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   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    A once-stable glacier in Greenland is now rapidly disappearing    
    Study finds warming Atlantic waters threaten previously stable glaciers   
      
      
     Date:   
         April 19, 2023   
     Source:   
         Ohio State University   
     Summary:   
         As climate change causes ocean temperatures to rise, one of   
         Greenland's previously most stable glaciers is now retreating at   
         an unprecedented rate, according to a new study.   
      
      
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   FULL STORY   
   ==========================================================================   
   As climate change causes ocean temperatures to rise, one of Greenland's   
   previously most stable glaciers is now retreating at an unprecedented   
   rate, according to a new study.   
      
      
   ==========================================================================   
   Led by researchers at The Ohio State University, a team found that between   
   2018 and 2021, Steenstrup Glacier in Greenland has retreated about 5   
   miles, thinned about 20%, doubled in the amount of ice it discharges   
   into the ocean, and quadrupled in velocity. According to the study,   
   such a rapid change is so extraordinary among Greenland ice formations   
   that it now places Steenstrup in the top 10% of glaciers that contribute   
   to the entire region's total ice discharge.   
      
   The study was published today in Nature Communications.   
      
   The Steenstrup Glacier is part of The Greenland Ice Sheet, a body of ice   
   that covers nearly 80% of the world's largest island, which is also the   
   single largest contributor to global sea rise from the cryosphere, the   
   portion of Earth's ecosystem that includes all of its frozen water. While   
   the region plays a crucial part in balancing the global climate system,   
   the area is steadily shrinking as it sheds hundreds of billions of tons   
   of ice each year because of global warming.   
      
   Over the past few decades, much of this loss has been attributed to   
   accelerated ice discharge from tidewater glaciers, glaciers that make   
   contact with the ocean. Many glaciologists believe that this recent   
   uptick in ice discharge can be explained by the intrusion of warming   
   waters that are being swept from the Atlantic into Greenlandic fjords --   
   critical oceanic gateways that can impact the stability of local glaciers   
   and the health of polar ecosystems.   
      
   The research team aimed to test that theory by examining a glacier in the   
   southeastern region of Greenland called K.I.V Steenstrups Nordre Brae,   
   an entity more colloquially known as the Steenstrup Glacier.   
      
   "Up until 2016, there was nothing to suggest Steenstrup was in any   
   way interesting," said Thomas Chudley, lead author of the study, who   
   completed this work as a research associate at the Byrd Polar and Climate   
   Research Center.   
      
   Chudley is now a Leverhulme research fellow at Durham University in   
   the UK.   
      
   "There were plenty of other glaciers in Greenland that had retreated   
   dramatically since the 1990s and increased their contribution to sea   
   level rise, but this really wasn't one of them."  As far as scientists   
   knew, Steenstrup had not only been stable for decades but was generally   
   insensitive to the rising temperatures that had destabilized so many   
   other regional glaciers, likely because of its isolated position in   
   shallow waters.   
      
   It wasn't until Chudley and his colleagues compiled observational and   
   modeling data from previous remote sensing analyses on the glacier   
   that the team realized Steenstrup was likely experiencing melt due to   
   anomalies in deeper Atlantic water.   
      
   "Our current working hypothesis is that ocean temperatures have forced   
   this retreat," Chudley said. "The fact that the glacier's velocity has   
   quadrupled in just a few years opens up new questions about how fast   
   large ice masses can really respond to climate change."  In recent   
   years, glaciologists have been able to use satellite data to estimate   
   the potential volume of glacial ice stored at the poles and how it might   
   affect current sea levels. For instance, if the Greenland Ice Sheet were   
   to melt, Earth's sea levels could rise by nearly 25 feet. In contrast,   
   if the ice sheet in Antarctica were to fall apart, it's possible that   
   oceans would rise by nearly 200 feet, Chudley said.   
      
   While Greenland and Antarctica would take centuries to collapse   
   completely, the global cryosphere has the potential to cause sea levels   
   to rise about six feet this century if the West Antarctic Ice Sheet   
   undergoes collapse.   
      
   As around 10% of the planet's population lives in low-lying coastal zones,   
   Chudley said that any significant rise in sea level can cause increased   
   risk to low-lying islands and coastal communities from storm surges and   
   tropical cyclones.   
      
   In the United States, sea level rise poses a particular risk to coastal   
   cities in places like Florida or Louisiana, Chudley said. But that doesn't   
   necessarily mean it's too late to stop such a future from happening. If   
   climate policies evolve rapidly, humans might have a chance at halting   
   the worst of sea level rise, Chudley said.   
      
   Overall, Steenstrup's unique behavior reveals that even long-term stable   
   glaciers are susceptible to sudden and rapid retreat as warmer waters   
   begin to intrude and influence new environments.   
      
   While the research says continued scientific observation of the Steenstrup   
   Glacier should be a priority, it concludes other similar glaciers also   
   deserve attention because of their potential to retreat due to warming   
   waters.   
      
   Understanding more about these interactions could provide key insight   
   into how glaciers thrive in other locations around the world and even   
   become an indicator of how these environments might change in the future.   
      
   "What's happening in Greenland right now is kind of the canary in the   
   coal mine of what might happen in West Antarctica over the next few   
   centuries," Chudley said. "So it would be great to be able to get into   
   the fjord with real on-the- ground observations and see how and why   
   Steenstrup has changed."  This work was supported by NASA. Other Ohio   
   State co-authors were Ian M. Howat and Adelaide Negrete of the Byrd   
   Polar and Climate Research Center. Michalea D.   
      
   King of the University of Washington was also a co-author.   
      
       * RELATED_TOPICS   
             o Earth_&_Climate   
                   # Global_Warming # Climate # Ice_Ages #   
                   Snow_and_Avalanches   
             o Fossils_&_Ruins   
                   # Early_Climate # Ancient_DNA # Evolution # Origin_of_Life   
       * RELATED_TERMS   
             o Ice_sheet o Greenland_ice_sheet o Paleoclimatology   
             o Global_warming_controversy o Global_climate_model o   
             Climate_change_mitigation o Climate_engineering o Global_warming   
      
   ==========================================================================   
   Story Source: Materials provided by Ohio_State_University. Original   
   written by Tatyana Woodall. Note: Content may be edited for style   
   and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. T. R. Chudley, I. M. Howat, M. D. King, A. Negrete. Atlantic water   
         intrusion triggers rapid retreat and regime change at previously   
         stable Greenland glacier. Nature Communications, 2023; 14 (1) DOI:   
         10.1038/ s41467-023-37764-7   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/04/230419125120.htm   
      
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