Tag Archives: arctic sea ice

Recent studies show Sept ice of 3-5 mkm2 did not kill polar bears off as predicted

The annual Arctic sea ice minimum for 2016 is imminent and the hand-wringing about polar bear survival has already begun. While this year is shaping up to be another very low sea ice minimum in the Arctic – not as low as 2012 but lower than as low as 2007 (previously the 2nd lowest since 1979) – contrary to predictions, several recent studies show that such low sea ice coverage in summer has had no (or very limited) negative effects on polar bear health and survival. In fact, for polar bears in some areas low summer sea ice has been quite beneficial (although these are not the populations that polar bear specialists predicted would do better).

polar_thin_ice Jessica Robertson_USGS

Since low summer extents of recent magnitude (3.0 – 5.0 mkm2) are clearly not any sort of threat to polar bears, it seems improbable that even an ice-free (≤ 1.0 mkm2) summer (e.g. Wang and Overland 2015) would be devastating to the species [don’t forget Cronin and Cronin 2016: they’ve survived such conditions before] – as long as conditions in spring allow for the necessary concentrated feeding on young seals.

sea-ice-mins_2007_2012_2015_polarbearscienceAbove: Top, minimum at 2012 (16 Sept, 3.41 mkm2, lowest since 1979); Center, 2007 (18 Sept, 4.17 mkm2); Bottom, 2015 (9 Sept, 4.50 mkm2), from NSIDC. Below: sea ice at 10 Sept 2016, 4.137 mkm2 – minimum not yet called).


Recall that in 2006, the IUCN Polar Bear Specialist Group based their conservation status of ‘vulnerable’ (likely to become threatened within the next 45 years due to reduced habitat) on the predictions of sea ice specialists (see 2008 update here).

Sea ice experts in 2005 predicted such low summer sea ice extents as polar bears have endured since 2007 (3.0 – 5.0 mkm2) would not happen until 2040-2070, at which time PBSG biologists said that >30% of the world’s bears would be gone.

Evidence to the contrary comes from polar bear specialists working in the Chukchi, Beaufort, and Barents Seas – and in Southern Hudson Bay – since 2007. Overall, the latest IUCN Red Book assessment (2015) put the global population size at 22,000-31,000 (or about 26,500).

All of this means that those polar bear experts were wrong: polar bears are more resilient to low summer sea ice conditions than they assumed.

UPDATE 2 January 2017: I’ve added some quotes from the original USGS reports that explicitly state their dire predictions for 2050 that differ from the predictions made by the IUCN Polar Bear Specialist Group.
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Barents Sea polar bears in excellent condition say Norwegian biologists

Conditions this year (2015) in the Barents Sea were excellent according to the polar bear researchers who work there (“Polar bears were as fat as pigs”).

Barents Sea bear 2015 August Cobbing_NPI
A new survey just completed for a population count showed the bears were are in excellent condition – except the injured ones, of course, which some news organizations are promoting as evidence of harm from global warming-induced sea ice changes because an activist photographer  – not scientists – said so.

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Melt season update – Bering Sea ice abundant & Davis Strait ice 2nd highest since 1971

Polar bear habitat in the eastern Bering Sea has expanded since the official spring “maximum extent” was called for late February, and Davis Strait sea ice is tied for 2nd highest since 1971 for this week. Both regions have healthy polar bear populations and spring conditions suggest this will continue into this year.

Rode and Regehr 2010_Chukchi_report2010_Fig1_triplets_labelled

Although the melt season is underway, as of yesterday (22 April, Julian day 112) overall Arctic sea ice extent (Fig. 1) was higher than it was on the same date in 2014, 2007, and 2004 (see also Fig. 2). Despite the record low extent in February (Fig. 3), that pessimists at Polar Bears International suggested was relevant to polar bear heath and survival, I showed that was misleading.

Figure 1. Sea ice extent at 22 April (Julian day 112) for 2015, at 13.976 mkm2, was well within 2 standard deviations and higher than 2007 (shown) as well as 2004 and 2014 (not shown – see it for yourself here).

Figure 1. Sea ice extent at 22 April (Julian day 112) for 2015, at 13.976 mkm2, was well within 2 standard deviations and higher than 2007 (shown), as well as higher than 2004 and 2014 (not shown – see it for yourself here). Click to enlarge.

Sea ice maps and charts tell the story of current polar bear habitat throughout the Arctic.
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Twenty good reasons not to worry about polar bears

PB  logo coloured Here’s a new resource for cooling the polar bear spin, all in one place. I’ve updated and expanded my previous summary of reasons not to worry about polar bears, which is now two years old. In it, you’ll find links to supporting information (including previous blog posts of mine that provide background, maps and extensive references), although some of the most important graphs and maps have been copied into the summary. I hope you find it a useful resource for refuting the spin and tuning out the cries of doom and gloom about the future of polar bears — please feel free to share. Pdf here of the text below.

This is the 1st anniversary of Canada providing population estimates and trends independent of the pessimistic prognostications of the IUCN/SSC Polar Bear Specialist Group (PBSG) — so let’s celebrate the recent triumphs and resilience of polar bears to their ever-changing Arctic environment.

AK PB N Shore-USFWS Barrow_labeled
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Polar bear habitat update – November 2014 average sea ice levels higher than 2003

Average polar bear habitat for November 2014 was well within two standard deviations1 and higher than 2003, according to the November report from the National Snow and Ice Data Center (line and labels added, below).

Arctic ice Nov aver_NSIDC_sm_PolarBearScience

Notice that the lowest average November level occurred in 2006not 2007 (after the second lowest September extent since 1978) and not 2012 (after the lowest September extent since 1978). Take note that the scale on the graph above does not go to zero but to a whopping ~9.5 million square km!

Quotes from the NSIDC monthy report and sea ice maps for November 2014 and 2 December 2014 below.

UPDATE 3 December 2014: CIS has issued a new ice map corrected for ice level on Hudson Bay – new map below.
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Polar bears are not in peril due to recent sea ice changes

To counter the misleading ploy used by the Sunday Times — of implying polar bears are in peril because of recent changes in Arctic sea ice (Sunday Times & The Australian, 21/22 Sept. 2014 Arctic ice cap in a ‘death spiral’) — I’ll go over again why the polar bear as a species is not threatened by declines in summer sea ice or even winter ice that is predominantly “thin” (first year) ice.

Polar Peril_Arctic ice cap in a death spiral_SundayTimes_Sept 21 2014_21_NWS_20_POLAR_1096592k
Graphic above from the Sunday Times, September 21, 2014
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Reflections on my House of Lords lecture: Healthy polar bears, less than healthy science

Here is an excerpt of an essay I wrote reflecting on the recent (11 June 2014) lecture I gave at the House of Lords in London (“Healthy polar bears, less than healthy science”). The Global Warming Policy Foundation (GWPF) has just published that 14 page essay in its entirety as its 10th such report but you can get a taste of it here.


My piece addressed the following issues that I talked about in the lecture or which came up afterwards during the question period and discussions later:

•  On what do you base your assertion that polar bear populations are “healthy”?
•  Are the media — or polar bear scientists — to blame for hyping the “polar bears are dying” meme?
•  How significant was the recent dismissal of a petition to force Canada into listing polar bears as ‘threatened with extinction’?
•  What do the recent actions of the Polar Bear Specialist Group say about their commitment to good science?
•  Is my blog helping to “self-correct” the science on polar bears?

The highlighted point is copied in full below. See the full essay here.
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“Polar bears miss the message on global warming” – my article in RANGE Magazine

Here’s an excerpt of my article “Polar bears miss the message on global warming,” just out in the Fall 2014 issue of RANGE Magazine.

AK PB N Shore-USFWS Barrow_labeled Continue reading

Polar bear habitat update – ice coverage at the beginning of this year’s critical feeding period

Polar bears are all out on the sea ice at this time of year, feeding on new-born seal pups. Here’s a look at what the ice conditions are like at this critical time.

Polar_Bear_male on sea ice_Alaska Katovik Regehr photo_April 29, 2005_sm labeled

end April extent NSIDC May 4

The ice extent is still well within two standard deviations from the 1981-2010 average, which indicates no deviation from natural variation, as the graph (below) for May 1, 2014 from the US National Snow and Ice Data Center (NSIDC) shows.

Sea ice extent 2014 May 1_NSIDC_graph

Between the official spring maximum (according to the NSIDC ) on March 21, with a total extent of 14.8 million km2, the ice slowly retreated in some regions and increased in others, while most regions remained pretty much the same. This is an important reminder that the Arctic as a whole is not a homogeneous region but one with marked regional variation.

As has been noted elsewhere (Sunshine Hours), ice in the Greenland Sea (habitat of ‘East Greenland’ bears) and the Barents Sea both increased in extent over this period. Bering Sea ice (habitat of southern ‘Chukchi Sea’ bears) declined markedly but Baffin Bay/Gulf of St. Lawrence ice (habitat of ‘Davis Strait’ bears) declined much less, as NOAA’s MASIE maps copied below show very well.

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Nature acknowledges warming hiatus, but does not explain continued declines in Arctic sea ice

Although there have been jumps and dips, average atmospheric temperatures have risen little since 1998, in seeming defiance of projections of climate models and the ever-increasing emissions of greenhouse gases.” Jeff Tollefson, January 15, 2014, Nature. [open access]

The eminent science journal Nature has finally acknowledged that global average temperatures have not behaved as predicted by climate models over the last 16 years. [h/t A. Watts]

Note that predictions of future sea ice declines and associated predictions of future polar bear declines are totally dependent on these climate models.

Here’s my question: if global temperatures have basically flat-lined since 1998, why has Arctic sea ice continued to decline?

If average global temperatures govern Arctic sea ice behavior, why was 1998 (or the year after) not the lowest September sea ice extent reached over the last 30 years? Oddly, 2012 was the lowest September extent (see graphs below, from NSIDC).

Paradoxically, not only has sea ice continued to decline since 1998 – despite the hiatus in global warming – but since 1998, all but one polar bear populations have either increased in size, not declined, or are doing very well by other measures (see previous summary post, Polar bears have not been harmed by sea ice declines).

Sea ice extent graphs for September (which all the hysteria is about) compared to selected months from March, June and November. Ranges given are approximate; note the differences in scale for each graph. NSIDC graphs, colored labels added.

Sea ice extent graphs for September (which all the hysteria is about) compared to selected months from March, June and November. Ranges given are approximate; note the differences in scale for each graph. NSIDC graphs, colored labels added.

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