Constraints on the Late Holocene Anthropogenic Contribution to the Atmospheric Methane Budget

• Main Authors: Mitchell, Logan, Brook, Edward J., Lee, James E., Buizert, Christo, Sowers, Todd
• Format: Article in Journal/Newspaper
• Language: English; unknown
• Published: American Association for the Advancement of Science
• Subjects: Antarc*; Antarctica; Greenland; ice core
• Online Access: https://ir.library.oregonstate.edu/concern/articles/h989r5001

The origin of the late pre-industrial Holocene (LPIH) increase in atmospheric methane concentrations has been much debated. Hypotheses invoking changes in solely anthropogenic sources or solely natural sources have been proposed to explain the increase in concentrations. Here two high-resolution, high-precision ice core methane concentration records from Greenland and Antarctica are presented and are used to construct a high-resolution record of the methane inter-polar difference (IPD). The IPD record constrains the latitudinal distribution of emissions and shows that LPIH emissions increased primarily in the tropics with secondary increases in the subtropical northern hemisphere. Anthropogenic and natural sources have different latitudinal characteristics, which are exploited to demonstrate that both anthropogenic and natural sources are needed to explain LPIH methane concentration changes. This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science on Volume 342 Issue 6161, November 22, 2013, DOI:10.1126/science.1238920.