{"600192":{"#nid":"600192","#data":{"type":"event","title":"Reconstructing Last Interglacial Sea Level on a Deforming Earth","body":[{"value":"\u003Ch4\u003EEAS Spring 2018 Seminar Series Presents: Dr. Jacky Austermann, Columbia University\u003C\/h4\u003E\r\n\r\n\u003Cp\u003ETo gain\u0026nbsp;insight into the question of ice sheet stability and sea level change in the\u0026nbsp;face of global warming, scientists have turned to studying warm periods in the\u0026nbsp;geologic past. The\u0026nbsp;Last Interglacial (LIG), ~125 ka, has been of particular\u0026nbsp;interest in this regard since atmospheric CO2\u0026nbsp;concentrations during\u0026nbsp;the LIG were comparable to pre-industrial values and\u0026nbsp;temperatures were\u0026nbsp;consistent with simulations of 1-2\u0026ordm; global warming.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EEstimating\u0026nbsp;peak global mean sea level, or equivalently minimum ice volumes, during the\u0026nbsp;Last Interglacial requires that the elevation of local sea level records be\u0026nbsp;corrected for\u0026nbsp;processes that distort local sea level relative to the global\u0026nbsp;average. One such process is glacial isostatic adjustment (GIA), which is the\u0026nbsp;change in topography that occurs due to\u0026nbsp;the loading (or unloading) of the Earth\u0026nbsp;with ice and water. Studies that have taken this process into account conclude\u0026nbsp;that LIG global mean sea level peaked 6-9m above present-levels.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EIn this\u0026nbsp;talk I will address previously unrecognized uncertainties in the GIA correction\u0026nbsp;that stem from our incomplete knowledge of the temporal evolution of ice sheets\u0026nbsp;prior to and\u0026nbsp;during the LIG. I will further talk about the role of dynamic\u0026nbsp;topography in deforming and biasing the LIG sea level record globally.\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EDynamic\u0026nbsp;topography is the topography that is\u0026nbsp;supported by viscous flow and buoyancy\u0026nbsp;variations in the Earth\u0026rsquo;s mantle. To date, this global scale process has been\u0026nbsp;ignored in sea level studies of Pleistocene interglacials,\u0026nbsp;including the LIG,\u0026nbsp;under the assumption that the signal would be negligible. I will show that modeled\u0026nbsp;deflections span several meters, that they are significantly correlated with\u0026nbsp;observed\u0026nbsp;sea level highstands and that they are consistent with construction and\u0026nbsp;preservation attributes across different sea level indicator types.\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"A seminar by Dr. Jacky Austermann, School of Earth and Atmospheric Sciences Spring 2018 Seminar Speaker Series"}],"uid":"34458","created_gmt":"2017-12-21 15:15:39","changed_gmt":"2018-03-15 16:26:48","author":"nlawson3","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2018-04-19T12:00:00-04:00","event_time_end":"2018-04-19T12:50:00-04:00","event_time_end_last":"2018-04-19T12:50:00-04:00","gmt_time_start":"2018-04-19 16:00:00","gmt_time_end":"2018-04-19 16:50:00","gmt_time_end_last":"2018-04-19 16:50:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"hg_media":{"600167":{"id":"600167","type":"image","title":"Jacky Austermann","body":null,"created":"1513863424","gmt_created":"2017-12-21 13:37:04","changed":"1513863424","gmt_changed":"2017-12-21 13:37:04","alt":"","file":{"fid":"228800","name":"Jacky Austermann.JPG","image_path":"\/sites\/default\/files\/images\/Jacky%20Austermann.JPG","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/Jacky%20Austermann.JPG","mime":"image\/jpeg","size":173987,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/Jacky%20Austermann.JPG?itok=BCgKKP-b"}}},"media_ids":["600167"],"groups":[{"id":"364801","name":"School of Earth and Atmospheric Sciences (EAS)"}],"categories":[],"keywords":[{"id":"175623","name":"EAS Seminar"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[{"id":"78761","name":"Faculty\/Staff"},{"id":"174045","name":"Graduate students"},{"id":"78751","name":"Undergraduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EHost: Ken Ferrier\u003C\/p\u003E\r\n\r\n\u003Cp\u003ELogistics: Natasha Lawson\u003C\/p\u003E\r\n","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}