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The Larsen Ice Shelf System, Antarctica (LARISSA):

                            Polar Systems Bound Together, Changing Fast






          Julia S. Wellner, University of Houston, Dept. of Earth and Atmospheric Sciences, Science & Research Building 1, 3507 Cullen Blvd.,
          Room 214, Houston, Texas 77204-5008, USA; Ted Scambos, Cooperative Institute for Research in Environmental Sciences, University
          of Colorado Boulder, Boulder, Colorado 80303, USA; Eugene W. Domack*, College of Marine Science, University of South Florida,
          140 7th Avenue South, St. Petersburg, Florida 33701-1567, USA; Maria Vernet, Scripps Institution of Oceanography, University of
          California San Diego, 8622 Kennel Way, La Jolla, California 92037, USA; Amy Leventer, Colgate University, 421 Ho Science Center,
          13 Oak Drive, Hamilton, New York 13346, USA; Greg Balco, Berkeley Geochronology Center, 2455 Ridge Road, Berkeley,
          California 94709, USA; Stefanie Brachfeld, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, USA;
          Mattias R. Cape, University of Washington, School of Oceanography, Box 357940, Seattle, Washington 98195, USA; Bruce Huber,
          Lamont-Doherty Earth Observatory, Columbia University, 61 US-9W, Palisades, New York 10964, USA; Scott Ishman, Southern
          Illinois University, 1263 Lincoln Drive, Carbondale, Illinois 62901, USA; Michael L. McCormick, Hamilton College, 198 College
          Hill Road, Clinton, New York 13323, USA; Ellen Mosley-Thompson, Dept. of Geography, Ohio State University, 1036 Derby Hall,
          154 North Oval Mall, Columbus, Ohio 43210, USA; Erin C. Pettit , University of Alaska Fairbanks, Dept. of Geosciences, 900 Yukon
                                                             #
          Drive, Fairbanks, Alaska 99775, USA; Craig R. Smith, University of Hawaii at Mānoa, 2500 Campus Road, Honolulu, Hawaii
          96822, USA; Martin Truffer, University of Alaska Fairbanks, Geophysical Institute, 2156 Koyukuk Drive, Fairbanks, Alaska 99775,
          USA; Cindy Van Dover, Nicholas School of the Environment, Duke University, Grainger Hall, 9 Circuit Drive, Box 90328, Durham,
          North Carolina 27708, USA; and Kyu-Cheul Yoo, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Korea


          ABSTRACT                           to the rest of the planet as well—and it    northerly sections of the Larsen Ice Shelf
            Climatic, cryospheric, and biologic   is generally warmer than the rest of   disintegrated. Covered with melt ponds and
          changes taking place in the northern   Antarctica. Both its Holocene and modern   riven with wide cracks, these 200-m-thick
          Antarctic Peninsula provide examples for   glaciological retreats offer a picture of how   ice shelves lost thousands of square kilo‐
          how ongoing systemic change may pro‐  larger areas of Antarctica farther south   meters of area in just days to weeks (~1500
          gress through the entire Antarctic system.    might change under future warming.  km  and 3250 km , respectively, for the
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          A large, interdisciplinary research project                           Larsen A and B ice shelves; for compari-
          focused on the Larsen Ice Shelf system,   INTRODUCTION                son, Rhode Island is ~3150 km ). The lost
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          synthesized here, has documented dramatic   Ice sheets cover most of the Antarctic   areas of ice broke into myriad small ice
          ice cover, oceanographic, and ecosystem   continent and, in some places along the   blocks that toppled over, creating a rapidly
          changes in the Antarctic Peninsula during   margin, connect to ice that has flowed from   expanding floating mass of ice rubble
          the Holocene and the present period of   the land and now floats above liquid water.   (MacAyeal et al., 2003). These breakup
          rapid regional warming. The responsive-  These areas of floating ice, called ice   events stunned glaciologists and have
          ness of the region results from its position   shelves, are dynamic in space and time and,   become iconic examples of the effects of
          in the climate and ocean system, in which a   while their loss does not directly contribute   global climate change, rapid regional
          narrow continental block extends across   to sea-level change since the ice is already   warming, and ice-shelf instability.
          zonal atmospheric and ocean flow, creating   floating, they serve as a buttressing force to   The Antarctic Peninsula has been among
          high snow accumulation, strong gradients   the glaciers behind them (Scambos et al.,   the fastest-warming areas on Earth. Data
          and gyres, dynamic oceanography, outlet   2004). Among the most sensitive ice   from weather stations and ice cores show a
          glaciers feeding into many fjords and bays   shelves are those in the northern Antarctic   2 to 3 °C increase in mean temperatures
          having steep topography, and a continental   Peninsula. The major iceberg calving event   over the past 80 years (Zagorodnov et al.,
          shelf that contains many glacially carved   on the Larsen C Ice Shelf in 2017 refocused   2012; Barrand et al., 2013). The trend is
          troughs separated by areas of glacial sedi-  attention on the ongoing ice loss from the   attributed to the combined, and probably
          ment accumulation. The microcosm of the   Larsen Ice Shelf and the rapid changes in   linked, effects of an increased northwest-
          northern Antarctic Peninsula has a ten-  climate, ice, ocean, and life in this part of   erly flow of warm, maritime air across the
          dency to change rapidly—rapid relative not   Antarctica. In January 1995 and again   Antarctic Peninsula and a reduction in sea-
          just to Antarctica’s mainland but compared   in March 2002, large areas of the more   ice extent in the northern Bellingshausen



          GSA Today, v. 29, https://doi.org/10.1130/GSATG382A.1. Copyright 2019, The Geological Society of America. CC-BY-NC.

          *Deceased
          # Now at Oregon State University, College of Earth, Ocean and Atmospheric Sciences, 104 CEOAS Admin. Building, Corvallis, Oregon 97331, USA.

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