Tag Archives: polar bears

September sea ice ballyhoo and why it doesn’t matter to polar bears

The end of September sea ice summary from the US National Snow and Ice Data Center (NSIDC) finally became available late last week (October 3, “A better year for the cryosphere”).

The summary figure NSIDC provides are the average ice extent for the month (not the maximum achieved at the end of the month), which are compared to previous years.

[There has been considerable ice growth since the end of September (updated daily here].

Here is why the September extent doesn’t matter to polar bears: it is the extent in June that is important to polar bear survival. June is the end of the critical spring feeding period for polar bears (see previous post here) – healthy bears eat more seals over a shorter period of time from March to June than any other time of year. After the end of June, most bears have enough fat to survive a fast of 4 months or more.

In contrast to September – when many bears are taking a time-out on shore – ice extent for June over the last 30 years or so provided an extensive hunting platform for polar bears throughout the Arctic. To show you how extensive, I’ve constructed a composite of ice maps from selected years (Fig.1, below).

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Tracking polar bears in the Beaufort Sea: September map

Here is the follow-up to my post on the July track map for polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice. See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here).

The track map for September was posted on the USGS website on October 17 (delayed due to the US government shutdown) and is copied here below (Figure 1). The ice rebounded during the second half of the month (after the annual minimum was reached on September 13). The ten bears from July were down to eight – their collars might have stopped working or fallen off (most likely), they might have left the area entirely (also possible) or they might have died (the researchers don’t say which).

Figure 1. “Movements of 8 satellite-tagged polar bears for the month of September, 2013. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 8 of these bears have satellite collar transmitters [i.e., all are females]. Polar bear satellite telemetry data are shown with Ice Analysis charts from 26 August, 2013. Ice Analysis charts are made available by the National Ice Center. The land cover is made available by Natural Earth. Click on the above image to enlarge.” [Note that the dots with the polar bear icons are the end points (end September), while the other end of the string is their position in early September, indicating that the ice is now moving towards the shore. The pink dot present in August is almost entirely obscured by the purple dot, on shore in Alaska and the light brown dot is ashore on Banks Island, centre right of the map; two of the bears present in July (see Fig. 2 below) are no longer being tracked - their collars might have stopped working or fallen off (most likely), they might have left the area entirely (also possible) or they might have died. The researchers don’t say.] Click to enlarge

Figure 1. Original caption: “Movements of 8 satellite-tagged polar bears for the month of September, 2013. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 8 of these bears have satellite collar transmitters [i.e., all are females]. Polar bear satellite telemetry data are shown with Ice Analysis charts from 26 August, 2013. Ice Analysis charts are made available by the National Ice Center. The land cover is made available by Natural Earth. Click on the above image to enlarge.” [Note that the dots with the polar bear icons are the end points (end September), while the other end of the string is their position in early September, indicating that the ice is now moving towards the shore. The pink dot present in August is almost entirely obscured by the purple dot, which is overlapping the yellow dot on shore in Alaska; also, the light brown dot is on Banks Island, far right.]

It appears that of the eight polar bears still being followed by USGS researchers in September, four are on shore and four are still on the ice. Only time will tell if the four females on shore are pregnant and preparing maternity dens for the winter, but this seems the likely reason they are not on the ice with the others.

One very interesting point worth noting:
the one bear (light brown) captured onshore in the Southern Beaufort subpopulation region in the spring of 2013, has moved into the Northern Beaufort subpopulation region, on Banks Island (see map here), and may be denning there. This inter-subpopulation movement is relatively uncommon.

The map for July 2013 is below, for comparison: Continue reading

Beluga whales frolic in the High Arctic

Belugas at arcticwatch_with addressIt’s Thanksgiving weekend here in Canada. As a special treat, I thought I’d point you in the direction of a delightful bit of video footage of beluga whales.

If you haven’t seen this Arctic Watch Beluga Foundation clip already, it’s worth a few minutes. It’s footage of belugas and their calves frolicking in the shallow water of Cunningham Inlet, on Somerset Island, Nunavut (within the Lancaster Sound polar bear subpopulation, which is north of the Gulf of Boothia subpopulation region that I discussed previously here and here).

While I previously surmised that Gulf of Boothia polar bears might hunt beluga from remnant ice during the summer in years when the ice doesn’t totally melt (like they do in Hudson Bay, see belugas as food for hungry polar bears), it appears they also successfully hunt beluga in shallow waters like those found in Cunningham Inlet. But there is no hunting footage in this post.

Link and further info below, including a map and references on beluga, and polar bear predation on beluga in this region.

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Kaktovik polar bears could be back on the ice this weekend

This is a quick follow up on my last post (here) on Kaktovik polar bears of the Southern Beaufort Sea subpopulation.

Kaktovik is the bright pink dot on the ice map below (October 3, 2013: click to enlarge), from the Canadian Ice Service – if the ice doesn’t get to the polar bears waiting on shore this weekend, it will be within swimming distance.

Note that this map doesn’t show the shorefast ice that is already forming along the beaches, bridging the gap between land and the offshore ice.

Shorefast ice provides the fall’s first ice platform for polar bears to hunt seals. It doesn’t need to be extensive for the bears to get out there — researchers working in Western Hudson Bay found that an ice concentration of only 10% marked the point when polar bears left the shore.

Kaktovik on CIS chart Oct 3 2013

Polar bears at Kaktovik, Alaska not stranded due to retreating ice

“I’ve lived here all my life and there are more bears every year. I read stories about polar bears being on the brink of extinction because of global warming, look out of my window and start to laugh.” Tori Sims, Kaktovik (Mail on Sunday, Sept. 28, 2013).

As you can see, Kaktovik is in the news again. This tiny community sits on the edge of the Beaufort Sea, on Barter Island on the North Slope of Alaska (Fig. 1). It lies within the Southern Beaufort polar bear subpopulation, which has been classified as “declining” by the IUCN Polar Bear Specialist Group (Obbard et al. 2010).

The determination of “declining” was based on a small dip in population numbers between 2001 and 2006 (not statistically significant), plus a decline in body size and condition, and smaller litter sizes documented between 1986 and 2006 (Rode et al. 2010). A new population survey is underway.

Figure 1. Kaktovik, Alaska, from Google maps.

Figure 1. Kaktovik, Alaska, from Google maps. Click to enlarge.

There have been suggestions that bears become “stranded” along the Alaska coast near Kaktovik because of retreating sea ice, and that more bears present in this area in recent years are an indication that they are in trouble due to global warming.

I’ve compiled some quotes, maps, and links to stories, photos and videos about Kaktovik polar bears to show that this claim is false.

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What about the polar bears? Disconnect between predictions and observations

With all the talk this week about future climate – the global warming imagined by IPCC crystal ball models, that is – the focus for many is rightly on the gulf between predictions and observations that have taken place so far. This follows on reminders a few weeks ago of the many failed predictions that we would have seen an “ice-free Arctic” by now.

[by “ice-free” they mean “nearly ice-free,” or “when ice coverage is less than 1 million square kilometers, or about 386,000 square miles.”]

But what about the polar bears? Is there a similar disconnect between predictions and observations for polar bear survival? Yes, indeed.

Many Arctic biologists insist that polar bears are not just threatened by future global warming and a “melting ice cap.” They contend polar bears are already being harmed by declines in summer sea ice coverage, or will be shortly.

The problem is, the results of scientific studies show otherwise. Virtually all of the evidence generated by polar bear researchers shows that polar bears are not being harmed by declines in summer sea ice, and in some cases, they are doing very well indeed. In other words, they are not responding as expected.

A few weeks ago, I summarized these studies, which reveal that:

Less summer ice ≠ few bears (evidence from Davis Strait; S. Hudson Bay; Barents Sea; S. Beaufort; W. Hudson Bay).

Less summer ice ≠ “skinnier” bears (evidence from Chukchi Sea; S. Hudson Bay).

“Skinnier” bears ≠ fewer bears (evidence from S. Hudson Bay; S. Beaufort; Davis Strait).

Less summer ice ≠  lower cub survival (evidence from S. Hudson Bay; Chukchi Sea).

Less summer ice ≠ more cannibalism & hybridization

Have a look if you missed it (August 18, 2013, with pdf copies to download), “Polar bears have not been harmed by sea ice declines in summer – the evidence.”

[Update Sunday Sept 29 2013: these two stories (on the temperature pause and polar bears thriving (in which I get a mention), just out in the Mail on Sunday (UK)]

Mail on Sunday_Temp pause and polar bears_Sept 29 2013

What polar bear habitat could look like in another 5-6 weeks

According to the National Snow and Ice Data Center (NSIDC, Sept. 20 report), the annual sea ice minimum extent was reached on Sept. 13, 2013.

At 5.10 million square kilometers, this year’s low was a whopping 1.69 million square kilometers above the minimum extent for 2012 (which was the lowest since 1979) and well within two standard deviations of the 1979-2010 average. (Two standard deviations: “Measurements that fall far outside of the two standard deviation range or consistently fall outside that range suggest that something unusual is occurring that can’t be explained by normal processes”).

The minimum extent for 2013 is virtually indistinguishable from the minimum for 2009, which was 5.13 million square kilometers. The ice was distributed a bit differently in 2009 – more in the east and less in the west — than it was this year (see Fig. 1 below).

Figure 1. Using the JAXA “Sea ice monitor” feature, I plotted the date the 2013 minimum was reached (September 13, 5.10 million square kilometers, white) with an overlay (purple) for the same date back in 2009 (September 13, 2009, 5.13 million square kilometers), when that year’s minimum was reached (according to the NSIDC report). Areas of overlap are pink.

Figure 1. I used JAXA to plot the date the 2013 minimum was reached (September 13, 5.10 million square kilometers, white) with an overlay (purple) for the same date back in 2009 (September 13, 2009, 5.13 million square kilometers), when that year’s minimum was reached. Areas of overlap are pink.

You’ll know from previous discussions here that the annual minimum reached in late summer has little impact on polar bear health and survival (see excellent summary of the evidence for that here). What matters most to polar bears is the presence of ample ice in spring and early summer (March-June), which is their critical feeding period.

But after the fast that many polar bears endure over the height of the summer, they are eager to get back onto the ice and resume hunting. When in the fall does that become possible?

I wondered what the similarity in extent for 2013 and 2009 might tell us about polar bear habitat development over the next month or so.

In other words, what might polar bears this year expect in the way of sea ice development by say, the end of October? When might they be able to start hunting?

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How and why great news about Chukchi polar bears has been suppressed

A new peer-reviewed report (Rode et al. 2014 [in print] 2013, accepted), released last month (announced here), documents the fact that polar bears in the Chukchi Sea are doing better than virtually any other population studied, despite significant losses in summer sea ice over the last two decades – even though the Polar Bear Specialist Group (PBSG) said this population was declining (Obbard et al. 2010).

Rode and Regehr 2010_Chukchi_report2010_Fig1_triplets_labelled

Rather than this good news being shouted far and wide, what we’ve seen so far is a mere whisper. The strategy for suppressing the information appears to have several parts: make it hard to find; don’t actively publicize it; down-play the spectacularly good nature of the news; minimize how wrong they were; keep the focus on the future.

Something similar happened with the newly-published paper on Davis Strait bears (Peacock et al. 2013, discussed here and here) but the news there wasn’t quite so shockingly different from expected. The suppression of good news stands in marked contrast to anything with a hint of bad news, which gets reported around the world — for example, Andrew Derocher and colleagues and their prepare now to save polar bears” policy paper in February, 2013.

US Fish & Wildlife biologist Eric Regehr, co-investigator of the Chukchi study and co-author of the newly-published report, wrote an announcement about the paper. It wasn’t a real press release, since it was not actually sent to media outlets. It was a statement, with a brief summary of the paper, posted on a regional US Fish & Wildlife website, with no mention of lead author Karyn Rode. Not surprisingly, lack of active promotion = no media coverage.

The posted announcement also down-played how well the Chukchi bears are doing. In fact, the news documented in the paper is much better than any of them let on: Chukchi polar bears are doing better than virtually all other populations studied.

But Regehr also had to do some damage control to counter the evidence this paper contains of how wrong they had all been — not only about the Chukchi population today but about their predictions for polar bears in the future.

After all, the computer models used to predict a dire future for polar bears combined the Chukchi Sea with the Southern Beaufort, as having similar ice habitats (“ice ecoregions”). The published paper and Regehr’s statement now say these two regions are very different and that polar bear response to loss of sea ice is “complex” rather than a simple matter of less summer ice = harm to polar bears. Regehr goes on to say that polar bear scientists expected this would happen. I call total BS on this one, which I explain in full later (with a map).

Finally, Regehr’s statement emphasizes that good news for 1 subpopulation out of 19 today should not be celebrated because the overall future for polar bears — prophesied by computerized crystal balls — is bleak. Focus on the future, they say. Did they forget that for years they’ve been telling us that polar bears are already being harmed and that this foreshadows what’s to come? Now we have the results of yet another peer-reviewed study showing bears not being harmed by declines in summer ice (see the full list here).

So, in the end, all of this double-talk and contradiction is not just about suppressing this particular paper. There’s much more at stake.

The Rode et al. Chukchi paper is strong evidence that their predictions of a grim future for polar bears – based on theoretical responses to summer sea ice declines that should already be apparent – have been refuted by their own studies. It’s no wonder they want to keep the media away from this story.

Details below.  [Update September 11, 2013: another news outlet picks up the story, see Point 2 below]

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Biologists spreading misinformation: hybridization with grizzlies not due to polar bears moving inland

A paper published last week in the journal Science, written by a team of biologists and atmospheric scientists, expounds on a possible dire future for a range of Arctic animals. It’s called, “Ecological consequences of sea-ice decline” and surprisingly, polar bears are discussed only briefly.

However, with the inclusion of one short sentence, the paper manages to perpetuate misinformation on grizzly/polar bear hybridization that first appeared in a commentary essay three years ago in Nature  (Kelly et al. 2010)1. The Post et al. 2013 missive contains this astonishing statement (repeated by a Canadian Press news report):

Hybridization between polar bears and grizzly bears may be the result of increasing inland presence of polar bears as a result of a prolonged ice-free season.

Lead author of the paper, Professor of Biology Eric Post, is quoted extensively in the press release issued by his employer (Penn State University, pdf here). In it, Post re-states the above sentence in simpler terms, removing any doubt of its intended interpretation:

“… polar and grizzly bears already have been observed to have hybridized because polar bears now are spending more time on land, where they have contact with grizzlies.

Both statements are patently false. All recent hybridization events documented (2006-2013) occurred because a few male grizzlies traveled over the sea ice into polar bear territory and found themselves a polar bear female to impregnate (see news items here and here, Fig. 1 below). These events did not occur on land during the ice-free season (which is late summer/early fall), but on the sea ice in spring (March-May).

Grizzlies have been documented wandering over the sea ice of the western Arctic since at least 1885 (Doupe et al. 2007; Fig. 2, below) and the presence in this region of hybrid grizzly/polar bear offspring is not an indicator of declining summer sea ice, whether due to global warming or natural causes, or some combination thereof.

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Sea ice maximum reached March 15: what it means for polar bears

On Monday, March 25, the National Snow and Ice Data Center (NSIDC) announced that March 15 2013 was likely the maximum extent reached this winter. Note that just a few days ago, I discussed the relationship between maximum extent of sea ice and the global distribution of polar bears around the Arctic (see March 20th post here).

NSIDC says: “Arctic sea ice extent on March 15 was 15.13 million square kilometers (5.84 million square miles). The orange line shows the 1979 to 2000 median extent for that day. The black cross indicates the geographic North Pole.”

NSIDC says: “Arctic sea ice extent on March 15 was 15.13 million square kilometers (5.84 million square miles). The orange line shows the 1979 to 2000 median extent for that day. The black cross indicates the geographic North Pole.” Click to enlarge.

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