Glacier Retreat Brings New Islands

In some parts of the world, new islands are forming due to glacier retreat. Glaciers, dynamically responding to the change in temperature and precipitation, reveal the big picture of climate variability and change. During the Little Ice Age (LIA) with cooler temperatures, glaciers around the world grew substantially, from approximately 1350 to 1850. It was then followed by glacier retreat until 1940 as the globe warmed up. Since 1980, glacier recession has become unprecedentedly rapid, in line with significant global warming. “Glaciers are like a visual checking account of the status of the cold part of the ecosystem”, said Dan Fagre, a U.S. Geological Survey research ecologist.

Sea ice in the Weddell Sea. Source: Hamilton College.

The substantial melting, particularly in Greenland and Antarctica where vast glacial ice concentrates, contributes to major sea level rise globally. While small island countries are worried about being submerged by the overwhelming sea level rise, new islands have emerged near Antarctic Peninsula and Greenland. Mauri Pelto, glaciologist and professor of environmental science at Nichols College, discussed the island formation processes in his blog posts on American Geophysical Union Blogosphere.

One of the island formations occurred in Leroux Bay on the west coast of the Antarctic Peninsula in Graham Land. From 1950 to 2000, the air temperature in the northern Antarctic Peninsula rose by 2.5ºC. As a result, 87% glaciers and ice shelves on the Peninsula were lost in the last two decades. The widespread loss of mass from ice shelves in Antarctica is mainly via basal melting. The spectacular collapse of ice-sheets and glaciers has enabled scientists to examine sediments that had accumulated beneath the floating ice shelves. Retreat from 1990 to 2015 averages 2.1 kilometers. By 2001, the glacier front had already retreated significantly and the new island had detached from the mainland, shown by the yellow arrow on the Google Earth image.

Google Earth image indicating glacier flow directions with blue arrows, island the yellow arrow and glacier terminus the red arrow. Source: AGU
Google Earth image indicates glacier flow directions with blue arrows, island the yellow arrow and glacier terminus the red arrow. Source: AGU

Steenstrup Glacier is located in Northwest Greenland. It has retreated 10km over the past 60 years. Kjer Glacier is immediately to the south of Steenstrup. The area between Steenstrup Glacier and Kjer Glacier is Red Head. Steenstrup Glacier’s northern boundary is near Cape Seddon. Steenstrup Glacier experienced rapid thinning of up to nearly 100m per year since 2000, with a 20% acceleration rate. The glacier could still reach Red Head in 1999, though the connection was less than 2km wide. By 2013, the connection to Red Head had been completely lost, making it an independent island.

The map of Steenstrup Glacier. Source: AGU
The map of Steenstrup Glacier. Source: AGU

The 2012 Google Earth image indicates the narrow connection between the glacier and Cape Sneddon at that time and the unique pattern of deep fractures in the glacier. It is clear that the end of Cape Sneddon will very likely to be part of an island in future summers. The connection to the island at the south end of Kjer Glacier has become much narrower since 1999 and will probably follow the route of Red Head and Cape Sneddon.

Google Earth 2012 image of Cape Sneddon. Source: AGU

Professor Mauri Pelto examined in his posts new island generation from the retreat of Leroux Bay Glacier and Steenstrup Glacier in great detail. The climate change induced glacier melting is creating the seesaw of potentially losing and gaining new islands at the same time.

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