Tag Archives: climate change

Abrupt summer sea ice decline has not affected polar bear numbers as predicted

Yes, Arctic sea ice has declined since satellite records began in 1979 but polar bears have adjusted well to this change, especially to the abrupt decline to low summer sea ice levels that have been the norm since 2007.

Global pb population size sea ice 2017 July PolarBearScience

Some polar bear subpopulations have indeed spent more time on land in summer than in previous decades but this had little negative impact on health or survival and while polar bear attacks on humans appear to have increased in recent years (Wilder et al. 2017), the reasons for this are not clear: reduced summer sea ice is almost certainly not the causal factor (see previous post here).

Ultimately, there is little reason to accept as plausible the computer models (e.g. Atwood et al. 2016; Regehr et al. 2016) that suggest polar bear numbers will decline by 30% or more within a few decades: even the IUCN Red List assessment (Wiig et al. 2015) determined the probability of that happening was only 70%.

Arctic sea ice has never been a stable living platform (Crockford 2015): it shifts from season to season, year to year, and millennia to millennia. Without the ability to adapt to changing conditions, Arctic species like polar bears and their prey species (seals, walrus, beluga, narwhal) would not have survived the unimaginably extreme changes in ice extent and thickness that have occurred over the last 30,000 years, let alone the extremes of sea ice they endured in the last 200,000 years or so.

Some biologists continue to hawk doomsday scenarios for polar bears due to summer sea ice loss but the truth is that their previous predictions based on sea ice declines failed so miserably (e.g. Amstrup et al. 2007) that it’s impossible to take the new ones seriously — especially since the basic assumptions that caused the first predictions to fail have not been corrected, as I’ve stated in print (Crockford 2017:27):

In summary, recent research has shown that most bears are capable of surviving a summer fast of five months or so as long as they have fed sufficiently from late winter through spring, which appears to have taken place since 2007 despite marked declines in summer sea ice extent.

The assumption that summer sea ice is critical feeding habitat for polar bears is not supported.

Recent research shows that changes in summer ice extent generally matter much less than assumed in predictive polar bear survival models of the early 2000s as well as in recent models devised to replace them (Amstrup et al. 2010; Atwood et al. 2016a; Regehr et al. 2015; Regeher et al. 2016; Wiig et al. 2015), while variations in spring ice conditions matter more.

As a consequence, the evidence to date suggests that even if an ‘ice-free’ summer occurs sometime in the future ­ defined as sea ice extent of 1 million km2 or less (Jahn et al. 2016) ­ it is unlikely to have a devastating impact on polar bears or their prey. [my bold]

The abrupt drop in summer sea ice that occurred in 2007 was not predicted by experts to occur until mid-century yet the predicted decimation of polar bears worldwide expected under those conditions (a loss of 2/3 of the global total, to only about 6660-8325 bears) not only did not happen, it did not come even close to happening (Crockford 2017; see also my recent books, Polar Bear Facts & Myths, and Polar Bears: Outstanding Survivors of Climate Change, sidebar).

Instead, the global population grew from about 22,550 bears in 2005 to about 28,500 bears in 2015. And while this might not be a statistically significant increase (due to the very wide margins of error for polar bear estimates), it is absolutely not a decline.

The present reality is that low summer sea ice cover since 2007 has not caused polar bear numbers to decline and therefore, polar bears are not a species in trouble. This suggests that even if the Arctic should become briefly ice-free in summer in the future, polar bears are likely to be only minimally affected and not become threatened with extinction. Polar bears are outstanding survivors of climate change: recent research and their evolutionary history confirm this to be true.

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Heavy ice off East Coast 2017 caused by winds, cold temperatures, and icebergs

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.

Newfoundland fishing boats stuck in ice_DFO_May 26 2017 CBC

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.

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New genetics paper is not about whether climate change causes polar bear hybrids

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”).

pizzly_andrewderocher_300dpi_2017 paper

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.

Kumar et al 2017 hybridization in bear evolution_fig 5

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.”

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Maclean’s blames global warming for polar bear visits to Newfoundland

Without a shred of evidence, Canada’s Maclean’s magazine claims recent polar bear sightings in Newfoundland and Labrador are due to global warming — and concludes that such incidents are bound to get worse.

Macleans 7 April 2017 polar bear headline with photo_sized

But since it’s likely that polar bear populations in Davis Strait are still increasing (as they were in 2007), Maclean’s might be correct in their prophesy that bear visitations are bound to get worse — just not for the reason they think.

Without any justification or even a quote from an expert, the author of this piece (Meagan Campbell)  blames man-made global warming for recent polar bear visits to Labrador and Newfoundland:

“Since bear sightings in the early winter have been linked to climate change, some parents are more concerned for their future grandchildren.” 

That’s just bad logic. Actually, the fact that global warming has not killed off polar bears as predicted means there are lots of bears to come ashore causing problems in late winter (while they wait for Arctic seal pups to be born, so they can eat them).
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Thriving numbers – & two great books – are ample reason to rejoice on Polar Bear Day

Ten years of summer sea ice levels expected to kill 2/3 of the world’s polar bears by 2050 instead saw polar bear numbers grow. And this year, there are also two fabulous books about polar bears and their outstanding success story to celebrate on International Polar Bear Day (Monday 27 February 2017).

os-and-fm-cover-drafts-14-dec-2016

One is suitable for kids (Polar Bear Facts & Myths) and another for adults and teens who want the details (Polar Bears: Outstanding Survivors of Climate Change) – see the right sidebar to buy on Amazon or my author website for details on all additional formats. A couple of excerpts from them are below.

So forget turning down your thermostat in a pointless gesture to “reduce your carbon emissions and help polar bears” — as Polar Bears International advocates for Polar Bear Day. Instead, treat yourself or a friend and order a book with a rational approach to species survival.

Speaking of species survival, think about the inconsistency in how some species are treated according to the US Endangered Species Act (ESA). Humpback whale numbers recovered after decades of protection; in 2016, after the state of Alaska filed a petition to delist, most populations were officially removed from the ESA list of ‘threatened’ species.

humpback-whale-and-calf-012016-noaa

Humpback whale and calf, NOAA image.

In contrast, by 2015, polar bear numbers had also recovered despite years of low sea ice loss not predicted until 2050, yet remain officially ‘threatened’ with extinction.

polar_bear_family_at_bone_pile-kaktovik-20-april-2016

Fat bear family at Kaktovik, Alaska (Southern Beaufort), April 2016. USGS photo.

US National Marine Fisheries Service defended the delisting of humpback whales against activists who insisted human-caused global warming threatened the species, but the US Fish and Wildlife Service defends flawed polar bear prophesies.

My books lay out the polar bear success story: in simple form for younger readers and in detail for others. See the excerpts below.

crockford-pb-outstanding-survivors-2017_end-of-pg-30

Polar bears have not been driven to the brink of extinction by global warming. In fact, they are thriving (see my final conclusions on pg. 30 of Polar Bears: Outstanding Survivors of Climate Change, above and pg. 32 of Polar Bear Facts & Myths below.

crockford-pb-facts-and-myths-2017-pg-32

If you’d like to support my efforts to bring this to everyone’s attention, please consider buying a copy or two of my books. If you’ve already done so, keep in mind that your local library might be glad to have copies donated. They also make great gifts.

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Fake news on polar bear survival predictions is political posturing

I call this fake news because it’s not news – media headlines around the world today (New York Times, Washington Post, DailyMail) are trumpeting the release of a final version of a draft report released with similar fanfare more than a year ago, announced today by the US Fish & Wildlife Service in the official US government publication, Federal Register.

biggest-threat-to-polar-bears-is-global-warming-nyt-headline_9-jan-2017

Without action on climate change, say goodbye to polar bears” is exactly the kind of sensationalized nonsense I address in my new detailed science book, Polar Bears: Outstanding Survivors of Climate Change (announced here, discussed here).
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Communicating polar bear science requires a rational approach

My most requested public lecture, Polar Bears: Outstanding Survivors of Climate Change, has been hugely popular with audiences in my Canadian home town of Victoria, British Columbia, and my newly-released book with the same title (based on that lecture) promises to be similarly successful. Here are some thoughts on both.

crockford_outstanding-survivors_lecture-vs-book-jan-2017

Recently (5 January 5, 2017), I gave another free lecture about polar bears to a local non-profit organization through my university’s Speakers Bureau. I’ve been doing this since 2009, although the shear volume of requests has been much higher this past year than previously. As before, my lecture was warmly received and audience members asked questions indicating they had been listening with an open mind. A colleague I spoke to expressed surprise at that outcome, given where I live.

Keep in mind that Victoria is home to litigation-prone IPCC climate scientist turned BC provincial Green Party politician Andrew Weaver (in whose riding I happen to reside) as well as one of the many targets of fake Nobel Laureate Michael Mann and his over-sensitive ego, veteran climate scientist Tim Ball (who defends the defamation lawsuit filed against him by Mann at trial in Vancouver, B.C. 20 February 2017,  an event which defender of free speech and fellow defendant against Mann’s litigious wrath, Mark Steyn,  has said he’ll be attending). And yes, in a sort of home-town science brawl, Weaver also sued Tim Ball, but that case has not yet gone to court. Victoria is also the constituency of our lone federal Green Party Member of Parliament, Elizabeth May. Canadian journalist Donna Laframboise once described Victoria as “one of the most left-leaning corners of the country.

So it is into this virtual lion’s den of anthropogenic global warming champions that I venture, several times a month, to enlighten adults, teachers, and students who have been left with the impression that there are only a few hundred starving polar bears left in the world.1

The secret to the kind of reception I receive – even in my town – is to present the relevant facts without emotional overtones and let audiences make up their own minds about what they think of the situation.

This latest lecture was not only well received but several audience members bought copies of my kid-friendly Polar Bear Facts and Myths that I had for sale (reviewed here by Kip Hansen).  One member came up afterwards to say he’d been dreading what he’d anticipated would be another polar-bears-are-doomed diatribe but was very pleased at my even-handed, scientific approach.

That’s why I decided to fashion my first fully referenced polar bear science book – and take it’s title – from my most successful public lecture. Audience responses over the years indicated to me that a simple summary would be an appealing approach. Questions from audience members over the years suggested which topics might need a more detailed explanation in the book. The lesson I learned from my lecturing experience was that my book needed a focused style, plenty of color images, and an affordable price.

Consider the table of contents for the new book, where each chapter covers only a few pages:

1. Polar bear & sea ice basics
2. Feasting/fasting life of polar bears
3. Evolution & climate change
4. Conservation & protection
5. Failure of the polar bear predictions
6. Biggest threat to polar bears
7. Summary
8. Conclusions

I expect I’ll get some negative fake reviews posted on Amazon for Polar Bears: Outstanding Survivors of Climate Change from the self-appointed moral-high-ground troll network (as they did for Polar Bear Facts and Myths). That’s to be expected for a topic like this. Honest criticism from readers might also be generated, of course, and that’s something all writers can expect, and should welcome.

That said, the best way to counter biased or unconstructive reviews is with honest, heartfelt reviews from readers who have actually read the book. If any of you that have ordered a copy of this book but would like to see a pdf review document in order to post an immediate review, use the contact me form at “Comments/Tips.”

Both Polar Bears: Outstanding Survivors of Climate Change and Polar Bear Facts and Myths are now available in paperback and various ebook formats, including epub and pdf. The little spin-off for preschoolers (Polar Bears Have Big Feet) – because why shouldn’t the little kids have a fear-mongering-free polar bear book with great pictures too? – is available in paperback only.

Footnote

  1. Without exception, every teacher of every school class I have spoken to in Victoria in the past year has been absolutely astonished to learn that the official global population estimate for polar bears is now 22,000-31,000, the highest estimate in 50 years. Virtually all expressed their appreciation for pointing out that simple fact. Hence, Polar Bear Facts and Myths is aimed at those misinformed children, while Polar Bears: Outstanding Survivors of Climate Change is aimed at their teachers, parents, and other influential relatives.