17th century documents & 1970s ice maps show sea ice habitat in Svalbard has always varied greatly

Historical records show that sea ice extent along the west coast of Svalbard, Norway varied greatly in the 1600s and that there is currently more ice than was usually present at this time of year in the 17th century.

April through early June is when polar bears need sea ice the most–for feeding on newborn seals and for finding mates–and so far this spring, bears in the Western European Arctic around Svalbard, Norway have had an abundance of ice. In fact, there is only a little less ice than was normal for the late 1970s and apparently, quite a bit more than was often present in the 1600s.

Western European Arctic 1975-1979

The Western European Arctic is centered on Svalbard in the Barents Sea but includes the Denmark Strait off East Greenland and western Kara Sea off Novaya Zemlya. The map below shows average ice extent for April in the late 1970s (Degroot 2022: his figure 1). Note how much of Svalbard and Novaya Zemlya are covered in glaciers and how little ice there was around the extreme tip of southeast Greenland (Laidre et al. 2012, 2022).

Barents Sea Arctic ice extent 2023

Note the amount of pack ice butting up against the entire north shore of Svalbard, which wasn’t happening even in the late 1970s. There was more ice along the west shores of Spitsbergen (largest Svalbard island) and Novaya Zemlya, and along the north shore of Russia in the Barents Sea (west of Novaya Zemlya) but otherwise there isn’t a huge amount of difference. There is an abundance of sea ice now as there was then in the spring, when polar bears need it the most.

Here’s how current ice extent looks according to the numbers just for the Svalbard area, against an average of 1991-2020. Note that only one standard deviation is presented (two is standard).

Compare above to previous years, charts saved from the NIS archive for early May in 2009, 2012, and 2016.

Degroot’s research on whaling activities during the 17th century indicates that the west coast of Spitsbergen being largely free of sea ice by early April was the norm even during the Little Ice Age (LIA). As he puts it, on pg. 70 (my bold):

During the first decades of the seventeenth century, up to one hundred thousand bowhead whales calved and mated near Jan Mayen early each year. In the spring, the whales migrated northeast along the retreating edge of the vast expanse of congregated sea ice—ice formed by frozen salt water—that constitutes the Arctic ice pack (fig. 1). By early April, they entered feeding grounds in bays along Svalbard’s largest islands, Spitsbergen and Edgeøya, that were now largely clear of sea ice (fig. 2).

Figure 2 from his paper (below) shows that one of the primary “bays” used by bowhead whales included a huge fjord on the northwest coast of Spitsbergen with several entrances that was favoured by whalers, called Smeerenburgfjorden. “Hollander’s Bay” marks an important onshore whale processing camp established in the 1600s.

Smeerenburgfjorden is today (3 May 2023) inaccessible due to fast and pack ice (closeup of NIS chart below, see extreme upper left corner):

The large island of Edgeøya in the southeastern portion of the archipelago, mentioned by DeGroot as also being used by whales in the 1600s in early April, is also inaccessible today (3 May 2023), as the closeup ice chart below shows:

Bottom line: Sea ice extent off the west coast of Svalbard in the Western European Arctic has been highly variable in spring and summer for centuries: some decades had much less ice, some decades had much more. Currently, there is more ice than was present in early May in many years of the 1600s. Amazing how useful a bit of historical perspective can be in cooling down the hot air.

References

Degroot, D. 2022. Blood and bone, tears and oil: Climate change, whaling, and conflict in the seventeenth-century Arctic. The American Historical Review 127(1):62–99. Open access. https://doi.org/10.1093/ahr/rhac009

Laidre, K.L., Born, E.W., Gurarie, E., Wiig, O., Dietz, R. and Stern, H. 2012. Females roam while males patrol: divergence in breeding season movements of pack ice polar bears (Ursus maritimus). Proceedings of the Royal Society B 280: 1-10. DOI: 10.1098/rspb.2012.2371 Open access http://rspb.royalsocietypublishing.org/content/280/1752/20122371

Laidre, K.L., Supple, M.A., Born, E.W., et al. 2022. Glacial ice supports a distinct and undocumented polar bear subpopulation persisting in late 21st century sea-ice conditions. Science 376(6599):1333-1338.