Greenland's Jakobshavn Glacier Reacts to Changing Ocean Temperatures

This visualization shows a variety of data from the oceans and ice to help explain why the Jakobshavn glacier grew thicker and advanced between 2016 and 2017.This video is also available on our YouTube channel. This image shows the change in the elevation of the Jakobshavn glacier between 2016 and 2017. Blue colors indicate a thickening of the glacier while orange/red indicates a slight decrease in the surrounding region. Yellow indicates no change in elevation between the years. A colorbar shows the values in meters of elevation change. This image shows the change in the elevation of the Jakobshavn glacier between 2016 and 2017. Blue colors indicate a thickening of the glacier while orange/red indicate a slight decrease in the surrounding region. Yellow indicates no change between the years. No colorbar is shown on this image. The colorbar used to map the colors depicting the change in elevation of the surface between 2016 and 2017 on the radar-measured topography. This image shows the bathymetry (shape and depth) of the ocean floor around Greenland. The blue arrows show the Greenland current, which flows around the southern tip of Greenland. The currents are from the ECCO ocean circulation model. To enhance the view of the ocean currents, the bathymetry of the ocean floor has been exaggerated by a factor of 30x. This image shows the water temperature in the Disko Bay in 2017 from the surface down to a depth of about 400 meters. Red tones indicate warmer water and blue tones indicate cooler. The bathymetry of the ocean floor has been exaggerated by 40x to enhance the view of the temperature data. This image shows the water temperature in the Disko Bay in 2000 from the surface down to a depth of about 400 meters. Red tones indicate warmer water and blue tones indicate cooler. The bathymetry of the ocean floor has been exaggerated by 40x to enhance the view of the temperature data. This image shows the water temperature in the Disko Bay in 1979 from the surface down to a depth of about 400 meters. Red tones indicate warmer water and blue tones indicate cooler. The bathymetry of the ocean floor has been exaggerated by 40x to enhance the view of the temperature data. This image shows the average motion of the Greenland Ice Sheet between September 1, 2016 and June 23, 2017 as colored flow arrows, with shorter blue flow lines indicating slower movement and longer, red lines indicating faster flow. This visualization shows the Jakobshavn Glacier is blanketed by more than 40,000 radar observations. These data show the change in elevation between 2016 and 2017 as measured by an aircraft. These elevation changes are colored so that blue colors indicate an rise in the elevation and orange/red colors indicate a fall. The deepest blue color reflects the advance of the glacier from the 2016 front. Jakobshavn Glacier is Greenland's largest and fastest moving glacier. Over the last 20 years, the glacier, known in Greenlandic as Sermeq Kujalleq, has retreated, sped up and thinned. The data shown here reveal that Jakobshavn’s retreat has reversed. Between 2016 and 2018, the glacier advanced and got thicker. Scientists from NASA’s Jet Propulsion Laboratory have linked these changes to cooling of the ocean waters that reach Jakobshavn after traveling around the southern tip of Greenland and reaching into Disko Bay. (See the science paper here) The ocean cooling was likely related to the natural cycles of warming and cooling that happen in the Atlantic as part of the North Atlantic Oscillation. The strong influence of the ocean on the ice loss from Jakboshavn is somewhat surprising because the role of the ocean has been unclear since the glacier’s floating extension, called an ice tongue, disintegrated in 2003. These results mean that future projections of sea level rise will also need to account for the ocean changes in order to accurately predict how fast Greenland’s ice will melt in a warming climate. This visualization shows a variety of data from the oceans and ice to help explain why Jakobshavn glacier grew thicker and advanced between 2016 and 2017. Initially, the average flow of ice across the Greenland Ice Sheet in these years is shown as colored flow arrows, with blue shades indicating slower movement and red indicating faster. As we draw near we see a large bay named Disko Bay located just to the west of the narrow inlet, or fjord, that is home to Jakobshavn glacier. The water is cut away to reveal the historical temperature of the bay, to a depth of about 400 meters. Around Greenland, water below 150 m depth tends to be warmer than water near the surface. The change in temperature between 1952 and 2017 is shown using blue tones for colder water and red tones for warmer. The deep water warms through most of the 1990s, but cools dramatically after 2015. The ocean temperature changes are shown a second time, with a brief pause on 1979 to see the initial cooler water temperature, 2000 to view the warming and 2017 to view the current cooling trend.The visualization pulls out to show the entire Greenland Ice Sheet while ocean is drained to reveal the shape and depth of the ocean floor around the ice sheet. Data from the ECCO ocean circulation model shows ocean currents carrying water around the southern tip of Greenland and up the west coast, where it eventually enters Disko Bay and reaches Jakboshavn glacier. When we zoom in to the Jakobshavn glacier again, we see the glacier is blanketed by more than 40,000 radar observations. These data show the change in elevation between 2016 and 2017 as measured by an aircraft. These elevation changes are colored so that blue colors indicate an rise in the elevation and orange/red colors indicate a fall. The deepest blue color reflects the advance of the glacier from the 2016 front, appearing in the video as a shaded cliff, to its more advanced location in 2017. Farther downstream in the fjord the patches of blue and red show icebergs, which have detached from the front. Related pages