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

From Polar Bear Science

Susan Crockford

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.


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.

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Rud Istvan
May 6, 2023 2:04 pm

I was able to document this same truth for the entire Canadian Arctic from about 1900 to 2014 in essay Northwest Passage in ebook Blowing Smoke.

Reply to  Rud Istvan
May 7, 2023 2:24 pm

Ichthyosaur fossil from Svalbard shows they night have evolved before and survived the end Permian “Great Dying”, largest mass extinction of the Phanerozoic Eon, ie the last 541 million years.


Reply to  Rud Istvan
May 7, 2023 2:51 pm

Bowhead whale skull shows limited extent of early Holocene Arctic sea ice:


May 6, 2023 3:12 pm

Late 21st century? It’s still early in the century.

Does “late” in the cited article title mean after the March ice peak?

John Hultquist
Reply to  Milo
May 6, 2023 5:07 pm

No. It means they are looking to the future in case CAGW creates a different situation.
 “These bears occupy sea-ice conditions resembling those projected for the High Arctic in the late 21st century, with an annual ice-free period that is >100 days longer than the estimated fasting threshold for the species. ” 

I suspect RCP8.5 is hidden in there some how.

Reply to  John Hultquist
May 6, 2023 6:28 pm

I see.

In that case, how did polar bears survive the Holocene Climatic Optimum, so much warmer than now in the Arctic, let alone the Eemian Interglacial? Polies had evovled less then, but there were already seal-eating specialized brown bears.

John Hultquist
Reply to  Milo
May 6, 2023 7:32 pm

You might find this interesting.
 date was 1817

John Daly home page http://www.john-daly.com/

“It will without doubt have come to your Lordship’s knowledge that a considerable change of climate, inexplicable at present to us, must have taken place in the Circumpolar Regions, by which the severity of the cold that has for centuries past enclosed the seas in the high northern latitudes in an impenetrable barrier of ice has been during the last two years, greatly abated.

(This) affords ample proof that new sources of warmth have been opened and give us leave to hope that the Arctic Seas may at this time be more accessible than they have been for centuries past, and that discoveries may now be made in them not only interesting to the advancement of science but also to the future intercourse of mankind and the commerce of distant nations.”
President of the Royal Society, London, to the Admiralty, 20th November, 1817

Reply to  John Hultquist
May 6, 2023 7:46 pm


And for the clarification on “late 21st century”. Clearly, I didn’t read the relevant portion of Dr. Susan’s post.

Arctic ice waxes and wanes on a quasi-regular cycle. The Carbonari conspirators in the ’80s knew that it would repeat its 1930s disappearing act in coming decades, falling from its 1970s heights.

Martin Brumby
Reply to  John Hultquist
May 6, 2023 8:59 pm

Climate actually changes?

Who knew?

I thought we were those nasty folk that “Deny Climate!”

Reply to  Martin Brumby
May 6, 2023 9:07 pm

Without any human affects, Earth’s climate has changed from an atmosphere of gaseous rock to an icy surface to the nearly ideal conditions of the Age of Dinosaurs, with four or five times present CO2, to today’s frigid, close to plant starvation CO2 concentrations. Thank humans for keeping the plants alive by adding vital CO2 nutrient to the air!

Reply to  Milo
May 7, 2023 2:59 pm


Martin Brumby
Reply to  John Hultquist
May 6, 2023 8:56 pm

Seems to me that 100,000 bowhead whales doing what comes naturally must have warmed things a little…

May 6, 2023 5:24 pm

See Arctic sea ice over the last 2000 years
Brennan & Hakim 2022


Arctic sea ice 2000 years.jpg
It doesnot add up
Reply to  ceist8
May 6, 2023 5:37 pm

Oh look. Another hockey stick. The paper might have had some credibility if had demonstrated that its modelling was consistent with historical reports, such as those that are the subject of this article. But it simply disappears up its own orifice. History is the inconvenient truth.

If it disagrees with experiment it’s wrong. That is the key to science.

Chris Hanley
Reply to  It doesnot add up
May 6, 2023 6:38 pm

Like Gergis et al (2014) the authors must have been using Mann’s Hockey Stick-O-Matic (patent pending).

Joseph Zorzin
Reply to  It doesnot add up
May 7, 2023 4:22 am

wow, it’s nice to know that proxies and models can give us sufficient evidence to urgently spend hundreds of trillions of dollars to fix the problem

Tom Abbott
Reply to  It doesnot add up
May 8, 2023 1:24 am

“Oh look. Another hockey stick”

That made me laugh! 🙂

Chris Hanley
Reply to  ceist8
May 6, 2023 6:04 pm

From the Abstract: “Here we reconstruct annual averages of Arctic sea ice coverage for the last two millennia by combining temperature-sensitive proxy records (i.e., ice cores, tree rings, and corals) with climate model simulations using a statistical technique called data assimilation”.
Goodness me, they found physical remains of trees and corals above the Arctic Circle from the past millennia, probably from the Medieval and Roman Warm Periods. 😳
Also this comprehensive Greenland ice core project must be completely wrong.

Reply to  Chris Hanley
May 6, 2023 7:06 pm

That’s a fake graph of the GISP2 ice core data from one location at the top of the Greenland ice-sheet. The data actually ended in 1855.
Data source:


B Zipperer
Reply to  Chris Hanley
May 6, 2023 7:49 pm

As per Chris H (above) your link uses model simulations. From the paper:
“A composite of reconstructed total Arctic sea ice extent anomalies (acquired by assimilating PAGES2kv2 proxy records with a prior drawn from CCSM4 Last Millennium simulation)…”
“PAGES2kv2” Paging Climate Audit! Steve McIntyre has little good to say about the utility of the PAGES2k reconstructions. https://climateaudit.org/?s=PAGES2k

Reply to  Chris Hanley
May 6, 2023 7:59 pm

The GISP2 ice core data is from ONE location at the top of the Greenland ice sheet & the data actually ends in 1855.

data source:


Reply to  ceist8
May 6, 2023 7:56 pm

Another chart from the paper. Arctic sea from 1840

Sea ice Brennan .jpeg
Reply to  ceist8
May 6, 2023 11:18 pm

I wonder how accurate these reconstructions of Arctic sea ice extent are from the distant past, and also what the definition of “Arctic” is. If they mean the entire Northern Hemisphere, then everyone knows how variable that metric is. My own weather/climate here on the Front Range of Colorado is wildly variable depending on things like ENSO, the Pacific Decadal Oscillation, the Arctic Oscillation, etc.

Reply to  ceist8
May 6, 2023 11:31 pm

More FAKE reconstructions from ceist.

How about using real biodata

Arctic Greenland-Sha-17.jpg
Reply to  bnice2000
May 6, 2023 11:32 pm


Reply to  bnice2000
May 6, 2023 11:33 pm

and again

Reply to  bnice2000
May 7, 2023 12:35 am

Why do you call it “fake”. Because you don’t like it? I posted the link to the paper. You posted a graph with no source. That graph is not from Sha et al 2017

It doesnot add up
Reply to  ceist8
May 7, 2023 4:34 am

Does it accord with historical evidence of ice extent?

If it doesn’t match experiment it wrong.

Reply to  ceist8
May 6, 2023 11:34 pm

And from Icelandic sea ice data…

Reply to  ceist8
May 6, 2023 11:36 pm

current levels are ABOVE those of basically all the rest of the Holocene

arctic sea ice holocene.png
Reply to  ceist8
May 6, 2023 11:24 pm

Arctic sea ice from someone who actually knows and isn’t an AGW religious zealot…

Reply to  bnice2000
May 7, 2023 3:57 pm

I’m seeing a lot of source-free graphs with no links to papers.

Tom Abbott
Reply to  bnice2000
May 8, 2023 1:35 am

Turn that ice chart upside down, and it resembles the U.S. surface temperature chart profile (Hansen 1999), with highpoints in the 1930’s and today, and and low points in the 1910’s and the 1970’s.

comment image

Reply to  ceist8
May 6, 2023 11:27 pm

And over the Holocene,, biodata indicates that current levels are only a small amount down from the extremes of the LIA after an extensive increase over that last 2000-3000 years.

Your chart is FAKED from ideology.

arctic rapid freezing.jpg
Dave Fair
Reply to  ceist8
May 7, 2023 11:04 am

PAGES2k? Ha.

Steve Case
May 6, 2023 5:39 pm

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

And we’ve always had sea level rise, hurricanes, tornadoes, droughts & floods. The glaciers of Greenland, Antarctica and others around the world continue calve icebergs into the sea. Wild fires (we used to call them forest fires) have always been with us, and the polar bears are still here.

Tom Abbott
Reply to  Steve Case
May 8, 2023 1:38 am

Nothing to see here. Nothing unusual, anyway.

Scarecrow Repair
May 6, 2023 5:49 pm

Perhaps all that 1600s ice was broken into pieces by the plethora of whales. I mean, the gotta surface to breathe, right, and they gotta break up the ice to surface, right? Right? Then it all drifts out to sea, which it couldn’t as long as it was one solid sheet stretching for miles and miles and locked in place, right?

Peta of Newark
May 6, 2023 6:44 pm

Can I be “the awkward one” and query what the fuss about Sea Ice is really all about

Sea Ice is:

  • Cold
  • Inhospitable to all forms of life
  • Inedible to the point of toxicity
  • It’s only constant is ‘change’….
  • ….it is not and can not be any sort of permanent home

Critters use it to the extent that they’re making use of this otherwise awful, useless and toxic stuff because it’s there and because they can.

This applies to both the polar bears (the hunters) and the seals (the hunted) and I’m sure applies to the things the seals eat/hunt (fishes)
(Fishes need Oxygen and there surely cannot be much of that under a long-lasting or permanent layer of ice)

The best analogy I can think of is of birds sitting on electricity wires or tall buildings.
The overhead wires are convenient for them but if the wires disappeared overnight, it would no great shakes for the birds.
Birds would not go extinct if electricity wires and tall buildings did and the same would apply to polar-bears and seals if Sea Ice became extinct

Basically, the ice creates its own deadsville desert.

If it disappeared and, as Warmists insist, the sun shone down into the water plus some extra Oxygen got into there (CO2 also, wouldn’t the (previously frozen) ocean become a ‘garden’ of productivity.
= Global Arctic Oceanic Greening

The bears and seals would decamp to the nearest dry land and wouldn’t need to expend so much time/energy going hunting across 100’s miles of desert wasteland to find a few scraps of food.
No ice means there’d be an epic farm/garden/supermarket right offshore on their own doorstep.

Especially as the ice is melting because of a warm and nutrient-rich ‘soup’ flowing up from the east coast of North America.
99% of the time, ‘pollution’ a massive food/nutrient resource

iow: Will more people actually stop feeling guilty all the time and stand up to these loud-mouthed, out-of-control, trivia-obsessed children and Stop Appeasing Them in their junk science delusions.
When you do give them an inch, they only ever want more (miles)

just like happened inside the junk science of the GHGE

Joseph Zorzin
Reply to  Peta of Newark
May 7, 2023 4:28 am

nailed it!

I face the same sort of idiots trying to stop all forestry “to save the planet”. They are relentless, fanatic, ignorant, hypocrites who live in nice, large, wood homes loaded with nice wood furniture (often from tropical hardwoods) and loads of paper products.

Ben Vorlich
May 7, 2023 2:05 am

That sea ice map of the Denmark Strait 3rd May 1941 is interesting. On 23rd May 1941 the Bismark and Prinz Eugene passed through the Denmark Strait. The Royal Navy sent two cruisers Suffolk and Norfolk to cover the Strait.
The ice extent in 2012 would have made an undetected passage virtually impossible. 1941 not so much although they were detected.

Then the so called Icelandic “Ice Years”. 1965-1971.

May 7, 2023 3:58 am

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.

I’m shocked that such variability occurs with weather in this day and age-

Climate change killed 40 million Australian mangroves in 2015. Here’s why they’ll probably never grow back (phys.org)

Gulf of Carpentaria sees ‘best fishing in years’ as cherabin, barramundi take over rivers after record floods (msn.com)

Clearly we’re all doomed.

Ireneusz Palmowski
May 7, 2023 12:24 pm

The ice around Svalbard is holding strong this year.
comment image

May 8, 2023 3:26 pm

There are very good sets of maps of ice on the European side from the late 1800s kept by the Danish ice service.

Additionally, the temperature records taken during the voyage of the Fram are very instructive.

May 8, 2023 3:29 pm

Here are the maps, dating from 1850 to 1961. This would be a fun trip for our dear intrepid Willis!


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