Orbital and millennial-scale features of atmospheric CH4 over the past 800,000 years
By L. Loulergue, A. Schilt, R. Spahni, V. Masson‐Delmotte, T. Blunier, B. Lemieux, J. Barnola, D. Raynaud, T. Stocker, J. Chappellaz. Nature, 2008
1,007 citations recorded by the source corpus.
Atmospheric methane is an important greenhouse gas and a sensitive indicator of climate change and millennial-scale temperature variability. Its concentrations over the past 650,000 years have varied between ∼350 and ∼800 parts per 109 by volume (p.p.b.v.) during glacial and interglacial periods, respectively. In comparison, present-day methane levels of ∼1,770 p.p.b.v. have been reported. Insights into the external forcing factors and internal feedbacks controlling atmospheric methane are essential for predicting the methane budget in a warmer world. Here we present a detailed atmospheric methane record from the EPICA Dome C ice core that extends the history of this greenhouse gas to 800,000 yr before present. The average time resolution of the new data is ∼380 yr and permits the identification of orbital and millennial-scale features. Spectral analyses indicate that the long-term variability in atmospheric methane levels is dominated by ∼100,000 yr glacial–interglacial cycles up to ∼400,000 yr ago with an increasing contribution of the precessional component during the four more recent climatic cycles. We suggest that changes in the strength of tropical methane sources and sinks (wetlands, atmospheric oxidation), possibly influenced by changes in monsoon systems and the position of the intertropical convergence zone, controlled the atmospheric methane budget, with an additional source input during major terminations as the retreat of the northern ice sheet allowed higher methane emissions from extending periglacial wetlands. Millennial-scale changes in methane levels identified in our record as being associated with Antarctic isotope maxima events are indicative of ubiquitous millennial-scale temperature variability during the past eight glacial cycles.
Subfields: Atmospheric Science, Environmental Chemistry
View Paper: https://www.semanticscholar.org/paper/69d5b8a32192076da40576943fc8fe6a129332eb
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Atmospheric Science
In Environmental Chemistry
Citations in the corpus
- Deglaciation in the tropical Indian Ocean driven by interplay between the regional monsoon and global teleconnections (2013, background): “coincides with the increase in atmospheric methane as determined from ice cores (Brook et al., 1996; Loulerge et al., 2008).”
- Global vegetation patterns of the past 140,000 years (2020, methodology): “Atmospheric carbon dioxide concentration for each time slice was determined according to Vostok ice-core data (Loulergue et al., 2008; Petit et al., 1999) using the EDC3 chronology (Parrenin et al., 2007).”
- Atmospheric CH4 in the first decade of the 21st century: Inverse modeling analysis using SCIAMACHY satellite retrievals and NOAA surface measurements (2013, background): “[3] Measurements of air trapped in polar firn and ice cores show that contemporary atmospheric CH4 is 2.5 times higher than that in preindustrial times (~1750) [Etheridge et al., 1998] and unprecedented during the last 800,000 years [Loulergue et al., 2008; Spahni et al., 2005].”
- Biological and geophysical feedbacks with fire in the Earth system (2018, background): “Composite records of (a) CO2 and (b) CH4 concentration from Antarctic ice cores (Loulergue et al 2008, Lüthi et al 2008); (c) global biomass burning reconstruction (Daniau et al 2012) showing increasing fire when CO2 and CH4 increase during our present Holocene interglacial; (d) biomass burning…”
- Where to find 1.5 million yr old ice for the IPICS "Oldest-Ice" ice core (2013, background): “Over this time both climate and greenhouse gases vary mainly in parallel (Loulergue et al., 2008; Petit et al., 1999; Lüthi et al., 2008).”