Arctic sea ice has been growing steadily since the minimum extent was reached a month ago, with shorefast ice now developing along the Russian and Alaskan coastlines as ice cover expands in the Central Canadian Arctic. So while it’s true that the main pack of Arctic ice is far from the Russian shoreline, rapidly developing shorefast ice will allow bears to begin hunting seals long before ice in the central Arctic Basin reaches the Siberian shore, as they do in Western and Southern Hudson Bay every fall.
And speaking of Western Hudson Bay, it’s a very slow season around Churchill for problem polar bears (photo below) – the quietest mid-October for the Polar Bear Alert Program in the last five years and perhaps the quietest in decades (which I could say for sure if I had the records but I do not).
Posted in Life History, Polar bear attacks, Sea ice habitat
Tagged Barents Sea, Beaufort Sea, Churchill, Hudson Bay, pack ice, polar bear, polar bear alert, problem bears, sea ice, shorefast ice, thickness
It’s very open drift ice (1-4/10th concentration) but still: Bear Island (Bjørnøya) in the southern Barents Sea was still surrounded by pack ice at 15 May 2020. As far as I can tell from the Norwegian Ice Service archived ice charts, this hasn’t happened since 2003.
And last week, the island was surrounded by heavy drift ice, which hadn’t happened on 8 May since 1977.
A recent paper that attempted to correlate pollution levels and body condition in Barents Sea polar bears reports it found body condition of female bears had increased between 2004 and 2017 despite a pronounced decline in summer and winter sea ice extent.
“Unexpectedly, body condition of female polar bears from the Barents Sea has increased after 2005, although sea ice has retreated by ∼50% since the late 1990s in the area, and the length of the ice-free season has increased by over 20 weeks between 1979 and 2013. These changes are also accompanied by winter sea ice retreat that is especially pronounced in the Barents Sea compared to other Arctic areas” [Lippold et al. 2019:988]
Posted in academic freedom, Conservation Status, Life History, Population, Sea ice habitat
Tagged Barents Sea, body condition, denier, deplatformed, ice-free season, polar bear, sea ice, summer, Svalbard, threatened, vulnerable
For the second time this month, sea ice around Svalbard Norway was the 6th or 7th highest since records began in the late 1960s. Pack ice at the end of April still surrounds Bear Island (Bjørnøya) at the southern end of the archipelago, which is a rare occurrence at this date. These conditions document a recurrent pattern of high ice extent and especially extreme ice thickness in the Barents Sea since last summer.
Posted in Conservation Status, Population, Sea ice habitat
Tagged Barents Sea, Bear Island, icebergs, icebreaker, Novaya Zemlya, polar bear, Polarstern, sea ice, Svalbard, thick ice
From 3-7 April this year, sea ice around Svalbard Norway has been the highest since 1988, but only 6th or 7th highest since records began in the 1970s. Pack ice is year surrounds Bear Island (Bjørnøya) at the southern end of the archipelago for the first time since 2009 at this date, and continues the pattern of high extent and thickness of ice in the Barents Sea since last summer.
Sea ice around Svalbard, Norway at the end of February 2020 is way above average, as the graph below shows – with more polar bear habitat now than there has been in two decades.
Some comparison charts below show that the graph above includes some very high ice years in the 1980s (reaching that dotted line above the mean) for which only global charts are available.
However, contrary to suggestions that more Svalbard ice is better for polar bears, there is no evidence that low extent of sea ice habitat in winter or summer over the last two decades harmed polar bear health, reproductive performance, or abundance. In fact, polar bear numbers in 2015 were 42% higher than they were in 2004 (although not a significant increase, statistically speaking) and most bears were found to be in excellent condition.
This suggests a return to more extensive ice to the Svalbard region in winter will have little impact on the health of the entire Barents Sea subpopulation, although it might change where pregnant females are able to make their maternity dens if ice forms early enough in the fall. In other words, the population should continue to grow as it has been doing since the bears were protected by international treaty in 1973.
UPDATE 3 March 2020: According to 28 February tweet by the Norwegian Ice Service, which I just saw today, “the last time there was this much sea ice around Svalbard on this day of the year [28 February] was 2004“. Somehow, I missed 2004 when I was looking through the archive, so I have modified the text below accordingly; see the 2004 chart below and here.
Posted in Life History, Population, Sea ice habitat
Tagged Barents Sea, body condition, cub survival, denning, facts, Franz Josef Land, polar bear, science, sea ice, Svalbard
Arctic sea ice at the middle of winter (January-March) is a measure of what’s to come because winter ice is the set-up for early spring, the time when polar bears do most of their feeding on young seals.
[Mid-winter photos of polar bears are hard to come by, partly because the Arctic is still dark for most hours of the day, it’s still bitterly cold, and scientists don’t venture out to do work on polar bears until the end of March at the earliest]
At 12 February this year, the ice was similar in overall extent to 2013 but higher than 2006.
Word that Russia is planning to generate a count of polar bears along its entire Arctic coast within the next few years is good news indeed, as it will resolve a long-standing gap in population estimates that have not been dealt with at all well by the polar bear community. Whether North American and European academics will accept the results of the aerial surveys is another matter entirely, especially if the numbers are higher than they like, which is what happened with the first Russian Kara Sea count in 2013.
Up first will be the Chukchi and East Siberian Seas in 2021, the Laptev and Kara Seas, in 2022, and the eastern Barents Sea around Franz Josef Land in 2023.
Posted in Population
Tagged Barents Sea, Chuckhi Sea, counts, Franz Josef Land, global estimate, IUCN Red List, Kara Sea, Laptev Sea, PBSG, polar bear, population size, Russian
Most polar bears that spend the spring feeding in the peripheral seas of the Arctic Basin (such as the Beaufort, Chukchi, Kara, and Barents Seas) remain on the persistent pack ice of the central Arctic during the summer and this August, that refugium is still larger than Greenland. Most of these bears do not use this July-September Arctic Basin ice as a hunting platform unless they are very lucky: the few seals available are hard to catch. For the most part, polar bears fast or eat very little during the summer whether they are on land or on ice (see references in this post).
Since early June, sea ice experts have been wringing their hands over the melting of Arctic sea ice and offering breathless speculation that this year’s September minimum could be – gasp! – as low as or less than 2012 or even less. But now, as the graph of ice cover at 28 August shows below, that outcome is looking not just unlikely but virtually impossible (the blue line is 2019 extent, red dashed line is 2012, and the brown line is 2016):
As expected, the failure of the ice to remain on track to set a new record September low due to global warming is shrugged off with a reminder that summer ice extent “is sensitive to changes in daily weather conditions.”