Tag Archives: thin ice

Shockingly thick first year ice between Barents Sea and the North Pole in mid-July

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.

Franz Josef Land polar bear 2019 no date_Photo by Michael Hambrey_sm

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.

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Summer habitat for most polar bears is either shoreline or sea ice in the Arctic Basin

At this time of year, sea ice extent numbers are meaningless for polar bears.  The extreme low September minimum of 2012 – when masses of polar bears didn’t die – showed rational people that this is true. Even the low 2007 summer extent, which hit earlier in the season than 2012, had little to no negative impact.

Greenland W coast_Female w cubs_2006_Mads Heide-Jorgensen_NOAA sm

In late summer, bears outside the Canadian Archipelago either retreat to shore or stay on the sea ice as it retreats north into the Arctic Basin (see image below, click to enlarge).  Most bears in the Archipelago have ice year round, so life doesn’t change much. This means that it does not matter to polar bears how much area the Arctic Basin ice covers in September – for their needs, 1.0 mkm2 would be plenty.

Sea ice and summer refuges for polar bears_17 Aug 2015

Still, Southern Hudson Bay polar bears had extended hunting opportunities in July this year (whether or not they hunted successfully) and for this date, Hudson Bay had more ice remaining than any year on record. Yes, more than even 1992 but only by a few percent. See charts and maps below.

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Polar bear behaviour gets the animal tragedy porn treatment – two new papers

Recently, several polar bear biologists have teamed up with photographers to get pictures of starving bears into the scientific literature – and picked up by the media, with mixed results.

doi:10.3402/polar.v34.26612
For the second time in five years, polar bear biologist Ian Stirling has teamed up with a photographer to give unwarranted scientific credence to an anecdotal account of polar bear behaviour. It included a picture of a pitifully thin animal  (classic animal tragedy porn) and was framed to increase alarm over predicted effects of global warming. It got little media attention.

His Norwegian colleagues Jon Aars and Magnus Andersen have just done the same with a bear caught eating a white-beaked dolphin (photo above) – but this time the media took the bait.

Update 13 June 2015 – Information added on white-beaked dolphin distribution, sea ice conditions in 2014 and a correction. See below.
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