Tag Archives: polar bears

Svalbard polar bears doing fine with much less sea ice say Norwegian biologists

“…despite the loss of good denning areas and a shrinking habitat for hunting, Svalbard’s bears seem to be doing fine.…The sea ice season is now several months shorter, and the ice edge typically lies several degrees further north than what was normal 20-40 years ago….Polar bears can survive long periods without food, provided they have accumulated a good fat reserve during the few months in spring and summer when sea ice is present, and seals are abundant.” [Jon Aars, Norwegian Polar Institute, 2018]

lying bear shutterstock_244419640_cropped_web size

Jon Aars from the Norwegian Polar Institute has written an update on the status of Svalbard polar bears for the general public (The Barents Observer, 8 January 2019, republished from a story published by The Fram Centre in their newsletter: Population changes in polar bears: protected, but quickly losing habitat).

franz_josef_land_location_wikipedia

Read the whole thing below (original has awesome photos). It reports the truth of the current situation with the usual caveats about what might happen decades into the future. Continue reading

Hudson Bay polar bear habitat is highest in more than two decades for this time of year

More ice in Hudson Bay and adjacent regions than we’ve seen at this time of year for more than two decades: not since 1993 has there been as much polar bear habitat in the 2nd-last week of November.

Sea ice Canada 2018 Nov 22

The anomaly chart for this week is almost all blue:

Hudson Bay weekly departure from normal 2018 Nov 19

Other years back to 1994 had much less ice for the 2nd-last week in November, as the charts below show. Colour charts are only available from 2004.

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Arctic sea ice habitat for polar bears is like a big pond that dries up partially in summer

What’s a good analogy for sea ice as essential polar bear habitat? Biologist Andrew Derocher claims that the soil in a forest is appropriate, because without the soil you can’t have the forest ecosystem. However, that’s a specious comparison because the amount of soil in a forest does not change markedly with the seasons the way that Arctic sea ice does.

polar-bear-arctic-ice_21-aug-2009_patrick-kelley-us-coast-guard.jpg

A much better analogy is a big pond that dries up a bit every summer. The amount of habitat available to sustain aquatic plants, amphibians and insects is reduced in the dry season but many species have special adaptations for surviving reduced water availability. For the rest of the year, however, the pond provides an abundant and non-limiting habitat for all the creatures and plants that live there.

Beaver pond USFWS

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New ice on Hudson Bay a week earlier than 2017: another early freeze-up ahead?

Last year, an early freeze-up of Western Hudson Bay sea ice almost ruined the Polar Bear Week campaign devised by Polar Bears International to drum up donation dollars and public sympathy for polar bear conservation. Many bears were on the ice hunting by 7-8 November in 2017 before the celebratory week was done (the average date that bears left the ice in the 1980s): sea ice charts suggest the same may be happening this year.

Polar bears off Churchill_2000-11-20_wikipedia

Ice is forming along the Hudson Bay coast more than a week earlier than it was last year (barely discernible on the map below but detailed ice charts show it clearly), consistent with early build-up of ice in the Canadian Archipelago, East Greenland, and Foxe Basin since mid-September.

Sea ice Canada 2018 Oct 23

The question is: will the ice continue to build over the next few weeks or get blown offshore? See the ice charts below for this year and 2017.
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Now at least 10 years with sea ice at 2050-like levels yet polar bears are still abundant

We’ve hit the seasonal Arctic sea ice minimum for this year, called this morning by US NSIDC for 19th and 23rd of Septmeber: 4.59 mkm2, the same extent as 2008 and 2010. This is not a “ho-hum” year for polar bears: it means that since 2007, they have triumphed through 10 or 11 years1 with summer ice coverage below 5.0 mkm2 —  levels that in 2007 were expected to cause catastrophic declines in numbers.

polar-bear-on-thin-ice_21-aug-2009_patrick-kelley-us-coast-guard.jpg

Summer sea ice below 5.0 mkm2 were not expected to occur until about 2050, according to 2005/2006 sea ice models and polar bear specialists at the US Geological Survey (USGS). Polar bear survival models predicted 2/3 of the world’s polar bears would disappear when ice levels reached this threshold for 8 out of 10 years (Amstrup et al. 2007, 2008; Hunter 2007) but polar bears have been more resilient than expected (Crockford 2017, 2018; Crockford and Geist 2018). In fact, in many areas (like the Chukchi Sea, Barents Sea and Foxe Basin) polar bears are thriving despite dramatic declines in summer sea ice coverage (Aars et al. 2017; ACSWG 2018; Peacock et al. 2013; Regehr et al. 2016; Stapleton et al. 2016).

The sea ice models used to support the addition of polar bears to the US Endangered Species List as ‘threatened’ with extinction suggested sea ice levels from 3-5 mkm2 would not occur unti mid-century, yet they dropped before the ink was dry on the 2007 USGS Reports (ACIA 2005; Hassol 2004; Holland et al. 2006; Solomon et al. 2007; Zhang and Walsh 2006).

The ice extent charts from the University of Bremen (below) show ice that’s 50% concentration or greater at the date of the seasonal minimum (19th September): what polar bear specialists define as preferred habitat (Amstrup et al. 2007).

arctic_amsr2_visual_2018_sept_19.png

Compare the minimum shown above to the coverage predicted for 2050 and to coverage at the minimum in 2012 (the NSIDC image is here):

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Tracking polar bears in the Beaufort Sea May and June updates

At the end of June, there were nine bears remaining from the original 14 that were tagged with glue-on ear transmittors in April 2018 near Kaktovik, Alaska by US Geological Survey biologists.

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Below is the June 2018 tracking map (high resolution image is here):

Beaufort tracking USGS bear-movements-June 2018 sm

Original caption: “Movements of 9 satellite-tagged polar bears for the month of June, 2018. These bears received satellite eartag transmitters in 2018 on the spring-time sea ice of the southern Beaufort Sea. Polar bear satellite telemetry data are shown with AMSR2 remotely-sensed ice coverage for 30 June, 2018.”

See the close-up for June 2018 below:

Beaufort tracking USGS bear-movements-June 2018 closeup

As ear tags are notoriously short-lived, there may not be any remaining by the end of July but if there are, I will post the tracks. The map for May 2018 is below.
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Less Svalbard polar bear habitat during the early Holocene than now

Svalbard in the western Barents Sea has recently had less sea ice extent than it had in the 1980s, especially in the west and north, but this is not unprecedented.

Svalbard polar bear_Aars August 2015-NP058930_press release

New evidence from clams and mussels with temperature-sensitive habitat requirements confirm that warmer temperatures and less sea ice than today existed during the early Holocene period about 10.2–9.2 thousand years ago and between 8.2 and 6.0 thousand years ago (based on radio carbon dates) around Svalbard. Barents Sea polar bears almost certainly survived those previous low-ice periods, as they are doing today, by staying close to the Franz Josef Land Archipelago in the eastern half of the region where sea ice is more persistent.

As this sea ice chart for 18 April 2018 shows, ice this month has been virtually absent from the west and north coasts of the Svalbard Archipelago, while Franz Josef Land to the east is surrounded by highly concentrated pack and land-fast ice.

Barents Sea ice 2018 April 18 NIS

From a new paper by Jan Mangerud and John Svendsen (2018) [my bold]:

Svalbard, located between 74° and 81°N, is the warmest place on Earth at this latitude (Drange et al., 2013). This is because of the North Atlantic Current and large-scale atmospheric circulation which transport warm water and air masses from lower latitudes northwards across the Atlantic and along the coast of Norway to Svalbard (Figure 1). Yet, during the Holocene Thermal Maximum, the climate of Svalbard was considerably warmer than at present.

The transition from Younger Dryas cold to Holocene Thermal Maximum warm conditions took place very rapidly, according to records from nearby Greenland (Taylor et al. 1997), warming in “steps” of about five years each over a period of about 40 years. This was at least as fast, if not faster than, recent Arctic warming between the 1980s and 2015. And since polar bears of the Barents Sea and adjacent Arctic areas appear to have survived this change to Holocence Thermal Maximum conditions, it challenges the notion that recent warming has been (or will be) too fast to allow polar bears to survive without huge changes in their present distribution (Amstrup et al. 2007).
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