new islands glacier retreat – From a Glaciers Perspective

The northern coast of the Devon Ice Cap with Lady Ann Strait at the top in a 2000 and 2017 Landsat image indicating the development of islands at Cape Caledon, at yellow arrows. See map below.

The Devon Ice Cap on Devon Island in the Canadian Arctic ice cap’s area has an area of 15,000 km², with a volume of 3980 km³. The ice cap has been the focus of an ongoing research program led by the University of Alberta Arctic and Alpine Research Group. The mass balance from 1960-2009 was cumulatively -5.6 m, with nine of the eleven most negative years occurring since 1998. Noel et al (2018) update this observation noting that Canadian Arctic ice caps have been losing mass for decades and that mass loss accelerated in 1996. This followed a significant warming (+1.1∘C), which increased the production of meltwater. This has led to widespread area losses. White and Copland (2018) quantify the change in the areal extent of 1773 glaciers on Northern Ellesmere Island from 1999 to 2015. They found regional glacier area decreased by ∼6%, with not a single glacier increasing in areal extent.

East of Belcher Glacier, a large retreating tidewater outlet of the Devon Ice Cap, maps indicate a glacier terminating at Cape Caledon, a series of rocky Points on the southern side of the Lady Ann Strait. Today the Cape Caledon Glacier no longer reaches these rocky Points that have now become islands. Here we examine Landsat images from 2000 to 2018 to illustrate the changes.

In 2000 the Cape Caledon Glacier terminates along its north side on three rocky points, yellow arrows, while the eastern margin is pinned on the northeastern most of the Points and extends nearly due south to another rocky Point, yellow arrow. In 2002 little has changed on the northern or eastern margin. By 2017 the glacier has separated from the three rocky Points on the northern margin, each is now a new island. The mid-August 2017 image indicates that the snowline is particularly high, with none of the Cape Caledon Glacier in the accumulation zone. This supports what has been observed in terms of significant changes in the nature of the firn due to increased meltwater infiltration in the region (Gascoin et al 2013). The eastern margin has retreated along most of its length, but remains attached to the rocky Point on the southern margin. In 2018 the islands remain separated from the glacier, but have some sea ice still around them. The eastern margin that had terminated at the northeast most rocky Point has retreated from 500-700 m along nearly the entire front, except for the very southern margin. The generation of new islands is a process occurring across the Arctic as glaciers recede (Ziaja and Ostafin, 2018).

The northern coast of the Devon Ice Cap with Lady Ann Strait at the top in a 2002 and 2018 Landsat image indicating the development of islands at Cape Caledon, at yellow arrows.

Map of Cape Caledon on the north coast of the Devon Ice Cap

The northern coast of the Devon Ice Cap with Lady Ann Strait at the top in a 2017 Landsat image indicating the development of islands at Cape Caledon, at yellow arrows, surrounded by some sea ice.

Rink Gletscher is just east of Docker Smith Glacier in Melville Bay Northwest Greenland. It should not be confused with the large and more famous Rinks Isbrae 5 degrees latitude south. This is a minor outlet glacier with a 4 km wide calving front.
GEUS Map
McFadden et al (2011) noted that several larger neighboring glaciers in Northwest Greenland Sverdrups, Steenstrup, Upernavik, and Umiamako underwent signficant retreat, acceleration and thinning between 2002 and 2007. Steenstrup was the focus of a recent post where retreat of up to 5 kilometers since 1999 had led to new island formation. Howat and Eddy (2011) observed that 98% of glaciers in northwest Greenland retreated from 2000-2010 with a mean rate of 127 m per year. Van As (2011) has noted that net annual ablation after 2000 has been consistently higher in the region. Enderlin and Howat (2013) note that basal melting is 0.3-0.5 m day in this region, much higher than surface ablation. Here we again utilize the exceptional Landsat record of the changing earth surface with imagery from 1999, 2001. 2012 and 2013. In 1999 the glacier extends to the orange arrow on the west margin and a small peninsula, yellow arrow, on the east margin. A nunatak is located 3.5 to 4 km behind the calving front, pink arrow. By 2001 retreat of the western margin is evident, but only minor retreat in the east. By 2012 the glacier has retreated back to the nunatak with the greatest retreat in the center of the glacier and less at both margins. By 2013 it is evident that the island by the yellow arrow, has been freed from the ice sheet. The center of the glacier has retreated 3.5 to 4 km to the nunatak, pink arrow. Retreat is 3 km along the eastern margin and approximately 1.8 km on the western margin. A series of red arrows indicates a point where the surface slope of the glacier increases, resulting in greater crevassing. This reflects a bedrock step in elevation as well. The recent retreat has largely been via calving. This retreat can rapidly continue back to the red arrows, at that point water depths will be greatly reduced as will calving. The retreat here is coincident with the pattern of retreat and new island generation seen at Kong Oscar Glacier, Alison Glacier and Upernavik Glacier.

1999 Landsat Image