Susan Crockford
New evidence indicates that Arctic areas with the thickest ice today probably melted out every year during the summer for about 1,600 years during the early Holocene (ca. 11.3-9.7k years ago), making the Arctic virtually ice-free. As I argue in my new book, this means that polar bears and other Arctic species are capable of surviving extended periods with ice-free summers: otherwise, they would not be alive today.
Money quote: Here we show marine proxy evidence for the disappearance of perennial sea-ice in the southern Lincoln Sea during the Early Holocene, which suggests a widespread transition to seasonal sea-ice in the Arctic Ocean. [Detlef et al. 2023: Abstract]
An illustration of the Last Ice Area in the Arctic, which is currently covered in perennial ice (2-4m thick) that does not melt out every summer (Moore et al. 2019) from the press release for a paper by Newton and colleagues (2021):
The Lincoln Sea discussed in the new paper is withing the LIA, between Greenland and Ellesmere Island, as shown below.
The short animation below shows sea ice thickness from 1979-2022 in the Arctic at the height of summer within the Last Ice Area was ca. 2.5-4.0m thick, which is thinner and less extensive than it was in the 1980s (when it was 4-5m thick or greater). In other words, perennial ice is not gone yet.
Loss of thicker September sea ice from 1979 to 2022…
Note that I have masked out sea ice < 1.5 meters in order to emphasize the decline of the (relative) thicker ice. Data from PIOMAS. You can compare this animation with a more realistic version here: https://t.co/qXpJKsAzX9 pic.twitter.com/Ki6vSuXNkT— Zack Labe (@ZLabe) October 11, 2022
Figure S5 from the Detlef paper (below) shows that reduced sea ice during the early Holocene was widespread, with evidence for seasonal ice in the Barents, Beaufort and Laptev Seas as well as NE Greenland and the Lincoln Sea between northern Greenland and Ellesmere Island.
Evidence from several sources indicates that the Eemian produced conditions even warmer than documented during the early Holocene and they lasted longer, as explained in the excellent summary by Leonid Polyak and colleagues (2010). During the early portion of the Eemian at least (ca. 130-120k years ago), summer temperatures were about 5–8 degrees Celsius warmer than today and the Arctic was virtually ice-free. At about 120k years ago, there is evidence from Finland and the Norwegian Sea off Norway that a cooling event lasting 500-1,000 years broke the long stretch of warmth (Helmens et al. 2015).
Not only did polar bear survive these two extended periods when ice-free summers prevailed, but the Eemian warm summers came only about 10,000 years after the bears arose as a unique species. This makes polar bear survival through the Eemian even more impressive than most scientists acknowledge. The polar bears’ ability to store excess energy as fat in the spring and metabolize it later when needed must have been fine-tuned by natural selection during this challlenging time (Crockford 2023).
The fact that polar bears survived both extended periods of ice-free summers means that their computer-generated prediction of extinction in a slightly warmer world are groundless.
References
Crockford, S.J. 2023. Polar Bear Evolution: A Model for How New Species Arise. Amazon Digital Services, Victoria. https://www.amazon.com/dp/1778038328
Detlef, H., O’Regan, M., Stranne, C. et al. 2023. Seasonal sea-ice in the Arctic’s last ice area during the Early Holocene. Communications Earth & Environment 4:86. https://doi.org/10.1038/s43247-023-00720-w
Helmens, K.F., Salonen, J.S., Plikk, A. et al. 2015. Major cooling intersecting peak interglacial warmth in northern Europe. Quaternary Science Reviews 122:293-299. http://dx.doi.org/10.1016/j.quascirev.2015.05.018
Moore, G.W.K., Schweigher, A., Zhang, J. et al. 2019. Spatiotemporal variability of sea ice in the Arctic’s Last Ice Area. Geophysical Research Letters 46(20):11237-11243. https://doi.org/10.1029/2019GL083722
Newton, R., Pfirman, S., Tremblay, L.B. et al. 2021. Defining the “Ice Shed” of the Arctic Ocean’s Last Ice Area and its future evolution. Earth’s Future 9(9):e2021EF001988. https://doi.org/10.1029/2021EF001988
Polyak, L., Alley, R.B., Andrews, J.T., et al. 2010. History of sea ice in the Arctic. Quaternary Science Reviews 29:1757–1778. https://doi.org/10.1016/j.quascirev.2010.02.010
As polar bears are closely tied to the requirements of seal whelping, winter/early spring ice needed for seal haulout and breeding, and polar bear predation are critical.
Any period when the seals are not whelping would seem to be irrelevant.
I’m not convinced. Polar bears only need seals to haulout on ice because the place is covered in ice. Without ice, seals will haulout on beaches, which will do polar bears just as well.
How long can the climate enthusiasts insistence that a bit less Arctic ice will be dangerous for the Polar Bears last in the face of mounting evidence to the contrary?
How long have you got?!
Not as long as I’d like. Probably not long enough to see the end of this insanity (but I can hope).
The Ministry of Truth directs the Puppet Legacy Media to ignore the evidence to the contrary and the end of days beat goes on.
Indeed. They, having their right hemispheres ablated by higher education, value theory over evidence. That makes them overconfident, removed from reality, and unable to believe they might be wrong, let alone correct wrong beliefs. In fact, their divorce from reality mimics schizophrenia. link
Also, they know almost nothing about anything even a tiny bit outside their silos.
With regard to polar bears, there is Ian Stirling. I’ve met him and worked with his people. I have profound respect for him. My joke is that he knows half the polar bears in Canada on a first name basis. He is convinced that the loss of ice in the arctic dooms polar bears. I’ve seen no evidence that he’s going to change his mind, no matter how much evidence piles up.
The only real polar bear extinction that occurred in the recent past didn’t have anything to do with the Arctic at all.
“With the announcement of the planned closure of Leicester’s Fox’s Glacier Mint factory, the fate of the sweets’ iconic stuffed polar bear has come into question.”
https://www.leicestermercury.co.uk/news/local-news/what-happened-peppy-foxs-glacier-2595309
Maybe Al Gore got the idea from Fox’s Glacier Mints?
That is great, now I can add another science paper to my growing list in the thread of Little to no summer ice in the arctic.
LINK
“As I argue in my new book, this means that polar bears and other Arctic species are capable of surviving extended periods with ice-free summers: otherwise, they would not be alive today.”
Any idea of the population size during those periods- compared to whatever it’s maximum is believed to be in recent centuries?
How about during glacial maxima? (is that a word?)
Regardless, they’re apparently resilient as a species- that’s what counts.
Not really. One study found evidence of a genetic “bottleneck” less than 45k years ago (Lindqvist et al. 2010), which would fit with a glacial maxima decline. The only genetic study that attempted to answer your precise question also shows a sharp decline in population size during the last ice age (LGM), although they provide no precise numbers. Keep in mind, however, that these researchers (Miller et al. 2012) also concluded that polar bears evolved from brown bears 4-5 million years ago, which is simply implausible given that the oldest brown bear fossils are only about 660 THOUSAND years old. I find that geneticists rarely check to see if their conclusions make sense compared to other evidence. Susan
Susan,
I’m surprised that brown bears may only be 660K years old. I don’t know how long black bears have been around but I presume for millions of years. If that’s the case I would think there is a niche for the much bigger brown bears based on their predatory habits- so I would think must have been around longer than that- but this is just a wild guess. I’m not a biologist or ecologist, just a field forester who likes black bears. But until the fossils are found we shouldn’t assume the age of the species.
It doesn’t really work that way, Joseph – there are bear and bear-like fossils that indicate an evolutionary pathway going back millions of years, but the modern Brown Bear hasn’t been around for the whole time. Us, Homo Sapiens Sapiens, probably isn’t even as old a species as the Brown Bear (or possibly even the Polar Bear) but our ancestral species go back further. We can only tell the story that the fossil remains show us – if scientists indulge in wishful thinking, wistful make-believe and making stuff up without proof then they are no longer scientists but fantasists and there are far too many of them around already.
I suspect that polar bears go to where the seals are. If there is no ice, where do the seals go? There you will find the bears.
Right, and that’s always made me wonder why there’s this faux freak-out over sea ice and polar bear populations. The bears in Alaska do what bears do here in Colorado when they want a quick snack- raid garbage cans/bins/dumps…
Wild guess but I should think the seals must come to land if there is no ice and the PBs could hunt them on land? Maybe the seals would go up rivers a ways- then on to land but not far from the water so they can get away quick. My wild guess is the less ice the better for a richer ecosystem- for seals and PBs.
Joseph, I think you’re confusing no ice during the summer with no ice at all. Even with ice-free summers for 1,600 years, there would still have been ice during the spring when seals need the ice for giving birth and mating (and thus providing food for polar bears).
Polar bear specialists have been using climate models to insist that if conditions are such that sea ice in the High Arctic in summer declines to near zero, it means that virtually all polar bears (no matter where they live) will be forced onto land, without food, for 6 months or more and will die. Clearly, this did not happen in the early Holocene because polar bears still exist.
An elegant argument that makes a strong case.
Well, duh, they are bears. Apex predators and whatnot.