AffiliationUniv Arizona, Dept Geosci
millennial-scale climate variability
MetadataShow full item record
PublisherAMER GEOPHYSICAL UNION
CitationThirumalai, K., Clemens, S. C., & Partin, J. W. (2020). Methane, Monsoons, and Modulation of Millennial‐Scale Climate. Geophysical Research Letters, 47(9), e2020GL087613.
JournalGEOPHYSICAL RESEARCH LETTERS
Rights© 2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License.
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AbstractEarth's orbital geometry exerts a profound influence on climate by regulating changes in incoming solar radiation. Superimposed on orbitally paced climate change, Pleistocene records reveal substantial millennial-scale variability characterized by abrupt changes and rapid swings. However, the extent to which orbital forcing modulates the amplitude and timing of these millennial variations is unclear. Here we isolate the magnitude of millennial-scale variability (MMV) in two well-dated records, both linked to precession cycles (19,000- and 23,000-year periodicity): composite Chinese speleothem delta O-18, commonly interpreted as a proxy for Asian monsoon intensity, and atmospheric methane. At the millennial timescale (1,000-10,000 years), we find a fundamental decoupling wherein precession directly modulates the MMV of methane but not that of speleothem delta O-18, which is shown to be strikingly similar to the MMV of Antarctic ice core delta H-2. One explanation is that the MMV of methane responds to changes in midlatitude to high-latitude insolation, whereas speleothem delta O-18 is modulated by internal climate feedbacks.
NoteOpen access article
VersionFinal published version
SponsorsNational Science Foundation
Except where otherwise noted, this item's license is described as © 2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License.