MAMMOTH BURPS: DID HUMAN IMPACTS ON THE ENVIRONMENT PREDATE THE HOLOCENE?

2009 Portland GSA Annual Meeting (18-21 October 2009)
Paper No. 50-15

Presentation Time: 5:15 PM-5:30 PM

MAMMOTH BURPS: DID HUMAN IMPACTS ON THE ENVIRONMENT PREDATE THE HOLOCENE?
SMITH, Felisa, Biology, University of New Mexico, MSC 03-2020, 1 University of New Mexico, Albuquerque, NM 87131, fasmith@unm.edu, ELLIOTT, Scott M., Climate, Ocean, Sea Ice Modeling Team, Los Alamos National Laboratory, Los Alamos, NM 87545, and LYONS, S. Kathleen, Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, Washington, DC 20013 The human-mediated extinction of large herbivorous megafauna in the late Pleistocene had profound effects on terrestrial community structure and function, but may also have influenced atmospheric gas exchange. Herbivorous mammals are major producers of methane, a potent greenhouse gas with a high global warming potential; domestic livestock currently contribute ~20% of the annual input. Here, using allometric relationships between body mass and density, methane production and estimates of geographic range, we calculate the annual decrease in methane production resulting from the extinction of 114 species of large-bodied herbivore from the Americas ~13,400-11,500 ybp. Our results suggest a loss of at least ~9.6 Tg (upper limit, 25.5 Tg) CH4 annually, sufficient to explain a significant portion (12.5-100%) of the ~200 ppbv drop detected in isotopic analyses of ice-core records. We suggest humans measurably influenced global biogeochemical processes long before the development of agriculture, complex civilizations and the obvious impacts of the industrial age.
2009 Portland GSA Annual Meeting (18-21 October 2009) General Information for this Meeting

Session No. 50 Paleontology: Extinction & Turnover Oregon Convention Center: Portland Ballroom 256 1:30 PM-5:30 PM, Sunday, 18 October 2009 Geological Society of America Abstracts with Programs, Vol. 41, No. 7, p. 161
© Copyright 2009 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.