Tag Archives: ice-free

Polar bear habitat update for end July 2021 compared to previous years

Here’s a trip down memory lane for Arctic sea ice at the end of July, which as far as I can see provides no evidence that a very low sea ice disaster is in the cards for polar bears this year.

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Alaska waters with no sea ice are not a problem for Pacific walrus or polar bears

One of two alarming headlines that caught my eye this week was the ‘news’ on Monday that the waters off Alaska were now ice-free because of climate change, courtesy a story in the online media outlet Mashable that was later picked up by The Weather Channel and the UK mainstream paper The Independent. In addition, a large number of mainstream news outlets, including the New York Times and Newsweek, have reported that walruses came ashore this year at Point Lay, Alaska two weeks earlier than any year since 2007.

No one claimed this late July onshore movement of walruses was the beginning of the end of walruses but it was still blamed on human-caused climate change because it was associated with the  aforementioned ice loss in Alaska.

Walrus at Point Lay from trail camera in 2015 USFWS

Neither event was truly ‘news’. Moreover, neither an ice-free Alaska in early August or walruses onshore two weeks earlier than 2017 will have any negative impact on local polar bear or walrus populations, whether due to human-caused climate change or natural variation. Well-fed polar bears everywhere are quite capable of going 4-5 months without food in the summer and a few thousand walruses at Point Lay will feed happily from this shore-based haulout for a few days to a few weeks as they have done many summers since 2007 before moving on to other Chukchi Sea beach locations – although the ‘leaving’ events never seem to get any media attention. Walruses will haul out on beaches in Alaska and Russia until the ice returns in October.

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Amstrup & colleages can’t refute my critique of their 2007 polar bear survival model, Part 2

Polar bear specialists Andrew Derocher and Steven Amstrup recently spent inordinate energy trying to refute the opinion piece I’d written for the Financial Post in celebration of International Polar Bear Day last month, ignoring my fully referenced State of the Polar Bear Report for 2017 that was released the same day (Crockford 2018) and the scientific manuscript I’d posted last year at PeerJ Preprints (Crockford 2017).

polar_bear_USFWS_fat Chukchi Sea bear

Their responses use misdirection and strawman arguments to make points. Such an approach would not work with the scientific community in a public review of my paper at PeerJ, but it’s perfect spin for the self-proclaimed “fact-checking” organization called Climate Feedback. The result is a wildly ineffective rebuttal of my scientific conclusion that Amstrup’s 2007 polar bear survival model has failed miserably.

This is Part 2 of my expose, see Part 1 here.
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Problem bear reports confirm Churchill polar bears are in excellent condition

Now that all bears are ashore for the season, the folks at the Polar Bear Alert program in Churchill note in their report for week 7 (21-27 August, 2017) that the bears ashore are in excellent condition (confirming reports on the first bears ashore in July):

Churchill PB reports_week 7_ Aug 21-27_2017_Aug 28

Rather marked contrast to the pessimistic spin on conditions from the field a few months ago:

[yes, a few bears fail to make it through the winter, especially young bears; but that has always been the case — it’s not a sign of human-caused global warming catastrophe]

Last week’s problem bear report also confirmed news from the Churchill Polar Bears website a few weeks ago that showed several images of very fat bears:

Churchill_PolarBears_FAT bear post_21 Aug 2017

See below for last year’s report for week 7 and this year’s report for week 8 (28 August-3 September). Western Hudson Bay polar bears that come ashore near Churchill, Manitoba are starting their third month on land this week, out of the five months or so they have spent ashore in recent years (about 3 weeks more than in the 1980s, no longer than they did in 2004 — conditions have not been getting worse).

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Churchill polar bear reports still showing fewer problems than last year

Churchill, Manitoba’s Polar Bear Alert Program is still reporting many fewer problems with polar bears onshore than it did last year at the same point in the ice-free season (week 5, 7-13 August):

Churchill PB reports_week 5_ Aug 7-13_2017

Compare to week five last year (2016), when bears came ashore in excellent condition:

2016 Aug 8-14_week 5

Although it’s been warmer than average recently (25.4 degrees C yesterday, expected to reach 29 degrees C today and 28 degrees C tomorrow), according to Environment Canada weather records, that’s not even close to an August record-breaker temperature for Churchill. Continue reading

Experts’ vision of an ice-free summer is already wrong & benefitting polar bears

Polar bear populations in most of the Canadian Arctic Archipelago (CAA) must be booming, as they are elsewhere. That’s because the ‘experts’ were even more wrong in their predictions of future sea ice conditions than most people realize: they expected the CAA would remain choked with ice during a ‘nearly ice-free’ summer driven by human-caused global warming.

polar-bear-feeding_shutterstock_sm

Wang and Overland 2012 fig 3b marked

Map presented by Wang and Overland (2012: Fig 3) shows what these experts thought a ‘nearly ice-free’ summer would look like, which they expected to occur by 2030 or so.

Look at the map from Wang and Overland (2012) above, which is what they thought a ‘nearly ice-free’ summer would look like in the year 2030 or so.

Wang and Overland used the same models used by USGS biologists to predict the future survival of polar bears based on habitat loss (Amstrup et al. 2007; Atwood et al. 2016; Durner et al. 2007, 2009). Note the thick ice in the CAA — what USGS experts call the ‘Archipelago’ sea ice ecoregion (denoted by white in the map), indicating ice about 1 metre thick (2-3 feet) — expected to remain at the height of summer in 2030.

[Earlier renditions of sea ice projections (e.g. ACIA 2005) show something similar. The second update of the ACIA released just yesterday (AMAP 2017, described here by the CBC) has prudently included no such firm predictions in their Summary for Policy Makers, just dire warnings of future catastrophe. But see the 2012 update.]

 

The problem is that ice in this region has been largely absent most summers since 2006, even though overall ice extent has been much more extensive than expected for a ‘nearly ice-free’ summer, as I show below.

This is not another “worse than we thought” moment (Amstrup et al. 2007) — this is sea ice models so wrong as to be useless: failed models used to inform future polar bear survival models that got the bears declared ‘threatened’ with extinction in the US in 2008 (Crockford 2017).

It also means polar bears are almost certainly doing much better than recent population counts indicate, since only one subpopulation out of the six in the CAA has recently been assessed. But since polar bear specialists have consistently underestimated the adaptability of this species and the resilience of the Arctic ecosystem to respond to changing conditions, it’s hard to take any of their hyperbole about the future of polar bears seriously. Continue reading

New paper updates lack of trend in W Hudson Bay breakup/freeze-up dates to 2015

A newly-published paper shows that there has been no trend in the time Western Hudson Bay polar bears spent onshore between 2001-2015 due to sea ice conditions at breakup or freeze-up (previously available to 2010 only), despite the marked decline of global sea ice since 2007.

castro-de-la-guardia-et-al-derocher-2017-fig-3-no-caption

Figure 3 from Castro de la Guardia and colleagues (2017) showing freeze-up and breakup dates and ice-free days 1979-2015 for Western Hudson Bay. Figure with caption, copied below, explains symbols.

Previously, a 2007 paper by Eric Regehr and colleagues for WHB bears up to 2004, which was used to support the US bid to list polar bears as ‘threatened’ with extinction, concluded that between 1984 and 2003, bears were spending 3 weeks longer onshore than they did in the 1980s.

The big news from Castro de la Guardia et al. (2017) is that polar bears spent longer onshore from 1979-2015 by … 3 weeks. That is, no change from the situation in 2004. Wow!

Note the population size of the entire WHB subpopulation has also not declined since 2004 and is currently estimated at about 1030, based on a 2011 aerial survey (Stapleton et al. 2014).

Thanks to Andrew Derocher for the heads-up tweet.

From the abstract (my bold):

We found that the ice-free period in this region lengthened by 3 ± 0.8 wk over the period 1979−2015. Polar bears migrated onshore 2 wk earlier and offshore 1 wk later in the period 2005−2015 than in 1980−1989.

Here is the region in question, illustrated by Fig. 1 from the paper:

castro-de-la-guardia-et-al-derocher-2017-fig-1a-locationThe significant information contained in this paper is breakup and freeze-up dates and length of the ice-free period data for 2010-2015, which has been unavailable until now. More excerpts and comments below, including Figure 3 with its caption. Continue reading

Hudson Bay could be ice-free in winter within 5-10 years, says seal researcher

Ringed seal biologist Steven Ferguson, in a statement to a reporter from the Winnipeg Free Press, made one of the boldest predictions I’ve ever heard:

crystalball_468x317_predictions_sq

 

“Hudson Bay could experience its first free winter within 5-10 years.”

You heard it here, folks. It appears Ferguson thinks Hudson Bay was never ice-free in winter even during the Eemian Interglacial, when the Bering Sea was ice-free in winter – something that has not come close happening in recent years (Polyak et al. 2010:1769).

Sounds like a bit of ill-advised grandstanding to me.

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Polar bear habitat this fall shaping up fast – more like 2010 than 2007

Arctic sea ice tied 2007 for extent at the September minimum less than 3 weeks ago but with the refreeze proceeding much faster than 2007, seals will soon be returning to the ice edge and polar bears will be back to feeding like they did in 2010.

sea-ice-at-28-sept_2016_vs-2007_2012_5-point-0_nsidc-interactive

Sea ice extent less than 5.0 mkm2 lasted less than 6 weeks (23 August – 28 September), according to NSIDC.

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USGS promotes another flawed polar bear model: GHG emissions still “primary threat”

It’s still based on the same flawed ecological premise as all previous models – it assumes that sea ice was a naturally stable habitat until human-caused global warming came along. It also uses slight-of-hand maneuvers to correlate declining summer sea ice and declining polar bear population numbers.

PolarBearCV1_USGS_2009

Just because they keep repeating the same hype doesn’t make it true.
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