{"659476":{"#nid":"659476","#data":{"type":"news","title":"Coastal Glacier Retreat Linked to Climate Change","body":[{"value":"\u003Cp\u003EMore of the world\u0026rsquo;s coastal glaciers are melting faster than ever, but exactly what\u0026rsquo;s triggering the large-scale retreat has been difficult to discern because of natural fluctuations in the glaciers\u0026rsquo; surroundings.\u003C\/p\u003E\r\n\r\n\u003Cp\u003ENow, researchers at the University of Texas Institute for Geophysics (UTIG) and the Georgia Institute for Technology have developed a methodology to determine why coastal glaciers are retreating, and in turn, how much can be attributed to human-caused climate change. Attributing the human role for coastal glaciers \u0026ndash; which melt directly into the sea \u0026ndash; could pave the way to better predictions about sea level rise.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Ca href=\u0022https:\/\/doi.org\/10.5194\/tc-16-2725-2022\u0022\u003EPublished July 13\u003C\/a\u003E in the journal \u003Cem\u003EThe Cryosphere\u003C\/em\u003E, the methodology is unique because it treats rapid glacier retreat as an individual probabilistic event, like a wildfire or tropical storm. For a large retreat to happen, the glacier must retreat past its \u0026ldquo;stability threshold,\u0026rdquo; which is usually a steep rise in the underlying bedrock that helps slow its flow. The probability of that happening varies depending on local climate and ocean conditions that change with natural fluctuations and human-caused warming. Even small variations can cause large changes in a glacier\u0026rsquo;s behavior, making them hard to predict and leading to cases where glaciers were found retreating right next to ones that weren\u0026rsquo;t.\u003C\/p\u003E\r\n\r\n\u003Cp\u003ESo far, scientists have tested the approach only in computer models using simplified glaciers. They found that even modest global warming caused most glaciers to melt, or retreat.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe next step, the researchers said, is for scientists to simulate the coastal glaciers of a real ice sheet, like Greenland\u0026rsquo;s, which holds enough ice to raise sea level by about 22 feet (7 meters). That will reveal whether they are retreating due to climate change and help predict when major ice loss might next occur.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;The methodology we\u0026rsquo;re proposing is a road map towards making confident statements about what the human role is [in glacial retreats],\u0026rdquo; said glaciologist John Christian, who is a postdoctoral researcher at both The University of Texas at Austin and Georgia Tech. \u0026ldquo;Those statements can then be communicated to the public and policymakers and help in their decision making.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EOvercoming Uncertainty \u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003ECo-author and UTIG glaciologist Ginny Catania points out that the last Intergovernmental Panel on Climate Change report found there was still too much uncertainty about coastal glaciers to say whether their retreat is due to human-caused climate change or natural climate fluctuations.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe new study shows how to overcome the uncertainty by providing a methodology that accounts for differences between glaciers and natural climate fluctuations, while testing the effect of background trends such as global warming. According to Catania, the study means they can now attribute mass coastal glacier retreat to climate change and not just natural variability.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;And that\u0026rsquo;s the first time anyone\u0026rsquo;s done that,\u0026rdquo; she said.\u003C\/p\u003E\r\n\r\n\u003Cp\u003ETo test the methodology, the team ran thousands of simulations of the past 150 years with and without global warming. The simulations showed that even modest warming dramatically increased the probability of ice sheet-wide glacier retreat.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EWhen the scientists ran models without human-caused climate change, they found it virtually impossible for more than a few of the glaciers to begin retreating within years of each other.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EBy contrast, since 2000, nearly all (200) of Greenland\u0026rsquo;s 225 coastal glaciers have been in varying states of retreat.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;This study gives us a toolbox to determine the role of humans in the loss of ice from Greenland and Antarctica, to say with confidence that it\u0026rsquo;s not just coincidence,\u0026rdquo; said Georgia Tech College of Sciences glaciologist and co-author Alex Robel.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe research on coastal glaciers builds on previous work to understand the human role on the retreat of mountain glaciers \u0026mdash; which is now well-established. The latest study was funded by UTIG and the National Science Foundation. UTIG is a research arm of UT Austin\u0026rsquo;s Jackson School of Geosciences.\u003C\/p\u003E\r\n\r\n\u003Cp\u003ECitation: John Erich Christian, Alexander A. Robel, Ginny Catania.\u0026nbsp;A probabilistic framework for quantifying the role of anthropogenic climate change in marine-terminating glacier retreats.\u0026nbsp;\u003Cem\u003EThe Cryosphere\u003C\/em\u003E, 2022; 16 (7): 2725 DOI:\u0026nbsp;\u003Ca href=\u0022http:\/\/dx.doi.org\/10.5194\/tc-16-2725-2022\u0022 target=\u0022_blank\u0022\u003E10.5194\/tc-16-2725-2022\u003C\/a\u003E\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EResearchers have developed a methodology to determine why coastal glaciers are retreating, and in turn, how much can be attributed to human-caused climate change.\u003C\/p\u003E\r\n","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have developed a methodology to determine why coastal glaciers are retreating, and in turn, how much can be attributed to human-caused climate change. "}],"uid":"34602","created_gmt":"2022-07-19 16:19:10","changed_gmt":"2022-07-19 17:16:23","author":"Georgia Parmelee","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2022-07-19T00:00:00-04:00","iso_date":"2022-07-19T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"659470":{"id":"659470","type":"image","title":"Glacier 1","body":null,"created":"1658242659","gmt_created":"2022-07-19 14:57:39","changed":"1658242659","gmt_changed":"2022-07-19 14:57:39","alt":" a glacier","file":{"fid":"249960","name":"cover[54].jpeg","image_path":"\/sites\/default\/files\/images\/cover%5B54%5D.jpeg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/cover%5B54%5D.jpeg","mime":"image\/jpeg","size":692393,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/cover%5B54%5D.jpeg?itok=qbRORDlj"}},"659471":{"id":"659471","type":"image","title":"Glacier Simulation","body":null,"created":"1658242704","gmt_created":"2022-07-19 14:58:24","changed":"1658242704","gmt_changed":"2022-07-19 14:58:24","alt":"graphic of glacier simulation","file":{"fid":"249961","name":"glacieranimation-cropped[82].jpg","image_path":"\/sites\/default\/files\/images\/glacieranimation-cropped%5B82%5D.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/glacieranimation-cropped%5B82%5D.jpg","mime":"image\/jpeg","size":46577,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/glacieranimation-cropped%5B82%5D.jpg?itok=_FR1jEED"}}},"media_ids":["659470","659471"],"groups":[{"id":"1278","name":"College of Sciences"},{"id":"1188","name":"Research Horizons"},{"id":"364801","name":"EAS"},{"id":"565971","name":"Ocean Science and Engineering (OSE)"}],"categories":[],"keywords":[{"id":"187915","name":"go-researchnews"},{"id":"166926","name":"School of Earth and Atmospheric Sciences"}],"core_research_areas":[],"news_room_topics":[{"id":"71911","name":"Earth and Environment"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EGeorgia Parmelee\u003C\/p\u003E\r\n","format":"limited_html"}],"email":["georgia.parmelee@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}