Tag Archives: polar bears

Now at least 10 years with sea ice at 2050-like levels yet polar bears are still abundant

We’ve hit the seasonal Arctic sea ice minimum for this year, called this morning by US NSIDC for 19th and 23rd of Septmeber: 4.59 mkm2, the same extent as 2008 and 2010. This is not a “ho-hum” year for polar bears: it means that since 2007, they have triumphed through 10 or 11 years1 with summer ice coverage below 5.0 mkm2 —  levels that in 2007 were expected to cause catastrophic declines in numbers.

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Summer sea ice below 5.0 mkm2 were not expected to occur until about 2050, according to 2005/2006 sea ice models and polar bear specialists at the US Geological Survey (USGS). Polar bear survival models predicted 2/3 of the world’s polar bears would disappear when ice levels reached this threshold for 8 out of 10 years (Amstrup et al. 2007, 2008; Hunter 2007) but polar bears have been more resilient than expected (Crockford 2017, 2018; Crockford and Geist 2018). In fact, in many areas (like the Chukchi Sea, Barents Sea and Foxe Basin) polar bears are thriving despite dramatic declines in summer sea ice coverage (Aars et al. 2017; ACSWG 2018; Peacock et al. 2013; Regehr et al. 2016; Stapleton et al. 2016).

The sea ice models used to support the addition of polar bears to the US Endangered Species List as ‘threatened’ with extinction suggested sea ice levels from 3-5 mkm2 would not occur unti mid-century, yet they dropped before the ink was dry on the 2007 USGS Reports (ACIA 2005; Hassol 2004; Holland et al. 2006; Solomon et al. 2007; Zhang and Walsh 2006).

The ice extent charts from the University of Bremen (below) show ice that’s 50% concentration or greater at the date of the seasonal minimum (19th September): what polar bear specialists define as preferred habitat (Amstrup et al. 2007).

arctic_amsr2_visual_2018_sept_19.png

Compare the minimum shown above to the coverage predicted for 2050 and to coverage at the minimum in 2012 (the NSIDC image is here):

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Tracking polar bears in the Beaufort Sea May and June updates

At the end of June, there were nine bears remaining from the original 14 that were tagged with glue-on ear transmittors in April 2018 near Kaktovik, Alaska by US Geological Survey biologists.

putting_collar_on_polar_bear_slider_USGS

Below is the June 2018 tracking map (high resolution image is here):

Beaufort tracking USGS bear-movements-June 2018 sm

Original caption: “Movements of 9 satellite-tagged polar bears for the month of June, 2018. These bears received satellite eartag transmitters in 2018 on the spring-time sea ice of the southern Beaufort Sea. Polar bear satellite telemetry data are shown with AMSR2 remotely-sensed ice coverage for 30 June, 2018.”

See the close-up for June 2018 below:

Beaufort tracking USGS bear-movements-June 2018 closeup

As ear tags are notoriously short-lived, there may not be any remaining by the end of July but if there are, I will post the tracks. The map for May 2018 is below.
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Less Svalbard polar bear habitat during the early Holocene than now

Svalbard in the western Barents Sea has recently had less sea ice extent than it had in the 1980s, especially in the west and north, but this is not unprecedented.

Svalbard polar bear_Aars August 2015-NP058930_press release

New evidence from clams and mussels with temperature-sensitive habitat requirements confirm that warmer temperatures and less sea ice than today existed during the early Holocene period about 10.2–9.2 thousand years ago and between 8.2 and 6.0 thousand years ago (based on radio carbon dates) around Svalbard. Barents Sea polar bears almost certainly survived those previous low-ice periods, as they are doing today, by staying close to the Franz Josef Land Archipelago in the eastern half of the region where sea ice is more persistent.

As this sea ice chart for 18 April 2018 shows, ice this month has been virtually absent from the west and north coasts of the Svalbard Archipelago, while Franz Josef Land to the east is surrounded by highly concentrated pack and land-fast ice.

Barents Sea ice 2018 April 18 NIS

From a new paper by Jan Mangerud and John Svendsen (2018) [my bold]:

Svalbard, located between 74° and 81°N, is the warmest place on Earth at this latitude (Drange et al., 2013). This is because of the North Atlantic Current and large-scale atmospheric circulation which transport warm water and air masses from lower latitudes northwards across the Atlantic and along the coast of Norway to Svalbard (Figure 1). Yet, during the Holocene Thermal Maximum, the climate of Svalbard was considerably warmer than at present.

The transition from Younger Dryas cold to Holocene Thermal Maximum warm conditions took place very rapidly, according to records from nearby Greenland (Taylor et al. 1997), warming in “steps” of about five years each over a period of about 40 years. This was at least as fast, if not faster than, recent Arctic warming between the 1980s and 2015. And since polar bears of the Barents Sea and adjacent Arctic areas appear to have survived this change to Holocence Thermal Maximum conditions, it challenges the notion that recent warming has been (or will be) too fast to allow polar bears to survive without huge changes in their present distribution (Amstrup et al. 2007).
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My Financial Post op-ed: Polar bears keep thriving even as global warming alarmists keep pretending they’re dying

One powerful polar bear fact is slowly rising above the message of looming catastrophe repeated endlessly by the media: More than 15,000 polar bears have not disappeared since 2005. Although the extent of the summer sea ice after 2006 dropped abruptly to levels not expected until 2050, the predicted 67-per-cent decline in polar bear numbers simply didn’t happen. Rather, global polar bear numbers have been stable or slightly improved.

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The polar bear’s resilience should have meant the end of its use as a cherished icon of global warming doom, but it didn’t. The alarmism is not going away without a struggle. Continue reading

Early Holocene polar bear skeleton from Norway vs. other ancient remains

A press release issued yesterday (23 January 2018) by the University of Stavanger tells the story of decades of work on the most complete ancient polar bear skeleton in the world, found in 1976 in southern Norway, that culminated in an articulated museum display. This specimen was described in my research paper, Annotated Map of Ancient Polar Bear Remains of the World (Crockford 2012), which shows how many very early Holocene remains have been found outside current polar bear range.

Finn the ice age polar bear skeleton_U Stavanger_photo 2

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Franz Josef Land is a sea ice refugium for most pregnant Barents Sea polar bears

Consensus polar bear expert Andrew Derocher has been busy over the last few weeks, expounding a story of doom regarding Svalbard area polar bears (e.g. here and here), ridiculing the suggestion that Franz Josef Land is viable alternate habitat for Barents Sea bears, especially pregnant females looking for a place to den and give birth. But the facts say otherwise.

Svalbard polar bear_Aars August 2015-NP058930_press release

Below are the long answers, with references and ice maps, to the questions Derocher asked in his 21 December 2017 tweet (above), a refreshing change from the ‘take my word for it, I’m the official expert’ answer one gets from him, along with derogatory slurs directed at those who don’t share his pessimism.

UPDATED 1 February 2019. Two references added.

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Twenty reasons not to worry about polar bears, the 2017 update

Cover image_Twenty Reasons_polarbearscienceJust in time for Polar Bears International’s self-proclaimed fall Polar Bear Week (5-11 November 2017), here’s a new resource for cooling the polar bear spin. I’ve updated my 2015 summary of reasons not to worry about polar bears, which is now more than two years old. In this new version, you will find links to supporting information, including published papers and fully referenced blog posts of mine that provide background, maps and bibliographies, although some of the most important graphs and maps have been reproduced here. I hope you find it a useful resource for refuting the pessimism and prophecies of catastrophe about the future of polar bears. Please feel free to share it.

As global leaders meet in Bonn for COP23 (6-17 November 2017), it’s time to celebrate the proven resilience of polar bears to their ever-changing Arctic environment.

Twenty Reasons: the bullet points

  1. Polar bears are still a conservation success story: there are more polar bears now than there were 40 years ago.
  2. Fewer populations are in decline than in 2010 (only one, officially) and only six are data deficient (down from nine).
  3. Abrupt summer sea ice decline has not affected polar bear numbers as predicted: even though sea ice levels dropped to mid-century levels in 2007, the expected decimation of polar bears failed to occur.
  4. The Chukchi Sea population is thriving despite a pronounced lengthening of the ice-free season since 2007.
  5. Less sea ice in the summer in the Chukchi Sea has meant a healthy prey base for polar bears because ringed seals feed primarily in the ice-free season.
  6. Polar bears have shown themselves to be adaptable to changing ice conditions in several regions.
  7. Southern Beaufort numbers have rebounded since the last survey count.
  8. Barents Sea numbers have probably increased since 2005 and have definitely not declined despite much less sea ice cover.
  9. There is no evidence that record-low summer sea ice in 2012 had a harmful effect on Southern Beaufort bear numbers.
  10. Other species are being negatively impacted by high polar bear numbers, especially nesting sea birds and ducks.
  11. Western Hudson Bay population numbers have been stable since 2004, despite what scientists are telling the media.
  12. Hudson Bay sea ice has not changed since about 1999: breakup dates and freeze-up dates are highly variable but the ice-free period was not any longer in 2015 than it was in 2004. However, this fall freeze-up is shaping up to be the earliest in decades.
  13. Problem bears in Churchill are not lean or starving.
  14. Churchill Manitoba had the most problem bears in 1983 and 2016, which were late freeze-up years, but many of the incidents in 2016 can be attributed to increased vigilance on the part of patrol officers after an attack in 2013.
  15. There have been only marginal sea ice declines during the feeding period in spring, when polar bears need sea ice the most.
  16. The is no evidence that subsistence hunting is affecting bear populations.
  17. Stressful research methods have been curtailed in much of Canada.
  18. There have been no reports of polar bear cannibalism since 2011.
  19. Polar bears appear unaffected by pollution: studies suggest only that harm is theoretically possible, not that it has happened.
  20. Polar bears have survived past warm periods, which is evidence they have the ability to survive future warm periods.

Conclusion

  • Polar bears are thriving: they are not currently threatened with extinction.
  • Tens of thousands of polar bears did not die as a result of more than a decade of low summer sea ice, as was predicted.
  • Polar bears don’t need sea ice in late summer/early fall as long as they are well-fed in the spring.

[full text below, pdf with footnotes and references here]

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