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.”
In late June, one of the most powerful icebreakers in the world encountered such extraordinarily thick ice on-route to the North Pole (with a polar bear specialist and deep-pocketed, Attenborough-class tourists onboard) that it took a day and a half longer than expected to get there. A few weeks later, in mid-July, a Norwegian icebreaker also bound for the North Pole (with scientific researchers on board) was forced to turn back north of Svalbard when it unexpectedly encountered impenetrable pack ice.
A polar bear on hummocked sea ice in Franz Josef Land. Photo by Michael Hambrey, date not specified but estimated based on tour dates to be 22 or 23 June 2019.
Apparently, the ice charts the Norwegian captain consulted showed ‘first year ice‘ – ice that formed the previous fall, defined as less than 2 m thick (6.6 ft) – which is often much broken up by early summer. However, what he and his Russian colleague came up against was consolidated first year pack ice up to 3 m thick (about 10 ft). Such thick first year ice was not just unexpected but by definition, should have been impossible.
Ice charts for the last few years that estimate actual ice thickness (rather than age) show ice >2 m thick east and/or just north of Svalbard and around the North Poie is not unusual at this time of year. This suggests that the propensity of navigational charts to use ice ‘age’ (e.g. first year vs. multi-year) to describe ice conditions could explain the Norwegian captain getting caught off-guard by exceptionally thick first year ice. It also provides an explanation for why the polar bear specialist onboard the Russian icebreaker later failed to explain that first year ice of such shocking thickness was truly extraordinary, not just a bit thicker than usual.
Posted in Advocacy, Sea ice habitat
Tagged Barents Sea, extent, first year ice, Franz Josef Land, ice age, icebreaker, North Pole, polar bear, sea ice, Svalbard, thick ice, thin ice
Results from spring Norwegian fieldwork in the Svalbard region of the Barents Sea are in and they show that despite having to deal with the most extreme loss of summer sea ice in the Arctic, polar bears in this region continue to thrive.
Svalbard polar bear territory (managed by Norway) includes sea ice to the Russian boarder to the east as well as the area around the Svalbard archipelago: the map below is from Aars et al. 2017.
Observations were collected around Svalbard by a team lead by Jon Aars and Magnus Andersen of the Norwegian Polar Institute between March and May this year, and posted online 4 June 2019. Kudos to them for making their on-going observations and analysis available, in a timely manner for all to see.
Note that Svalbard is the western half of the ‘Barents Sea’ polar bear subpopulation: in recent years, most of the region’s polar bears have been living around Franz Josef Land in the eastern (Russian) sector where Norwegian researchers are not permitted to work.
Posted in Conservation Status, Population, Sea ice habitat
Tagged Barents Sea, condition, data, litter size, males, Norway, number of cubs, observations, polar bear, sea ice, Svalbard