by an unknown mechanism. This is ~10–40% of the annual total of methane entering the modern atmosphere and ~30–100% of annual methane entering the pre-industrial (0 to 1700 AD) atmosphere. Here we test this reported global production of methane from plants against ice core records of atmospheric methane concentration (CH4) and stable carbon isotope ratios (δ13CH4) over the last 2000 years. Our top-down approach determines that global plant emissions must be much lower than proposed by Keppler et al. (2006) during the last 2000 years and are likely to lie in the range 0–46 Tg yr−1 and 0–176 Tg yr−1 during the pre-industrial and modern eras, respectively.

scholarly journals Stable isotopes provide revised global limits of aerobic methane emissions from plants

2006 ◽  
Vol 6 (4) ◽  
pp. 5867-5875 ◽  
Author(s):  
D. F. Ferretti ◽  
J. B. Miller ◽  
J. W. C. White ◽  
K. R. Lassey ◽  
D. C. Lowe ◽  
...  
Keyword(s):  
Methane Concentration ◽  
Ice Core ◽  
Stable Carbon Isotope ◽  
Atmospheric Methane ◽  
Stable Carbon ◽  
Terrestrial Plants ◽  
Unknown Mechanism ◽  
Stable Carbon Isotope Ratios ◽  
Annual Total ◽  
Plant Emissions

Abstract. Recently Keppler et al. (2006) discovered a surprising new source of methane – terrestrial plants under aerobic conditions, with an estimated global production of 62–236 Tg yr−1 by an unknown mechanism. This is ~10–50% of the annual total of methane entering the modern atmosphere and ~30–100% of annual methane entering the pre-industrial (0 to 1700 AD) atmosphere. Here we test this reported global production of methane from plants against ice core records of atmospheric methane concentration (CH4) and stable carbon isotope ratios (δ13CH4) over the last 2000 years. Our top-down approach determines that global plant emissions must be much lower than proposed by Keppler et al. (2006) during the last 2000 years and are likely to lie in the range 0–46 Tg yr−1.

scholarly journals Enrichment in <sup>13</sup>C of atmospheric CH<sub>4</sub> during the Younger Dryas termination

2012 ◽  
Vol 8 (4) ◽  
pp. 1177-1197 ◽  
Author(s):  
J. R. Melton ◽  
H. Schaefer ◽  
M. J. Whiticar
Keyword(s):  
Mass Balance ◽  
Biomass Burning ◽  
Gas Hydrates ◽  
Stable Carbon Isotope ◽  
Younger Dryas ◽  
Carbon Isotope Ratio ◽  
Atmospheric Methane ◽  
Stable Carbon ◽  
Balance Test ◽  
Thermokarst Lakes

Abstract. The abrupt warming across the Younger Dryas termination (~11 600 yr before present) was marked by a large increase in the global atmospheric methane mixing ratio. The debate over sources responsible for the rise in methane centers on the roles of global wetlands, marine gas hydrates, and thermokarst lakes. We present a new, higher-precision methane stable carbon isotope ratio (δ13CH4) dataset from ice sampled at Påkitsoq, Greenland that shows distinct 13C-enrichment associated with this rise. We investigate the validity of this finding in face of known anomalous methane concentrations that occur at Påkitsoq. Comparison with previously published datasets to determine the robustness of our results indicates a similar trend in ice from both an Antarctic ice core and previously published Påkitsoq data measured using four different extraction and analytical techniques. The δ13CH4 trend suggests that 13C-enriched CH4 sources played an important role in the concentration increase. In a first attempt at quantifying the various contributions from our data, we apply a methane triple mass balance of stable carbon and hydrogen isotope ratios and radiocarbon. The mass balance results suggest biomass burning (42–66% of total methane flux increase) and thermokarst lakes (27–59%) as the dominant contributing sources. Given the high uncertainty and low temporal resolution of the 14CH4 dataset used in the triple mass balance, we also performed a mass balance test using just δ13C and δD. These results further support biomass burning as a dominant source, but do not allow distinguishing of thermokarst lake contributions from boreal wetlands, aerobic plant methane, or termites. Our results in both mass balance tests do not suggest as large a role for tropical wetlands or marine gas hydrates as commonly proposed.

scholarly journals Changes Of Atmospheric Methane Concentration Parallel To Climatic Changes

1990 ◽  
Vol 14 ◽  
pp. 359-359
Author(s):  
B. Stauffer ◽  
H. Oeschger ◽  
J. Schwander
Keyword(s):  
Climatic Change ◽  
Methane Concentration ◽  
Ice Core ◽  
Younger Dryas ◽  
Climatic Changes ◽  
Atmospheric Methane ◽  
Sources And Sinks ◽  
Core Samples ◽  
Climatic Optimum ◽  
Present Understanding

Measurements on ice-core samples showed that atmospheric methane concentration changed with the large climatic cycles during the last two glaciations (Stauffer and others, 1988; Raynaud and others, 1988). The methane concentration is lower in cold periods and higher in warm periods. In this paper we discuss the results of CH4 measurements of samples from periods of minor climatic change, like the climatic optimum 8000 years B.P. and the Younger Dryas period about 10 000 to 11 000 years B.P.. The data are interpreted in terms of the present understanding of methane sources and sinks.

scholarly journals Changes Of Atmospheric Methane Concentration Parallel To Climatic Changes

1990 ◽  
Vol 14 ◽  
pp. 359
Author(s):  
B. Stauffer ◽  
H. Oeschger ◽  
J. Schwander
Keyword(s):  
Climatic Change ◽  
Methane Concentration ◽  
Ice Core ◽  
Younger Dryas ◽  
Climatic Changes ◽  
Atmospheric Methane ◽  
Sources And Sinks ◽  
Core Samples ◽  
Climatic Optimum ◽  
Present Understanding

Measurements on ice-core samples showed that atmospheric methane concentration changed with the large climatic cycles during the last two glaciations (Stauffer and others, 1988; Raynaud and others, 1988). The methane concentration is lower in cold periods and higher in warm periods. In this paper we discuss the results of CH4 measurements of samples from periods of minor climatic change, like the climatic optimum 8000 years B.P. and the Younger Dryas period about 10 000 to 11 000 years B.P.. The data are interpreted in terms of the present understanding of methane sources and sinks.

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