This year’s baseless media frenzy over walrus survival and loss of summer sea ice blamed on human-caused global warming was initiated by a press release from US Fish and Wildlife last week (16 August 2017, pdf here: “Pacific walruses haul out near Point Lay earlier than in previous years“). Quote below, my bold:
In the first week of August, several hundred Pacific walruses were observed on a barrier island near the Native Village of Point Lay, a small, Iñupiaq community on the northwest coast of Alaska. This is the earliest date yet for the haulout to form…This year, sea ice has retreated beyond the continental shelf earlier than in previous years
But is this all true? In a word, no — and it didn’t take much research to uncover the truth.
UPDATE 24 August 2017: A few minutes after this post was published, I became aware that just yesterday, 20 conservation activist organizations, lead by the Center for Biological Diversity (who led the polar bear listing charge) issued a press release regarding a letter (pdf here) pressuring the US Fish and Wildlife Service to list Pacific walrus as threatened or endangered under the Endangered Species Act. Apparently, a decision must be made by the end of September on whether to actively list walrus or not. The text below has been amended to reflect this development.
Posted in Advocacy, Conservation Status, Summary, walrus
Tagged Alaska, Chukchi Sea, climate change, earliest, endangered, ESA, fact check, facts, global warming, haulout, hype, Point Lay, sea ice, summary, US Fish and Wildlife Service, video, walrus
There’s been no word as yet, either from tour operators or polar bear researchers, that Western Hudson Bay polar bears have come ashore for the summer/fall season. Andrew Derocher reported at the end of June that the bears tagged by his team were still on the ice and as I write this, has not yet reported them ashore.
That pattern is consistent with the presence of thick ice along the west coast of the Bay — from well north of Churchill to the south of Wapusk National Park — for the last few weeks. The weekly chart for 3 July 2017 below from the Canadian Ice Service shows that virtually all of the ice remaining is thick first year ice (>1.2m, dark green on this map):
By the 9 July, the extent of this patch of ice was somewhat reduced but still a very prominent feature over the Bay, suggesting that if adult seals are using this ice as a refuge while molting, some bears may still be attempting to hunt even though their success rate may not be very high:
Bottom line: As has been the pattern for more than a decade, 2017 will not go down in history as an especially early year for WHB polar bears coming off the ice for the summer/fall season but instead may be as late as last year, when lots of bears were reported off the ice by mid-July at Seal River (just north of Churchill), all in excellent condition.
It remains to be seen if the condition of bears will be as good this year as they were in 2016, given the late start to the season. But it does mean that the lack of trend in breakup dates since 2001 continues: breakup of the sea ice in WHB since 2001 has been about one week later than it was before 1998 (Castro de la Guardia 2017; Cherry et al. 2013; Lunn et al. 2016).
If some polar bear struggle to survive this year it will be due to the late freeze-up date last fall combined with challenging winter conditions over Hudson Bay, not because of an early breakup of the sea ice.
And while it is certainly true that the overall trend in time spent onshore by WHB polar bears since 1979 has increased by about three weeks, the lack of a continued trend since 2001 is not what was expected or predicted, especially given the marked decline in global sea ice levels that have made headlines since 2007 (Crockford 2017), and the predictions of how devastating such low levels of ice would be to polar bears in areas like Hudson Bay that have to deal with a total disappearance of sea ice in summer and early fall.
Posted in Life History, Sea ice habitat
Tagged breakup, Churchill, global warming, hunting, melting ice, polar bear, predictions, sea ice, Seal River, shore, western hudson bay
Heavy sea ice off Newfoundland and southern Labrador has been an issue for months: it brought record-breaking numbers of polar bear visitors onshore in early March and April and since then has hampered the efforts of fisherman to get out to sea.
Let’s look back in time at how the ice built up, from early January to today, using ice maps and charts I’ve downloaded from the Canadian Ice Service and news reports published over the last few months.
The tour is illuminating because it shows the development of the thick ice over time and shows how strong winds from a May storm combined with an extensive iceberg field contributed to the current situation.
Bottom line: I can only conclude that climate change researcher David Barber was grandstanding today when he told the media that global warming is to blame for Newfoundland’s record thick sea ice conditions this year. I suspect that because Barber’s expensive research expedition was scuttled, he simply had to find a way to garner media attention for his project — and the media obliged. Read to the end and decide for yourself.
Posted in Advocacy, Sea ice habitat
Tagged Arctic ice, Barber, climate change, global warming, icebergs, multiyear ice, Newfoundland, sea ice, Strait of Belle Isle, thick sea ice, trapped in ice
A new paper on the evolutionary history of bears (Bears breed across species borders: Kumar et al. 2017) has concluded that hybridization is common and natural among all species of ursids. And while some media outlets (e.g. DailyMail) have framed this as surprisingly convincing proof that experts were wrong to claim that climate change is the cause of recent polar bear X grizzly hybrids, definitive evidence against that interpretation has been available for years to anyone who bothered to look: see my recent “Five facts that challenge hybridization nonsense.”
This genetic evidence is just a cherry on top of the rest but will help get the paper the media attention the authors crave.
Polar bear X grizzly hybrids were known long before climate change and sea ice decline became an issue. See also previous posts here, here, and here. In fact, as I’ve pointed out, “most polar bear hybrids said to exist have not been confirmed by DNA testing” (including virtually all of the bears specialist Andrew Derocher claimed were hybrids, including the latest one from 2016 that prompted such gems as “Love in the time of climate change”).
A polar bear X grizzly hybrid, see Kumar et al. 2017. Photo by A. Derocher.
In my opinion, the most important conclusion of this paper is that occasional but widespread hybridization among bears is why it has been so hard to say with confidence when polar bears arose (which I addressed years ago, in my Polar bear evolution series: Part 1, Part 2, and Part 3). You cannot use traditional methods of pinpointing the timing of speciation events from genetic data if one or more of the species have hybridized (traded genes). See the long, fuzzy “divergence times” for bears in the image below from the Kumar paper.
From Kumar et al. 2017, Fig. 5: “The scale bar shows divergence times in million years and 95% confidence intervals for divergence times [speciation events] are shown as shadings.”
Posted in Evolution, Hybridization
Tagged bears, climate change, evolution, global warming, grolar bear, hybridization, media hype, pizzly, species, ursids