Tag Archives: Barents Sea

Polar bear habitat update early spring 2018

Spring in the Arctic is April-June (Pilfold et al. 2015). As late April is the peak of this critical spring feeding period for most polar bear populations, this is when sea ice conditions are also critical. This year, as has been true since 1979, that sea ice coverage is abundant across the Arctic for seals that are giving birth and mating at this time as well as for polar bears busy feeding on young seals and mating.

Polar_Bear_male on sea ice_Alaska Katovik Regehr photo_April 29, 2005_sm labeled

Below is a chart of sea ice at 25 April 2018, showing sea ice in all PBSG polar bear subpopulation regions:

masie_all_zoom_4km 2018 April 25

Some Arctic subregions below, in detail. Continue reading

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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Franz Josef Land is a sea ice refugium for most pregnant Barents Sea polar bears

Consensus polar bear expert Andrew Derocher has been busy over the last few weeks, expounding a story of doom regarding Svalbard area polar bears (e.g. here and here), ridiculing the suggestion that Franz Josef Land is viable alternate habitat for Barents Sea bears, especially pregnant females looking for a place to den and give birth. But the facts say otherwise.

Svalbard polar bear_Aars August 2015-NP058930_press release

Below are the long answers, with references and ice maps, to the questions Derocher asked in his 21 December 2017 tweet (above), a refreshing change from the ‘take my word for it, I’m the official expert’ answer one gets from him, along with derogatory slurs directed at those who don’t share his pessimism.

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Svalbard polar bear habitat higher than average – here’s what that looks like

Polar bear habitat around Svalbard in the Barents Sea is currently slightly above average for 23 June 2017: this short post records what that amount of ice looks like according to the Norwegian Ice Service (NIS).

Svalbard ice extent 2017 June 23_NIS from archive

Compare to 2015 at the same date, the year that the last polar bear count was conducted for the Svalbard region, when many cubs were seen and the bears were reported in excellent condition:

Svalbard ice extent 2015 June 23_NIS from archive

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IUCN PBSG insists the 2015 Barents Sea polar bear count was not an increase

Similar to the spin on the 2013 Baffin Bay/Kane Basin polar bear population survey, the IUCN Polar Bear Specialist Group now insists the latest count of the Barents Sea subpopulation is not evidence of an increase in numbers since 2004, as the leader of the study announced in 2015.

Svalbard polar bear_Aars August 2015-NP058930_press release

This is Part 2 of the big surprises in the latest version of the polar bear status table published by the IUCN Polar Bear Specialist Group (PBSG) on 30 March 2017. See last post here regarding the PBSG population size estimates that no longer concur with the 2015 Red List assessment, including the global total — even though PBSG members wrote the report (Wiig et al. 2015, and its Supplement).

Here I want to focus on the results of subpopulation surveys that were made public after the 2015 Red List assessment was published, particularly the Barents Sea estimate.

While the 2013 Baffin Bay and Kane Basin estimates (SWG 2016) have been added to the new PBSG table, any suggestion that these might indicate population increases are strong discounted. Similarly, contrary to initial reports by the principal investigators of the survey, the PBSG insist that the Barents Sea population has not actually increased since 2004, which you may or many not find convincing.

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Polar bear habitat message for the year end: 2016 Arctic ice extent same as 2010

According to NSIDC daily sea ice interactive graph,  there was ever so slightly more ice on 31 Dec 2016 than on that date in 2010. However, the corresponding ice maps show just how differently that ice was distributed.

sea-ice-at-31-dec-2016_vs-2010_nsidc-interactive

Recall that in 2010, there was no huge die-off of polar bears attributed to reduced amounts of sea ice in the fall (or to reduced ice in summer, for that matter) because there was no catastrophic die-off at all.

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Fall Arctic ice growth often differs regionally: 2016 compared to other years

Arctic sea ice is spreading out quickly from its central basin summer refuge – according to this NSIDC Masie ice chart, it has already grown more than 2 mkm2 beyond the annual minimum reached in early September. Ice is already pushing south into the eastern Beaufort and the archipelago of Franz Josef Land in the Barents Sea.

masie-sea-ice-2016-oct-20-cropped-and-marked_polarbearscience

Over the next couple of weeks, shorefast ice will start forming along the coasts of North America and Eurasia (see the first bits off Alaska in the 21 October CIS map below), which will eventually meet the expanding Arctic Basin pack to fill the Basin and Canadian Arctic Archipelago with ice – as it has done for eons.

sea-ice-extent-canada-2016-oct-21_cis

The evidence from the last decade or so suggests that by the end of October, most of the Arctic north of the 79th parallel (see map below) will be filled with ice – although the Chukchi Sea (north of the Bering Strait) may not fill until sometime in November:

79-th-parallel-north_wikipedia

Polar bears usually resume hunting as soon as sea ice conditions permit in the fall, since it’s their last chance to top up their fat reserves before the dark and cold of winter when hunting may become next to impossible.

I’ve copied ice charts from the Masie archives for some previous years at 31 October below.

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