There is still below average ice extent in the Barents Sea but there is no data whatsoever to indicate that this situation poses a problem for polar bears, given that as far as researchers know, polar bears eat little or nothing during the winter. That’s why the bears are at their leanest at the end of winter and why seal pups born in early spring are such a critical food source.
Note on map below (from WUWT Sea Ice Page, marked; original here) that polar bears are not found in three areas that are included in the total Arctic ice extent figures: below-average or above-average ice in the Sea of Okhotsk, Baltic Sea, and Gulf of St. Lawrence have no impact on polar bear health and survival.
Additional ice maps below. Continue reading
Posted in Life History, Sea ice habitat
Tagged Baltic, Barents Sea, Derocher, facts, fast, Gulf of St. Lawrence, polar bear, risk, sea ice, Sea of Okhotsk, t, threatened, winter
Using sea ice maps issued by the National Sea Ice Data Center (NSIDC), it’s interesting to compare these two years with respect to polar bear health and survival (keeping in mind that no polar bears live in what I like to call the armpits of the Arctic – the Sea of Okhotsk, the Baltic Sea or in the Gulf of St. Lawrence)1:
22 January 2016
Posted in Conservation Status, Sea ice habitat
Tagged Arctic, Baltic Sea, Barents Sea, darkness, Derocher, facts, feeding, Gulf of St. Lawrence, habitat, NSIDC, polar bear, sea ice extent, Sea of Okhotsk, spring, starving, survival, Svalbard, winter
Here are some facts to counter the misinformation and fearmongering being spread via twitter by a polar bear biologist who is getting carried away with his conservation activism.
Following up on my last post, I note that Arctic regions with sea ice but not polar bears were about 0.32 mkm2 below last year’s March average extent – which means the total ice decline from 2014 (0.4 mkm2) represents only a slight decline in polar bear habitat, most of which is in the Barents Sea (and due primarily to the state of the AMO, not global warming).
Sea ice extent for the Sea of Okhotsk and Baltic Sea combined (both areas without polar bears)1 were about 0.6 mkm2 below average this year for March. Average extent for March (according to NSIDC) is 15.5 mkm2, which means this year’s extent (14.4 mkm2) was 1.1 mkm2 below average, of which less than half (0.5 mkm2) was “lost” polar bear habitat.
IUCN Polar Bear Specialist Group biologist Andrew Derocher has been saying this is a “huge loss for polar bears” (see below): rational analysis of the facts show it is not. Continue reading
Posted in Advocacy, Sea ice habitat
Tagged activism, Baltic Sea, Barents Sea, Derocher, fearmongering, loss, maximum extent, misinformation, NSIDC, polar bear, record low, sea ice, Sea of Okhotsk, spring, spring ice
Only half or less of the estimated 2.6% loss per decade of March sea ice extent since 1979 (Fig. 1, below) represents a decline in polar habitat. That’s because several regions with sea ice that are not home to polar bears, like the Sea of Okhotsk, are included in Arctic sea ice totals.
Figure 1. Average monthly Arctic sea ice extent for March 1979-2015 (which includes ice in the Sea of Okhotsk, the Sea of Japan, and the Baltic, where polar bears do not live), shows a decline of 2.6% per decade. NSIDC, March summary 2015.
Both the Sea of Okhotsk and northern Sea of Japan (Fig. 2) have sea ice in winter (which is included in total Arctic sea ice records) but they are not truly “Arctic” – neither is connected to the Arctic by continuous ice, even when the ice is at its maximum extent (nor is the Baltic Sea — in contrast to Hudson Bay and the east coast of North America, which are connected to the Arctic by continuous ice).
Figure 2. Location of the Sea of Okhotsk and Sea of Japan. Insert ice map for March 1979 from NSIDC shows it’s position relative to the Arctic proper.
That lack of connection to Arctic pack ice is probably the main reason that polar bears never colonized the Sea of Okhotsk, even though western Arctic seal species (ringed, bearded, spotted, and ribbon) and Arctic whales (bowhead and beluga) live there. Polar bears don’t currently live in the Sea of Okhotsk and all evidence suggests they never have.
Sea ice maps show that about half of the total ice extent difference between March 1979 and March 2015 was due to a relatively large decline in sea ice cover for Sea of Okhotsk and northern Sea of Japan — regions without polar bears. Surely no reputable scientist or journalist would suggest that the “record low” maximum ice extent for 2015 has any relevance for polar bear health and survival? [or for Northwest Passage travel, for that matter] Sadly, they would.
Posted in Conservation Status, Sea ice habitat
Tagged Arctic, declining sea ice, Derocher, habitat, lost ice, lowest maximum extent, March, misinformation, NSIDC, polar bear, record low, sea ice, sea ice extent, sea ice maximum, Sea of Okhotsk, spring, variation
All Arctic sea ice habitats that are currently suitable for polar bears have polar bears living in them 1 – even the southern-most regions of Hudson Bay that are well below the Arctic Circle (see previous post on polar bear numbers here).
Have a look at the maps below and see how well the current maximum extent of sea ice correlates with the present range of polar bears around the Arctic.
Fig. 1. Sea ice extent at April 25, 2012, from NSIDC (the winter maximum). Note that although there is sea ice in the Sea of Okhotsk (top right of the map), polar bears do not currently live there nor is there any evidence they ever did1.
Compare to the polar bear’s official range below.
Fig. 2. The global range of the polar bear, showing the 19 regional subpopulations. Map from Polar Bear Specialist Group (PBSG), with a few extra labels added.