King George Island glacier retreat – From a Glaciers Perspective

King George Bay Glacier retreat releases a new island (Point B) and expanded ice free oases in 1989 and 2022 Landat Images. Point A marks an area where the glacier had reached the coast until after 2005. Point B is the new island, Point C= new oasis, PI=Penguin Island, TP=Turret Point Oasis

King George Bay is on the southeast coast of King George Island. This coastline is comprised mainly of glacier margins ending in th sea, with limited ice free areas. The east end of the bay features the Turret Point Oasis, with Penguin Island just offshore. This oasis is a location used for breeding by Chinstrap and Adelie Penguins, and is a significant breeding area is for southern giant petrels, and Antarctic ‘blue-eyed’ shags. Elephant seals and fur seals are numerous in the latter part of the season (Korczak-Abshire,et al 2018). Here we examine Landsat images from 1989-2022 to identify changes in the glacier margin and the impact on this oasis and generation of a new island.

King George Bay Glacier retreat releases new island in Sentinel images from 2018 and 2022. Point A marks an area where the glacier had reached the coast until after 2005. Point B is the new island, Penguin Island=PI, TP=Turret Point, Point C is the new oasis.

In 1989 the Turret Point Oasis had an area of ~1 km². The King George Bay Glacier terminated on a bedrock rise at Point B. The glacier reached the coast between Turret Point and Point A. To the west there is no other ice free coastline, Point C. In 2005 the glacier was still terminating on the bedrock rise at Point B. The glacier is still reaching the coast between Point A and Turret Point and there is no ice free area near Point C. By 2018 there is a narrow finger of ice connecting to the Point B Bedrock rise and the shoreline between Turret Point and Point A is now free of glacier. there is a small strip of ice free coast near Point C. In 2022 the glacier has receded from the new island at Point B. The retreat at Point B is 950-1000 m since 1989, with a similar retreat across the broad front of the King George Bay Glacier to Point C. Glacier retreat from the shoreline near Point A has been 400 m. The Turret Point Oasis has expanded to 2 km², a doubling in size that expands oppportunity for greater diversity of flora and fauna. There is a new ~0.6 km² oasis that has formed at Point C. This is a narrow 200-400 m wide strip that is 1.7 km long. In the false color Sentinel images red indicates plant life for 12-24-2022 the Point C oasis does not have enough flora to be visible. This is in contrast to Turret Point and Penguin Island. The retreat here fits the pattern seen further west on King George Island on the Warsaw Ice Cap.

In 2016 the Arctwoski Station research survey found ~150 pairs of breeding Adlelie Penguins and 220 breeding pairs of southern giant petrels (Korczak-Abshire,et al 2018). In the Antarctic Treaty Turret Point oasis has specific visitor guidelines. The confluence of threats from climate change and human activity (Lee et al, 2022) makes Turret Point an important location to monitor. The retreat of glaciers opening up new potential breeding and feeding areas has been observed at Stephenson Lagoon on Heard Island and at Hindle Glacier on South Georgia.

Map illustrating locations bird and penguin species onTurret Point and Penguin Island from a UAV flight in 2016 from Korczak-Abshire,et al (2018)

King George Bay Glacier false color Sentinel image. Vegetation is evident on Turret Point=TP and Penguin Island=PI, but not at Poiunt C oasis.

Warsaw Icefield, King George Island, Antarctica glacier retreat and nunatak expansion in 1989, 2001 and 2018 Landsat images. E=Ecology Glacier, B=Baranowski Glacier, W=Windy Glacier, 1989 terminus locations indicated by red arrows. Point A & B are nunataks.

The Arctowski Polish Research Station is located on a relatively large ice-free oasis northeast of the Warsaw Icefield on King George Island, Antarctica. The station is on Admiralty Bay where Ecological monitoring has been conducted since the late 1970’s in order to determine the size and condition of populations of seabirds and pinnipeds. The ocean bottom has had over 800 distinct benthic species identified. A long term study of a chinstrap penguin colony on King George Islands during the last 30 years indicates the size of the breeding populations has decreased by 84% probably due to limitations of the marine food web (Korczak-Abshire et al 2012). The outlet glaciers of Warsaw Icefield experienced significant retreat and mass loss (Petlicki et al, 2017). Here we examine Landsat images from 1989 to 2017 to illustrate the changes. The Warsaw Icefield extends from 400 m to sea level.

In 1989 Baranowski and Windy Glacier terminate on the coastline lacking any significant embayment. Ecology Glacier has a wide front in a shallow embayment. Nunataks A and B are amidst the icefield. In 1990 the snowline is at 200 m with nunatak A and B in the ablation zone. In 2001 nunatak A and B are still surrounded by ice. Windy Glacier and Baranowski Glacier have retreated with embayments forming. The embayments are separated from ocean by a coastal strip of land. An embayment has also opened to the west of Windy Glacier and Point C due to glacier retreat. In 2005 the snowline is at 250 m. Baranowski glacier retreat has led to Nunatak B reaching the margin of the glacier, the embayment expanding on the north side of the margin. In 2014 Ecology Glacier has retreated opening the embayment. In 2018 Ecology Glacier has retreated 600 m since 1989 exposing several small new islands in this protected embayment. the Tidewater front is quite limited in 2018. Nunatak A is within 400 m of the edge of the icefield, whereas in 1989 the nunatak was 1.2 km from the margin. The 1989-2018 500 m retreat of Baranowski Glacier has led to the development of a dominantly land based terminus. Windy Glacier has retreated 400 m since 1989 and is now land terminating. The glacier to the west of Windy Glacier and Point C has opened a 0.5 square kilometers embayment. The retreat of Warsaw Icefield is similar to that of Endurance Glacier, Elephant Island. Petlicki et al,( 2017) indicate mass balance has not been as negative from 2012-2016 which should slow retreat. The new embayments offer potential new locations for penguins that Arctowski scientists will monitor.

Warsaw Icefield, King George Island, Antarctica glacier retreat and nunatak expansion in 1990, 2005 and 2014 Landsat images. E=Ecology Glacier, B=Baranowski Glacier, W=Windy Glacier. Point A & B are nunataks in 1989.

Map from the Arctowski Research Station in 2007 indicating glacier changes from 1978 mapped margins to 2007 dark line margin. This dark line has been annotated to be visible for this post.