Tales of doom and gloom about polar bears reflect what some people think might happen in the future, not what is happening right now. Currently, polar bears are doing just fine despite the low summer sea ice coverage they’ve experienced since 2007 (Crockford 2017a; York et al. 2016). In other words, there has been no global population decline as predicted: officially, the numbers were 22,000-31,000 (or 26,500 average) in 2015 (Wiig et al. 2015) but about 28,500 when estimates published since then are included (Aars et al. 2017; Dyck et al. 2017; Matishov et al. 2014; SWG 2016), up from about 22,500 in 2005).
This increase might not be statistically significant but it is most assuredly not the decrease in abundance that was predicted by ‘experts’ such as Steve Amstrup and colleagues (Amstrup et al. 2007), making it hard to take subsequent predictions of impending catastrophe seriously (e.g. Atwood et al. 2016; Regehr et al. 2016; Wiig et al. 2015).
The doomsayers can’t stand to have someone provide the public with unbaised evidence of this failure so they attack my scientific integrity with an academically weak and aggressively vindictive ‘peer-reviewed’ paper (Harvey et al. 2017, in press) that you’ll hear more about in the new year.
Bottom line: 2017 saw abundant good news stories about polar bears, which I’ve summarized below. See also Crockford 2017b: Twenty reasons not to worry about polar bears, the 2017 update and my 2017 block-buster video, Polar Bear Scare Unmasked: The Saga of a Toppled Global Warming Icon:
- Baffin Bay polar bear numbers were found in 2013 to be stable: the abundance of polar bears did not decline as expected due to over-hunting or summer sea ice loss (SWG 2016) and the picture of the lone Baffin Bay bear dying of what was probably a fatal illness that got splashed across newspapers around the world is not typical of the bears that make up the Baffin Bay subpopulation:
2,826 bears estimated in 2013 (95% CI = 2,059-3,593)
[vs. 1546 expected by 2004 (95% CI = 690-2,402) and 2,074 estimated in 1997 (95% CI = 1,553-2,595)
- Kane Basin polar bear numbers are stable or increasing because of less multiyear ice (polar bears and their prey do best with first year ice): the abundance of polar bears did not decline as expected due to loss of sea ice, it increased 118%:
357 bears estimated in 2013 (95% CI: 221 – 493) [vs. 164 in 1997 (95% CI: 94 – 234)] This increase in abundance of Kane Basin bears suggests that other subpopulations in the Canadian Arctic Archipelago ” target=”_blank” rel=”noopener”>may be doing similarly well with less summer sea ice.
- Wrangel Island polar bears that spend the summer increased dramatically from about 200-300 in 2012 and 2013 (Ovsyanikov and Menyushina 2015) to 589 in the fall of 2017 (Regehr 2017, Daily Mail, 23 November 2017), a not so unusual occurrance since in 2007 an estimated 550-600 bears were counted on the island (Ovsyanikov 2010).
Two litters of four cubs each were seen on Wrangel in September 2017 — an almost unheard of rarity — when at least 200 bears in good condition (see above photo) were spotted descending on a beached whale carcass. USFWS biologist Eric Regehr told the Daily Mail (23 November 2017) that the polar bear population in the shared US-Russian Chukchi Sea currently “appears to be productive and healthy.“ Fabulous news for a regional population that has suffered some of the most dramatic declines in summer sea ice across the Arctic (Stein et al. 2017).
- Hudson Bay froze over as early this fall as it did in the 1980s (Castro de la Guardia et al. 2017; Cherry et al. 2013) which allowed most Western and Southern Hudson Bay polar bears to resume seal hunting 4 weeks earlier than last year. Western Hudson Bay bears leave the shore within about 2 days of sea ice concentration reaching 10% (Castro de la Guardia 2017; Cherry et al. 2013), although as noted above, Southern Hudson Bay bears leave when it reaches about 5% (Obbard et al. 2015, 2016): in other words, the bears leave shore as soon as they possibly can. This year, there was enough ice by 8 November for many bears to leave shore and by 10 November, most bears were on their way. According to data for 1979-2015 (Castro de la Guardia 2017), in the 1980s the mean date that bears left the ice at freeze-up (10% sea ice coverage in WHB) was 16 November ± 5 days while in recent years (2004-2008) the mean date of leaving was 24 November ± 8 days, a difference of 8 days. This also means that a freeze-up date of 10-12 November (Day 314-316) this year was one of the earliest freeze-up dates since 1979 (the earliest being 6 November, Day 310).
Listen to CBC interview from a visitor to Churchill during freeze-up 2017 here: http://ift.tt/2pYql7O
- Newfoundland and Labrador had an astonishing number of polar bear sightings and problem bears onshore this spring, according to local news reports (discussed here and here) due to unusually cold conditions and heavy sea ice, probably more sightings than any time since the mid-1800s. Oddly, some commentators chose to blame this phenomenon on global warming and/or poor ice conditions. Other rare onshore sightings were also reported in 2017.
- Western Hudson Bay polar bear numbers are still stable according to a 2016 survey (Dyck et al. 2017): an apparent ‘decline’ since 2011 was not statistically significant.1
- Barents Sea numbers have probably increased since 2005 and have definitely not declined despite much less sea ice cover: a 42% increase in Svalbard area numbers in 2015 was considered not statistically significant (Aars et al. 2017). I’ll discuss this phenomenon in more detail in the new year.
- Official status tables need to be updated: the new Baffin Bay, Kane Basin, and Barents Sea population assessment data released or published in 2017 meant that fewer populations are now considered to be “in decline” than in 2014 (only one, officially — Southern Beaufort Sea, SB, Rode et al. 2017) and only six are data deficient (down from nine), which means the Environment Canada status map below (2014) will need updating [BS, KB, and KS are no longer data deficient; BB is likely stable, not declining]
- This year also saw the release of my detailed polar bear science book for those who want to understand why contrary to all of the predictions, polar bears are thriving: Polar Bears: Outstanding Survivors of Climate Change (in paperback and several ebook formats. The 2016 popular version suitable for younger children, Polar Bear Facts & Myths, was translated into French and German in 2017.
- Lastly, 2017 saw a return to sound, science-based conservation policy when the US Fish and Wildlife Service decided not to list the Pacific walrus (a minor prey species for polar bears) as ‘threatened’ with extinction under the ESA:
“U.S. Fish and Wildlife Service officials said they cannot determine with certainty that walruses are likely to become endangered “in the foreseeable future,” which the agency defines as the year 2060.”
(CBC, 4 October 2017).
Footnote 1. Because the 2011 and 2016 Western Hudson Bay aerial surveys used somewhat different methods, the only population size numbers that can be compared are these: 2011 (estimate 949, range 618-1280) and 2016 (estimate 842, range 562-1121). The slight decline apparent over 5 years (11%) was not statistically significant (Dyck et al. 2017, pg. 3, 37). When differences in methodology and assumptions are taken into account, there is no evidence to suggest the estimate for 2016 for 842 bears is different from the 2011 estimate of 1030 bears (Stapleton et al. 2014), neither of which is statistically different from the estimate of 935 calculated in 2004 (Regehr et al. 2007).
Aars, J., Marques,T.A, Lone, K., Anderson, M., Wiig, Ø., Fløystad, I.M.B., Hagen, S.B. and Buckland, S.T. 2017. The number and distribution of polar bears in the western Barents Sea, Polar Research 36:1, 1374125, DOI:10.1080/17518369.2017.1374125
Amstrup, S.C.,Marcot, B.G. and Douglas,D.C. 2007. Forecasting the rangewide status of polar bears at selected times in the 21st century. Administrative Report, US Geological Survey. Reston, Virginia. 8.8 MB pdf here [may no longer be available online]
Atwood, T.C., Marcot, B.G., Douglas, D.C., Amstrup, S.C., Rode, K.D., Durner, G.M. et al. 2016. Forecasting the relative influence of environmental and anthropogenic stressors on polar bears. Ecosphere 7(6): e01370. http://ift.tt/2tPupqU
Crockford, S. 2017a. Testing the hypothesis that routine sea ice coverage of 3-5 mkm2 results in a greater than 30% decline in population size of polar bears (Ursus maritimus). PeerJ Preprints 2 March 2017. Doi: 10.7287/peerj.preprints.2737v3
Crockford, S. 2017b. Polar Bear Scare Unmasked: The Saga of a Toppled Global Warming Icon. Youtube video, February, Global Warming Policy Foundation http://ift.tt/2pWjUST
Crockford, S. 2017c. The Death of a Climate Icon. Youtube video, August, Global Warming Policy Foundation http://ift.tt/2EdJ5mN
Crockford 2017d. Twenty good reasons not to worry about polar bears: an update. Global Warming Policy Foundation Briefing Paper 28. 6 November 2017. pdf with references.
Dyck, M., Campbell, M., Lee, D., Boulanger, J. and Hedman, D. 2017. 2016 Aerial survey of the Western Hudson Bay polar bear subpopulation. Final report, Nunavut Department of Environment, Wildlife Research Section, Iglolik, NU. http://ift.tt/2s5QiiX
Federal Register announcement (USFWS; 4 October 2017) “Endangered and Threatened Wildlife and Plants; 12-Month Findings on Petitions to List 25 Species as Endangered or Threatened Species” [pdf]
Harvey, J.A., van den Berg, D., Ellers, J., Kampen, R., Crowther, T.W., Roessingh, P., Verheggen, B., Nuijten, R. J. M., Post, E., Lewandowsky, S., Stirling, I., Balgopal, M., Amstrup, S.C., and Mann, M.E. 2017. Internet blogs, polar bears, and climate-change denial by proxy. Bioscience. DOI: 10.1093/biosci/bix133 Available here. Supplementary data file here and data for the principal component analsysis is here and the R code is available here
Matishov, G.G., Chelintsev, N.G., Goryaev, Yu. I., Makarevich, P.R. and Ishkulov, D.G. 2014. Assessment of the amount of polar bears (Ursus maritimus) on the basis of perennial vessel counts. Doklady Earth Sciences 458 (2):1312-1316. [paywalled]
MacCracken et al. 2017. USFWS Species Assessment Report for the Pacific Walrus (final), May 2017
Obbard, M.E., Stapleton, S., Middel, K.R., Thibault, I., Brodeur, V. and Jutras, C. 2015. Estimating the abundance of the Southern Hudson Bay polar bear subpopulation with aerial surveys. Polar Biology 38:1713-1725.
Obbard, M.E., Cattet, M.R.I., Howe, E.J., Middel, K.R., Newton, E.J., Kolenosky, G.B., Abraham, K.F. and Greenwood, C.J. 2016. Trends in body condition in polar bears (Ursus maritimus) from the Southern Hudson Bay subpopulation in relation to changes in sea ice. Arctic Science, in press. 10.1139/AS-2015-0027
Ovsyanikov, N. 2010. Polar bear research on Wrangel Island and in the central Arctic Basin. In, Proceedings of the 15th meeting of the Polar Bear Specialists Group IUCN/SSC, 29 June-3 July, 2009, edited by Obbard, M.E., Theimann, G.W., Peacock, E. and DeBryn, T.D., pp. 171-178. Gland, Switzerland and Cambridge UK, IUCN. pdf here.
Ovsyanikov, N.G. and Menyushina, I. E. 2015. Demographic processes in Chukchi-Alaskan polar bear population as observed in Wrangel Island region. pg. 37-55, In: Marine Mammals of the Holarctic, Collection of Scientific Papers. Vol. 2. Moscow. pdf here.
Regehr, E.V., Lunn, N.J., Amstrup, S.C. and Stirling, I. 2007. Effects of earlier sea ice breakup on survival and population size of polar bears in Western Hudson Bay. Journal of Wildlife Management 71:2673-2683.
Regehr, E.V., Laidre, K.L, Akçakaya, H.R., Amstrup, S.C., Atwood, T.C., Lunn, N.J., Obbard, M., Stern, H., Thiemann, G.W., & Wiig, Ø. 2016. Conservation status of polar bears (Ursus maritimus) in relation to projected sea-ice declines. Biology Letters 12: 20160556. http://ift.tt/2h5p1bk
Rode, K. D., R. R. Wilson, D. C. Douglas, V. Muhlenbruch, T.C. Atwood, E. V. Regehr, E.S. Richardson, N.W. Pilfold, A.E. Derocher, G.M Durner, I. Stirling, S.C. Amstrup, M. S. Martin, A.M. Pagano, and K. Simac. 2017. Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity. Global Change Biology in press http://ift.tt/2pWRKXJ
Stapleton S., Atkinson, S., Hedman, D., and Garshelis, D. 2014. Revisiting Western Hudson Bay: using aerial surveys to update polar bear abundance in a sentinel population. Biological Conservation 170:38-47. http://ift.tt/1uHIkdS
Stein, R., Fahl, K., Schade, I., Manerung, A., Wassmuth, S., Niessen, F. and Nam, S-I. 2017. Holocene variability in sea ice cover, primary production, and Pacific-Water inflow and climate change in the Chukchi and East Siberian Seas (Arctic Ocean). Journal of Quaternary Science 32:362-379. DOI: 10.1002/jqs.2929 http://ift.tt/2lwzOvv
SWG [Scientific Working Group to the Canada-Greenland Joint Commission on Polar Bear]. 2016. Re-Assessment of the Baffin Bay and Kane Basin Polar Bear Subpopulations: Final Report to the Canada-Greenland Joint Commission on Polar Bear. +636 pp. http://ift.tt/2lTHatD9
Wiig, Ø., Amstrup, S., Atwood, T., Laidre, K., Lunn, N., Obbard, M., et al. 2015. Ursus maritimus. The IUCN Red List of Threatened Species 2015: e.T22823A14871490. Available from http://ift.tt/SxGLdd [accessed Nov. 28, 2015]
York, J., Dowsley, M., Cornwell, A., Kuc, M. and Taylor, M. 2016. Demographic and traditional knowledge perspectives on the current status of Canadian polar bear subpopulations. Ecology and Evolution 6(9):2897-2924. DOI: 10.1002/ece3.2030
December 29, 2017 at 03:49PM