MitchellLoganCEOASConstraintsLateHoloceneSupplementaryMaterials.pdf

• Main Authors: Mitchell, Logan, Brook, Edward J., Lee, James E., Buizert, Christo, Sowers, Todd
• Language: unknown
• Subjects: Greenland; Antarc*; Antarctica; ice core
• Online Access: https://ir.library.oregonstate.edu/concern/articles/qj72p934z

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.