Good News For Polar Bears And Seals: New Study Finds Multiyear Arctic Sea Ice Is Getting Thinner

From Polar Bear Science

Dr. Susan Crockford

The fact that multiyear sea ice got thinner between 2018 and 2021 as documented by a new study, is ultimately good news for polar bears: less multiyear ice compared to first year ice is better for all marine mammals in the Arctic. Polar bears and seals, for example, are dependent on the seasonal ice that forms every winter (Atwood et al. 2016; Durner et al. 2009). Multiyear ice is simply too thick for any purpose except as a summer refuge for polar bears (for which land will do just as well) and a platform for maternity dens over the winter, for which thick first year ice will often do just as well (Anderson et al. 2012; Rode et al. 2018).

According to the press release for the new paper (Kacimi and Kwok 2022):

– End-of-season Arctic multiyear sea ice is about 1.5 feet thinner in 2021 than in 2019

– Arctic Ocean sea ice lost one-third of its volume in the past 18 years

– New pan-Arctic snow depth suggests previous estimates of sea ice thickness may have been overestimated

The authors of the paper also emphasized that there had been ‘negligible’ changes in first-year ice over the same period, so it’s only multiyear ice that’s changing.

But don’t forget that old multiyear ice can be very thick indeed: 2-4 metres, sometimes quite a bit thicker, as is the ice north of Greenland which can be up to 20 metres thick.

Sea ice thickness and sea ice age are not the same thing, but sea ice age provides a proxy for thickness. A study published in 2007 found a dramatic change in the age of sea ice in the central Arctic Basin since the mid-1980s. In 1987, 57 percent of the ice pack was at least five years old, and a quarter of that ice was at least nine years old. By 2007, only 7 percent of the ice pack was at least five years old, and virtually none of the ice was at least nine years old (Maslanik et al, 2007). Multiyear ice coverage actually increased between March 2013 and March 2014, thanks to more ice surviving the summer melt season than had survived in the record-breaking summer of 2012. But overall, multiyear sea ice continues to decline in the Arctic (Perovich et al. 2014).

Areas in the central Canadian Arctic where multiyear ice has been largely replace by first year ice in recent years (such as M’Clintock Channel and Kane Basin) have seen polar bear population numbers grow.

References

Andersen, M., Derocher, A.E., Wiig, Ø. and Aars, J. 2012. Polar bear (Ursus maritimus) maternity den distribution in Svalbard, Norway. Polar Biology 35:499-508.

Atwood, T. C., Marcot, B.G., Douglas, D.C., et al. 2016. Forecasting the relative influence of environmental and anthropogenic stressors on polar bears. Ecosphere 7(6):e01370. Doi: 10.1002/ecs2.1370

Durner, G.M., Douglas, D.C., Nielson, R.M., Amstrup, S.C., McDonald, T.L., et al. 2009. Predicting 21st-century polar bear habitat distribution from global climate models. Ecology Monographs 79: 25–58.

Kacimi, S. and Kwok, R. 2022. Arctic snow depth, ice thickness, and volume from ICESat-2 and CryoSat-2: 2018–2021. Geophysical Research Letters 49(5): e2021GL097448. https://doi.org/10.1029/2021GL097448

Rode, K.D., Olsen, J., Eggett, D., et al. 2018. Den phenology and reproductive success of polar bears in a
changing climate. Journal of Mammalogy 99(1):16-26. https://doi.org/10.1093/jmammal/gyx181

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Chaswarnertoo
March 20, 2022 12:29 am

Too many of the murderous buggers around these days, time for a cull.

Brad-DXT
Reply to  Chaswarnertoo
March 20, 2022 12:38 am

I’d rather feed them with the leftist green alarmists. That way we can let nature run its course with less nonsensical predictions of doom and gloom. Less hot air laden with CO2 also.

Emily
Reply to  Brad-DXT
March 20, 2022 9:42 am

I really don’t have a problem with the hunting ban on Polar Bears. The “hunts” for those animals are pretty much so canned that that it is hardly accurate to call it “hunting” and it has apparently been that way for a long time.

Brad-DXT
Reply to  Emily
March 20, 2022 10:37 am

I was suggesting an addition to their diet.
They may suffer from indigestion after their meal but otherwise are not harmed.😁

Alan the Brit
Reply to  Chaswarnertoo
March 20, 2022 1:02 am

I recall reading a few years ago that as of the mid 1960s three were around 5,000 in the Western half of the Arctic, then hunting was banned & the population grew to around 25,000 within a few years. Naturally there have never really been any reliable figures about populations of the Eastern half of the Arctic. Yes they are murderous buggers being the World’s largest known carnivore, & apparently not quite the fluffy, cuddly, fir-balls certain factions would have us believe!!!

rah
Reply to  Alan the Brit
March 20, 2022 4:45 am

I really don’t have a problem with the hunting ban on Polar Bears. The “hunts” for those animals are pretty much so canned that that it is hardly accurate to call it “hunting” and it has apparently been that way for a long time.

‘Tex’ Johnston, one of the greatest test pilots of the golden age of jet aircraft development had been a life long hunter. Though he was the primary test pilot for the B-47 and B-52 bombers he is most famous for doing two barrel rolls with the “dash 80” for a huge crowd during the annual Seattle regatta just after the Blue Angles had done their thing. The “dash 80” was the prototype for the Boeing 707 and the KC-135 tanker.

He had trophies of big game from all over the world. Tigers, Lions, all the big name game. After his first and last Polar Bear hunt some time in the early 60s I think it was, he was so disgusted with the lack of sportsmanship of the “hunt” he sold off his considerable collection of big game hunting firearms and never went after big game again.

Paul S.
Reply to  rah
March 20, 2022 7:37 am

I have a friend who hunted a polar bear a couple of years ago. It was the most difficult hunt of his life. The terrain and the weather was horrendous.

Reply to  Paul S.
March 21, 2022 1:19 pm

Of course it will depend on how you engage in the hunt.

Paul S.
Reply to  Jeff in Calgary
March 21, 2022 10:07 pm

I don’t know of an easy way to engage unless one goes into Churchill with a rifle. My friend was miles from civilization with a bow. Even at that, a rifle would also have been a difficult venture.

Clyde Spencer
Reply to  rah
March 20, 2022 10:45 am

Well, he was obviously hunting bears that had not been properly trained by their mothers. The clever ones get around on three legs so that they can keep their black noses covered by their fourth paw. That way they can’t be seen against the white snow background until they smack you with that paw and open their pink mouth to bite you.

Disputin
Reply to  Alan the Brit
March 20, 2022 4:55 am

“…the World’s largest known carnivore…”
Sperm Whale? Or if you include plankton (debatable) what about the Blue Whale?

Leonard Weinstein
Reply to  Disputin
March 20, 2022 5:41 am

Before you even get to the large whales, the large sharks and killer whales are far larger than the polar bear.

Bill Rocks
Reply to  Alan the Brit
March 20, 2022 8:25 am

World’s largest known terrestrial carnivore

Richard Page
Reply to  Bill Rocks
March 20, 2022 2:05 pm

Well it’s the largest and most dangerous land carnivore but it swims so much it’s classed as a maritime mammal as well!

Elliott Bettman
Reply to  Richard Page
March 20, 2022 8:43 pm

It’s scientific name is “Ursus Marinus”…Marine Bear
The Grizzly is Ursus Horridus.

Richard Page
Reply to  Elliott Bettman
March 21, 2022 8:05 am

And the Polar bear is, on average, larger and more dangerous than the Grizzly. Didn’t I sorta mention that already?

Ben Vorlich
March 20, 2022 12:51 am

Didn’t the DMI change its method of measuring Arctic Sea Ice at the backend of last year?

Steve Case
Reply to  Ben Vorlich
March 20, 2022 1:26 am

Don’t know, but the record of how the IPCC displays it over the last five of its periodic assessment reports is interesting to say the least.

comment image

Scissor
Reply to  Steve Case
March 20, 2022 5:22 am

The known data prior to 1977 ruins the narrative somewhat so it is “disappeared.”

Stephen Skinner
March 20, 2022 1:29 am

“– End-of-season Arctic multiyear sea ice is about 1.5 feet thinner in 2021 than in 2019
– Arctic Ocean sea ice lost one-third of its volume in the past 18 years
– New pan-Arctic snow depth suggests previous estimates of sea ice thickness may have been overestimated”

And so what? Looking at ice core records over the long past shows extraordinary fluctuations and variations. There are NO horizontal lines in this or any data. Peak ice in the Arctic is when temperatures in the lower latitudes are already on they way up to Summer maximums and minimum ice is when temperatures in the lower latitudes are already on they down up to Winter minimums. Multi-year ice in the Arctic is never that old because of the amount of ice that is pushed out of the Arctic basin. Either way I’m sure the Polar Bears will figure out what to do whatever the ice does.

griff
March 20, 2022 1:47 am

Well if the multiyear ice is getting thinner that’s not good news for the ice cap or planet, is it?

Reply to  griff
March 20, 2022 2:23 am

Polar bears don’t like thick ice, you remember ?
There were several periods with no ice cap at all were good, warm times. 😀

Stephen Skinner
Reply to  griff
March 20, 2022 2:32 am

Why? What data or knowledge is there that ice caps need ‘good news’ or that the planet is ‘threatened’ from thinner ice. Perhaps this is possible in a Marvel story? A bit like the ‘Climate Emergency’ which wouldn’t be out of place in a Thunderbirds or Dr Who story?

Chaswarnertoo
Reply to  griff
March 20, 2022 4:13 am

griff. Always on the wrong end of any argument. It’s impressive, really.

MarkW
Reply to  griff
March 20, 2022 7:01 am

Can’t see that it matters one way or another, and bolding my response wouldn’t increase my lack of caring one bit.

The so called positive feedback from the loss of arctic ice never existed, it’s actually a negative feedback. The fact that this is yet another thing the models get wrong is just more proof that they are hopelessly broken.

Clyde Spencer
Reply to  griff
March 20, 2022 10:51 am

that’s not good news for the ice cap or planet,

Why not? Is change always bad? As Susan pointed out (You did read her remarks, right?) it may improve the habit for both seals and bears. You remind me of one of those dolls that has a string to pull. When you do, it says one of just a few recorded remarks. No thinking necessary!

Pat from kerbob
Reply to  Clyde Spencer
March 20, 2022 9:02 pm

Griff isn’t that sophisticated.

griff
March 20, 2022 1:49 am

Meanwhile:

In the south, Antarctic sea ice recently reached its late-summer minimum, dropping below all previous minimum ice extents in the satellite record… . For the first time since the satellite record began in 1979, extent fell below 2 million square kilometers (772,000 square miles), reaching a minimum extent of 1.92 million square kilometers (741,000 square miles) on February 25. 

NSIDC

lee
Reply to  griff
March 20, 2022 2:18 am

oh look summer.

Richard Page
Reply to  lee
March 20, 2022 2:08 pm

Now don’t be cruel, Griffy has just discovered seasons and that they happen all over the world – this is a big day for him!

Reply to  griff
March 20, 2022 3:31 am

How many years passed since the highest extend, 4,5 or 6 years ?
In a warming world ?

Chaswarnertoo
Reply to  Krishna Gans
March 20, 2022 4:13 am

World hasn’t warmed for 7+ years.

Reply to  Chaswarnertoo
March 20, 2022 4:57 am

Some hundreds of a degree, but not in Antarctica, there onlythe peninsula a bit.
Beside that, the warming world I mentioned is the griff-view part of his “record”

Ben Vorlich
Reply to  griff
March 20, 2022 3:49 am

Why is more ice at the poles a good thing? What is the optimum maximum extent for both poles?

By saying reducing Polar Ice is a bad thing it implies there is an optimum. I presume you don’t want the ice to extend into the Watford Gap as it did in the last glaciation, being safe as you’re in the Home Counties? For the North is it the so called “sea ice years” 1965 to 1971 in Iceland?

These drive bys on behalf of your employer are very boring and only show that you don’t have any real knowledge of anything much.

Climate believer
Reply to  griff
March 20, 2022 4:12 am

Oh it’s phone it in Sunday is it? Looks a little chilly out to me…

South pole temp.png
rah
Reply to  griff
March 20, 2022 4:49 am

This after a winter with the coldest 6 months since continuous monitoring began in 1957!

LdB
Reply to  griff
March 20, 2022 7:37 am

In news just in nobody cared.

THOMAS ENGLERT
Reply to  griff
March 20, 2022 4:25 pm

Great news for Antarctic lifeforms! Plankton, fish, penguins, whales celebrate.

Ireneusz Palmowski
March 20, 2022 2:02 am

Cold air masses from the north are reaching the western US again.comment image

rah
Reply to  Ireneusz Palmowski
March 20, 2022 4:52 am

Yep. And it is most likely going to happen again in a couple weeks. Looks like the kind of conditions likely to produce a more active than average tornado season to me.

Tom Abbott
Reply to  rah
March 20, 2022 5:15 am

And it looks like the main tornado track is setting up just a little bit east of Oklahoma this year. We are getting some of the energy here, but most of it so far, is to the east.

The main tornado track is different in different years, and is controlled by how the jet stream configures itself.

rah
Reply to  Tom Abbott
March 20, 2022 5:29 am

That is actually bad news. The further east the higher the ratio of killed relative to the population. I reckon that’s because in less open spaces people are less likely to see one coming or be able to discern what its track is. And fewer people have decent emergency shelters.

Ireneusz Palmowski
Reply to  Tom Abbott
March 21, 2022 11:30 am

Severe frontal thunderstorms in Oklahoma.
https://www.blitzortung.org/en/live_dynamic_maps3.php

Clyde Spencer
Reply to  Ireneusz Palmowski
March 20, 2022 10:57 am

If that is a mixing “ratio,” shouldn’t the assigned colors be unitless instead of “PPBV?”

Ireneusz Palmowski
Reply to  Clyde Spencer
March 20, 2022 3:58 pm

Along with the dry air, Stratospheric Intrusions bring high amounts of ozone into the tropospheric column and possibly near the surface. comment image
https://www.cpc.ncep.noaa.gov/products/stratosphere/strat_int/

Ireneusz Palmowski
Reply to  Clyde Spencer
March 20, 2022 4:02 pm

The air will only begin to mix once a low forms in the southern US.comment image

Editor
March 20, 2022 2:35 am

Prior to DMI tampering with the data last autumn, Arctic sea ice had got thicker in 2021:

https://notalotofpeopleknowthat.wordpress.com/2021/12/10/sea-ice-data-tampering-at-dmi/

Ben Vorlich
Reply to  Paul Homewood
March 20, 2022 3:50 am

I knew I’d read it somewhere, thanks Paul

Tom Abbott
Reply to  Paul Homewood
March 20, 2022 5:17 am

Without data tampering, the climate alarmsts would have nothing alarming to show.

Bob B.
March 20, 2022 3:08 am

If this trend continues, the arctic will be ice-free by 2013. Oh wait…

Bruce Cobb
March 20, 2022 4:20 am

After all these years, Alarmists have never found a better icon than polar bears for pushing their narrative, and they are still being shamelessly used on kids. One photo of a polar bear “stranded” on an ice floe is enough to elicit great sobbing and wailing in kids about their “sad” situation, and how it’s all our fault because Climate Change.

Mark Broderick
Reply to  Bruce Cobb
March 20, 2022 7:30 am

Greenie for lunch !

polar-bear-attack.jpg
Reply to  Mark Broderick
March 21, 2022 8:47 am

It was at the Berlin zoo and apparently she was trying to commit suicide!

Clyde Spencer
Reply to  Bruce Cobb
March 20, 2022 11:00 am

Yes, and the kids don’t realize that an adult bear can swim hundreds of miles with their webbed feet, if need be.

Paul Hurley (aka PaulH)
March 20, 2022 5:52 am

More hungry polar bears will hunt seals. That’s good news for the polar bears but probably not good news for the seals. 😉

Richard Page
Reply to  Paul Hurley (aka PaulH)
March 20, 2022 2:11 pm

It’s very bad news for the slow ones. Standard rules for encountering bears still apply – you only have to outrun/swim your mates, not the bear!

Last edited 6 months ago by Richard Page
Chris Norman
March 20, 2022 6:32 am

As the ice is growing in area they had to make it thinner.
It is all so corrupt.
the claim that they know how thick the ice is is false.

DMacKenzie
Reply to  Chris Norman
March 20, 2022 7:12 am

With LIDAR, you don’t have to find somewhere thick enough to safely set up your boring equipment….so now the ice thickness readings are “thinner”than they were 50 years ago….although subs surfacing at the North Pole sometimes found they were in open ocean…

Brad-DXT
Reply to  DMacKenzie
March 20, 2022 10:43 am

You mean like the USS Skate?

John Hamann
Reply to  Brad-DXT
March 20, 2022 6:02 pm

I can show you a picture of myself at the North Pole along with a British sub and another American sub in 1987…

John Laurent
March 20, 2022 11:27 am

I have a question I would like opinion on. A prominent New Zealand main stream media source, Newshub, has published an article in which climate scientists are saying temperatures in East Antarctica are 40 degrees C above normal for this time of year. They are currently at -10C. When they are normally -50C.
Yeah, what?
At the moment it is early autumn in Antarctica. Surely -50C would be the depths of winter?
Any ideas on this?

Last edited 6 months ago by John Laurent
auto
Reply to  John Laurent
March 20, 2022 12:59 pm

Claim/statement repeated on BBC Radio an hour or two ago.

Auto

Reply to  John Laurent
March 20, 2022 2:23 pm

Newshub gets its info from Griffter Hub?

Richard Page
Reply to  John Laurent
March 20, 2022 2:24 pm

Depends where you are in the Antarctic. McMurdo is usually slightly warmer at around -15 to -20C whilst Vostok and Scott/Amundsen will usually be around -40C. During the coldest part of the year in July – August you’d expect temperatures between -50 and -60C at Vostok and Scott/Amundsen.

Matt
March 20, 2022 1:35 pm

If we could only warm the planet we could thin the ice ourselves. Eventually we could get rid of most of the bears and grow grapes for wine. But, sadly, it appears our activities have little to no effect on the climate, despite the most narcissistic of men wishing otherwise.

John
March 21, 2022 12:46 pm

Why is the ice getting thinner ? Is it getting warmer. ?

Richard Page
Reply to  John
March 21, 2022 1:57 pm

Kilimanjaro springs to mind. Have the average wind speeds changed?

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