Greenlands contribution to sea level rise
The Greenland Ice Sheet is melting! Summers last longer and new temperature records trigger enhanced surface melt: huge pools filled with meltwater and raging rivers stand out on the white ice sheet. In addition, more and more ice masses are draining - faster and faster - via the outlet glaciers at the edge of the ice sheet. This means that larger amounts of freshwater from the Greenland Ice Sheet get into the ocean - which makes a decisive contribution to sea level rise.
Ice sheet - glacier - ocean
There are over 200 glaciers around the coast of Greenland, each providing a direct connection between the ice sheet and the ocean. The ice flows in huge ice streams from the interior and drains via the numerous glaciers - thereby carrying loads of freshwater into the ocean. Conversely, changes in the ocean also have an impact on the Greenland Ice Sheet: Increased water temperatures lead to increased melting at numerous glaciers, which calving fronts extend hundreds of meters into the water. Therefore, the ocean contributes significantly to the rapid retreat of the glaciers - and thus to an increased drainage of the ice from the interior into the ocean.
Northeast Greenland glaciers
In northeastern Greenland there is a huge ice flow that transports ice far from inside the ice sheet to the coast. Over 10% of the entire mainland ice of Greenland drains here mainly via two large glaciers: Zachariæ Isstrøm and Nioghalvfjerdsbræ. The latter is also known as the 79° N Glacier and protrudes far out over the ocean: its floating glacier tongue is 80 km long and the ocean water circulates under it. The Zachariæ Isstrøm glacier tongue, on the other hand, has fallen victim to climate change in recent years - it is retreating strongly and huge icebergs break off on its calving front.
The 79°N Glacier
The (currently) longest glacier tongue in Greenland extends over a length of about 80 km long and 20-30 km width. It covers an entire long-stretched fjord with 100 to 600 m thick glacial ice. Underneath there is a cave up to 900 m deep into which warm ocean water flows continuously. The 1°C-warm water drives melting at the bottom of the glacier tongue. The meltwater in turn mixes with the surrounding water and flows out of the cavity. How will this interaction change in the future under rising air and ocean temperatures?