Dr. Susan Crockford
According to Polar Bears International, the “3rd-earliest” breakup date for Western Hudson Bay was caused by a “record breaking” heat wave in May. Western Hudson Bay sea ice hit the 30% coverage threshold used by PBI to define “breakup” on 17 June this year, prompting speculation about potential future impacts on polar bear survival should breakup come even earlier.
“This year’s break-up date of June 17 is the 3rd earliest in the 45 years of satellite-based sea ice data from Western Hudson Bay, after 2015 and 2003.” [Flavio Lehner, PBI]
17 June 2023 is day 168 on the Julian calendar used to graph the data in the image included in the PBI essay (see copy below). However, the data point for 2003 is about three days earlier, on day 166 (14 June) and the point for 2015 is on day 152 (1 June).
If “record-breaking” heat caused this year’s early ice retreat, what caused the ice to retreat more than two weeks earlier in 2015? May was warm that year along the west coast as well but obviously not “record-breaking” warmth, because the records were broken this year. In fact, whatever warmth that occurred only affected ice melt in the western sector, while very thick ice over the rest of the bay resisted melt and allowed bears to stay out many weeks later than usual.
Sea ice breakup in 2023
Closest in my archive to 17 June is 19 June (but 15 June isn’t much different along the western portion so it probably didn’t change much between the 17th and 19th). Note how much ice is missing in the eastern bay as well.
Sea ice breakup in 2015
Compare the above to 1 June 2015 (below), when the same 30% ice coverage threshold was apparently reached. Note this is 30% of the Western Hudson Bay region in particular, not Hudson Bay in general. In fact, the ice melt pattern in 2015 was quite unusual, with lots of open water in the western sector but thick, solid ice everywhere else that resisted melt. Despite early melt in Western Hudson Bay, at August 13, only 1992 had more ice remaining in the bay overall.
At 20 July 2015, more than half of collared Southern Hudson Bay bears were reported still far out on the ice. On the same date (see tweet below), polar bear specialist Andrew Derocher noted that only 2 out of 9 collared bears had come ashore (one way over in Hudson Strait), when the prediction based on 30% WH ice coverage should have seen them all onshore by 30 June (Cherry et al. 2013):
According to Cherry et al. (2013):
“Throughout the study, bears arrived ashore a mean of 28.3 day (S.E. = 1.8) after 30% ice cover.”
Thus, according to Cherry’s criteria, this year we should expect most bears to be onshore in WH by 15 July. However, as of 27 June, only 6 of Andrew Derocher’s tagged bears were onshore and the rest (27 of them) were still out on low concentration sea ice (see map below). Several of them are way out in the middle of the bay. Time will tell whether they will all head to shore over the next two weeks or if some will linger a few weeks longer on bits of remnant ice, as seems to be the usual pattern in recent years.
All this suggests that the 30% ice coverage metric may not be an especially good predictor of polar bear behaviour. That’s not just my opinion: one of Derocher’s students undertook an analysis that came to a similar conclusion.
Her more recent paper (Castro de la Guardia et al. 2017) found that a threshold of 50% ice coverage over WH was the best predictor of when polar bears come ashore in the summer:
“The most suited definition of breakup was the 50% ice concentration. There was a high positive correlation (r2 > 0.9, p = 0.07) between migration onshore and breakup from 2006 to 2009, with polar bears migrating onshore approximately 20 d after breakup.” [Castro de la Guardia et al. 2017, pg. 230, my emphasis]
If this more recent study, which uses more data and a 50% ice coverage threshold to define breakup, is the best predictor of when polar bears come ashore, why are PBI representatives using a 30% threshold? They don’t say, or even mention that another method has ever been used to assess when polar bears come ashore. Nor do they mention that in general, since 2015 at least, some bears simply haven’t been behaving as expected, and have been staying out on highly degraded ice late into summer. Odd, that.
Problem Bears Onshore
The first real Churchill Polar Bear Alert Report came out (for week 2 of the summer season, 19-25 June), with only a few bears onshore close to town requiring encouragement to hang out further afield.
References
Castro de la Guardia, L., Myers, P.G., Derocher, A.E., Lunn, N.J., Terwisscha van Scheltinga, A.D. 2017. Sea ice cycle in western Hudson Bay, Canada, from a polar bear perspective. Marine Ecology Progress Series 564: 225–233. http://www.int-res.com/abstracts/meps/v564/p225-233/
Cherry, S.G., Derocher, A.E., Thiemann, G.W., Lunn, N.J. 2013. Migration phenology and seasonal fidelity of an Arctic marine predator in relation to sea ice dynamics. Journal of Animal Ecology 82:912-921. http://onlinelibrary.wiley.com/doi/10.1111/1365-2656.12050/abstract
PB International!?
The same group that told news crews that there was insufficient sea ice when all of the bears were already out on the ice hunting seals last Autumn and visitors could easily see sea ice and fast ice?
Do tell…
Its difficult to keep a narrative afloat in a changing sea (ice).
Meanwhile, Baffin Bay is about the same as 2022, and the Greenland Sea, Central Arctic, Laptev Sea, Kara Sea, Chukchi Sea are all well above the last 5 years.
It is just weather patterns.
Arctic and Antrctic sea ice extents both currently millions of km2 below what they would normally be at this time of year is ‘just weather patterns’? Oh….
WRONG yet again…
Arctic sea ice extent is higher than it has been for nearly all of the Holocene.
It is also above the 15 year average.
If you are stupid and ignorant enough to take the period starting from the extreme high in 1979…
… it just proves you are not interesting in facts, and are only interested in promoting the lies and deceits of the AGW agenda.
Oh…
Not sure how we explain this, then.
Pretty much on average since 2004..
Above the 15 year mean
… and WAY above the Holocene average.
Way above Holocene average, and above the Holocene range of extents
It is actually in the top 5-10% of the last 10,000 years.
So much sea ice up there.
Did you know that the extent in 1979 was nearly up to the extremes of the LIA..
.. Sea life is only just starting to return after being driven away by those extreme sea ice levels.
But I don’t support you care one jot about Arctic sea life…
… or any life on the planet in fact…
Being a CO2-hater, it must be so difficult keeping up the pretence.
MASIE also has the current extent above the 15 year mean
Or this….
You’re Right. Simply cannot be anything to do with this:
So let’s all panic.
“Found” and “new”. One of these is not necessarily like the other.
“There are many places on Earth where fire meets ice. Volcanoes located in high-latitude regions are frequently snow- and ice-covered. In recent years, some have speculated that volcanic activity could be playing a role in the present-day loss of ice mass from Earth’s polar ice sheets in Greenland and Antarctica. But does the science support that idea?
In short, the answer is a definitive “no,” though recent studies have shed important new light on the matter. For example, a 2017 NASA-led study by geophysicists Erik Ivins and Helene Seroussi of NASA’s Jet Propulsion Laboratory added evidence to bolster a longstanding hypothesis that a heat source called a mantle plume lies deep below Antarctica’s Marie Byrd Land, explaining some of the melting that creates lakes and rivers under the ice sheet. While the study may help explain why the ice sheet collapsed rapidly in an earlier era of rapid climate change and why it’s so unstable today, the researchers emphasized that the heat source isn’t a new or increasing threat to the West Antarctic ice sheet, but rather has been going on over geologic timescales, and therefore represents a background contribution to the melting of the ice sheet.”
https://climate.nasa.gov/explore/ask-nasa-climate/2982/fire-and-ice-why-volcanic-activity-is-not-melting-the-polar-ice-sheets/
Right. So red hot magma beneath does nothing, but “back radiation” from 42 thousandths of 1% of the atmosphere melts ice where the air temperature seldom gets above -25ºC. Got it.
One source is demonstrably changing, trans increasing [CO2]…..
“ trans increasing “
Oh, so CO2 is now changing gender.
How leftist of it !
Not only that, but at the CO2 emission frequency, that is equivalent to a Wein’s temperature of some -80C (iirc)
It requires super-cooled sensors to even register it.
And anyone that would “ask NASA” about climate, must have rocks in their head, or be a major shill for the AGW scam.
Hey, BOB, who is going to decommission all the wind and solar crap?
You know the useless stuff that just wastes massive amounts of money?
Your big crybaby act was about oil well decommissioning, BUT oil and natural gas lifted the US from semi poverty to incredible wealth, so if EVERYONE ends up pitching in on decommissioning, at least EVERYONE benefited from the output. No ONE benefits from unreliables, except crony capitalists and the politicians they pay to put in office.
Still using a comparison to 81-2010, instead of the more current, and thus correct, 92 to 2020.
@ssh@t.
Yes, just weather patterns. According to the Met Office, temperatures in the Arctic have been average or below average throughout May and June after a mild Winter. What was significant was that May was a ‘particularly unsettled, cyclonic month’ with a succession of powerful storms entering from the Western Siberia region. As I have previously mentioned (on another topic) Antarctica saw an unusual low pressure system enter the Amundsen Sea, bringing warmer air that inhibited sea ice formation but in other areas sea ice exceeded the average, although the overall sea ice extent was lower. Weather, FN. And if you had bothered to do even the most basic research you’d have discovered exactly the same thing. Weather dominates sea ice extent in the Arctic and Antarctic, not temperature – unusually warm winds (like this year in the Antarctic) will prevent sea ice formation whilst storms later on will cause early break-up and dispersal of sea ice (this year and occasional previous years going back several decades in the Arctic). This is not too unusual – we’ve seen many instances in the past when storms have caused early break-up of sea ice, I’ve even pointed them out in previous years. Blinkered vision is one thing but wilful blindness is unforgivable, FN – I’m disappointed, I thought you were better than that.
I thought we weren’t allowed to trust the Met Office?
Their endless fascination with the minutae of temperature – using hundredth’s of a degree to hype an alarmist narrative – I find to be ridiculous. Weather patterns, on the other hand, they still do relatively well. Just check and double check their temperatures – especially when they start adding improbable decimal places.
Antarctic sea ice extent more than 2 million square kilometres below average for this date. That’s some weather pattern.
Yes it is – I did mention it was an unusual weather pattern for the time of year, didn’t I?
I don’t think FN understands the word “Weather”
It is not part f his paid AGW mantra.
Like many climate enthusiasts, when he sees ‘weather’ and ‘climate’ he just thinks ‘temperature’ – it’s badly blinkered vision.
Rusty do you promise when the natural variability results in higher than average sea ice extent some year soon that you’ll demand more CO2 emissions to counter the worrisome trend?
I am sure that you won’t. Don’t be so boring.
Based on your out of date chart?
Update to the most current 30 year period, 1991 to 2020, then come back and see us.
@ssh@t.
Yes Rusty, just weather. Go to the pub, tip a couple of pints, forget your propaganda for a while.
“tip a couple of pints”
Probably not a good idea to mix alcohol with all the other crap he is taking. !
It would be interesting to see that first graph, for just this century.
Looks to me like a major step change around 1998, and a spike in 2015.
I wonder what could have caused them. 😉
Meanwhile not far away (~ 2 inches on the map )
Greenland is increasing SMB
http://polarportal.dk/fileadmin/polarportal/surface/SMB_curves_LA_EN_20230707.png
Greenland doesn’t count dude. It doesn’t support the narrative.
“It doesn’t support the narrative.”
It is very difficult for them to find anything real that does.
That is why they are just “fabricating” junk-non-science on a very regular basis.
I think it’s a combination of factors – a mild winter probably inhibited thick sea ice formation then an unusually stormy May (even with average or below average temperatures across the region) broke up much of the thinner sea ice leading to a lower sea ice extent. The Kara and Chukchi seas, which bore the brunt of the storms, appear to have a much lower sea ice extent than average. Even without the storms, the mild winter meant that sea ice this year would likely not have broken records but it might have been more extensive.
“The Kara and Chukchi seas, which bore the brunt of the storms, appear to have a much lower sea ice extent than average.”
Not according to MASIE. https://nsidc.org/data/masie/explore-region
Region 5 (Kara) is above the last 4 years.
Region 2 (Chukchi) is also above the last 4 years.
Now they are. What were they like during May when the storms hit – looking at that graph (which doesn’t appear to go back into May) they come from a low extent then to a higher extent of sea ice.
I’ll see if I can find the time to update my charts of each region since MASIE started
(not updated since 2021.. lazy me)
But I’m in the middle of a large project in the shed. 😉
That’d be interesting to see. It would take some of the ambiguity out of what’s been happening since May. Take your time though – it’s not urgent; the Arctic ice isn’t going anywhere.
Haven’t done the graphs…
… but I updated the data for Kara, and it shows a period from May 22 to June 23 when the 2023 level was below the
1517 year average.I think that supports your point. 🙂
The graph.. just for Kara Sea, back to 2009
Disclaimer… Done quickly .. hopefully no errors 😉
Oops ignore that one, Something went wrong with horizontal axis.
This one shows the horizontal axis as “day of year”.
Sea ice, just like atmospheric temperatures, has shown no significant trend in the 21st Century. Certainly nothing like those from the UN IPCC CliSciFi climate models.
That’s why I’d like to see the first graph in the post, just for this century.
Looks to me like there would be very little trend.
Looks like a step change in 1998.. then basically level.
Do take a look at the Danish website ocean.dim.dk/Arctic etc for their Arctic north of 80 north temperature graphs from 1958 to now. Never does the melt mid June to refreeze in August exceed 2 degsC. 2015 looks pretty normal with golly gosh a spike to minus ten C in April! Nothing unusual about 2005 either except that blimey a spike to minus 15C in January. This year very normal with some warming (huh!) spikes to minus 20 early in the year. So where does this Arctic warming scare come from? Or have I missed something?
Regardless of the truth about the polar ice- the vast majority of humans are not going to sacrifice their life style (meager for most) to get MORE ice in those regions.
Going out on a limb here, but I’m pretty sure the polar bears don’t read any of the “studies”, and merely go about their business regardless of the difference in sea ice cover. Since climate consists of weather patterns averaged of a large number of years (i.e. more than 1!), I doubt any of the extant bears will have to drastically alter their behavior (or succumb) because of the mythological anthropomorphic “climate change”.
As I noted, above, nothing much has changed for the bears during the 21st Century.
This year’s break-up date of June 17 is the 3rd earliest in the 45 years…
That’s like saying it’s the third fastest 100 meter in Olympic History. It doesn’t mean anything. It’s insignificant. No one remembers the third fastest Olympic runner. But…well..it’s the media and journalists we’re dealing with here. Almost everything they say is insignificant and quickly forgotten though it somehow sounds important to them.