[Reposted today from earlier this year in support of the 2 May release of the intentionally funny documentary, Climate Hustle (across the US and a few Canadian locations) because host Marc Morano knows that polar bear numbers have not declined as people have been led to believe, see the trailer below]
Grim predictions of the imminent demise of polar bears – their “harsh prophetic reality” as it’s been called – have been touted since at least 2001. But such depressing prophesies have so widely missed the mark they can now be said to have failed.
While polar bears may be negatively affected by declines in sea ice sometime in the future, so far there is no convincing evidence that any unnatural harm has come to them. Indeed, global population size (described by officials as a “tentative guess“) appears to have grown slightly over this time, as the maximum estimated number was 28,370 in 1993 (Wiig and colleagues 1995; range 21,470-28,370) but rose to 31,000 in 2015 (Wiig and colleagues 2015, pdf here of 2015 IUCN Red List assessment; range 20,000-31,000).
Here are the failed predictions (in no particular order, references at the end):
Posted in Advocacy, Conservation Status, Population
Tagged Amstrup, Climate Hustle, declining population, Derocher, facts, failed prophesies, polar bear, population size, predictions, Red list, sea ice, Stirling
The air is thick with desperation on the polar bear front:
“[Andrew] Derocher said the polar bear population in the Beaufort Sea has fallen more than 50 per cent in the past 10 years.
“So it is a concern that this is probably one of the factors associated with the population decline,” he said.
As the CBC report in which this quote appears states immediately afterwards, there is no evidence for such a thing in the paper under discussion:
“The study found no direct evidence of that – all polar bears appeared to survive the swims recorded in the study.”
There is no truth to Derocher’s first statement either. Desperation – you don’t have to be a scientist to sense it. And the media wonder why people don’t trust them…
Posted in Uncategorized
Tagged Beaufort Sea, Derocher, desperation, Earth Day, facts, hype, Michaels, polar bear, population crash, sea ice, swimming
You may have seen the headlines in Canadian news outlets over the last 2 days.
“Polar bears swimming farther as sea ice recedes, study shows”
“Melting sea ice forces polar bears to swim longer, farther: study” [“Bear biologist Andrew Derocher says the forced swims are particularly hard on mothers with young cubs”]
“Polar bears swimming longer, farther because of melting sea ice, study finds”
Oddly, none of the above news reports said where the paper was published or mentioned the name of the lead author – only University of Alberta co-author Andrew Derocher was interviewed (see the only press release I could find here, issued by the San Diego Zoo where the lead author is now employed).[update: CBC ran another story a day later that corrected these omissions]
But what did the study actually say?
Significantly, no bears died while swimming during the two lowest sea ice extent summers since 1979 and no evidence was presented that swims were “particularly hard on mothers with young cubs.” The quotes from the paper below sum it up for Beaufort Sea (BS) bears (the inclusion of Hudson Bay (HB) bears in this study seems gratuitous and potentially misleading, since only a few swam anyway – only 15 out of 59):
“….91% (91/100) of the swims in the BS occurred before the annual September minimum sea ice extent had been reached. …In the BS, 81% (29/36) of swims started and ended in pack ice…”
So, despite what may be implied during media moments, Beaufort Sea polar bears were not frantically trying to reach the sea ice from land so that they could attempt to keep feeding over the summer – most of their swimming was done during breakup in July and August from one bit of pack ice to another and they showed no evidence of harm from doing so. Map from the study and more quotes below.
Posted in Life History, Sea ice habitat
Tagged Beaufort, Derocher, forced swims, Hudson Bay, mothers with young cubs, Pilfold, polar bear, receding sea ice, sea ice, summer, swim longer, swimming, swimming further
According to sea ice experts, winter sea ice habitat for polar bears is not expected to decline at all by 2050 and the critical spring sea ice that polar bears need for gorging on young seals and for mating is not predicted to change much (Durner et al. 2007, 2009), which is why computer modelled predictions about the dire future for polar bears only assessed the potential future effects of declining summer sea ice (e.g. Amstrup et al. 2007; Stirling and Derocher 2012). Note spring is April-June.
See if that fact is clear in the interview responses by out-spoken polar bear biologists that has just been published in the polar bear portion (“Beyond the polar bear”) of this year’s University of Alberta magazine spring climate change feature. If you can get past the “canaries in the coal mine” opener…
Posted in Advocacy, Sea ice habitat
Tagged advocacy, Derocher, facts, interview, polar bear, predictions, sea ice, spring sea ice, starving polar bears, Stirling, summer sea ice
What presents a bigger risk to current polar bear populations: natural hazards that have already proven deadly or potential, yet-to-be-realized threats prophesied to occur due to human activities? That’s a perfect question for International Polar Bear Day.
Dag Vongraven, chair of the IUCN Polar Bear Specialist Group, remarked last year that “until 2001, everything was fine.”
Polar bear researchers thus assume that 2001 was the year climate change became the new over-hunting – but is it true? What are the relative harms presented by proven natural causes, potential human-caused threats, and predicted threats due to sea ice declines blamed on global warming? Considered objectively, is climate change really the single biggest threat to polar bear health and survival right now?
Posted in Advocacy, Conservation Status, Population, Summary
Tagged climate change, Derocher, endangered, extinction, facts, forecast, global warming, hazards, International Polar Bear Day, IUCN, natural causes, natural variability, over-hunting, poaching, polar bear, prediction, sea ice, snow, Stirling, threatened, threats, Vongraven
Western Hudson Bay bear, Wakusp National Park, August 2011.
In the just-published version of their Western Hudson Bay (WHB) population survey conducted in 2011, Nick Lunn and colleagues highlighted in the abstract:
“Our analysis suggested a long-term decline in the number of bears from 1,185 (993-1411) in 1987 to 806 (653-984) in 2011…”
But they didn’t mention that the 806 estimate for 2011 was based on only a portion of the WHB region (Fig. 1) and has not been accepted by their peers as a valid estimate of the population size. They also failed to mention that the decline occurred due to thick spring ice and/or unsuitable snow conditions for ringed seals between 1989 and 1992 (Fig. 2), which resulted in reduced availability of polar bear prey (as I discussed in detail in Crockford 2015).
They know the “long-term” population decline is what the media will grab onto and run with – rather than the next sentence, which says “In the last 10 years of the study, the number of bears appeared stable due to temporary stability in sea ice conditions.”
In other words, their study shows there has been no decline in the population since 2004, which had been predicted to occur (see previous post, Prediction #1), and there has been no trend in either breakup or freeze-up dates between 2001 and 2010 (or since). See previous post on the government report on which this paper is based here.
The bottom line is this: no one is buying this population estimate of 806 bears for the Western Hudson Bay population – both the IUCN Polar Bear Specialist Group and Environment Canada are using Seth Stapleton and colleagues (2014) estimate from their aerial survey done the same year and that official population size number is 1030 bears. Continue reading
Posted in Advocacy, Population
Tagged declining, Derocher, ecl, facts, fewer bears, ice thickness, Lunn, polar bear, ringed seals, snow depth, stable, western hudson bay