Dr. Susan Crockford
Experts who used the American Endangered Species Act (ESA) to list polar bears as ‘threatened’ in May 2008 were mistaken: sea ice authorities got their predictions wrong about future ice extent and polar bear specialists erroneously declared that two-thirds of polar bears would disappear if summer sea ice declines continued unabated.
By 2007, there was even less summer sea ice than computer models of the day had predicted (Stroeve et al. 2007, see red line on graph below) and in 2012, it dropped to just above 3 mkm2.
Updated sea ice predictions published in 2014 by the Stroeve team (see below) went to the other extreme, using totally implausible RCP 8.5 scenarios to predict a virtually ice-free Arctic (< 1 mkm2 ice extent) before 2040, which seem just as likely to be just as wrong as their 2007 attempt (Hausfather and Peters 2020; Pielke and Ritchie 2021; Stroeve et al. 2007, 2014; Swart et al. 2015).
In fact, for 12 years out of the last 15, summer ice extent has been below 5.0 mkm2 (often well below), which polar bear experts had not anticipated would happen until at least 2050 (Amstrup et al. 2006).
In 2012, NOAA sea ice experts summarized this sea ice loss as “reduced by nearly 50%” since 1979:
Despite this dramatic decline in sea ice, polar bears are still abundant and thriving because polar bear specialists got it wrong about the bears’ need for this habitat in summer (Crockford 2017, 2019; Crockford and Geist 2018). Polar bear turned out to be more flexible and resilient than predicted and many subpopulations are better off than before. Davis Strait and Chukchi Sea bears are doing very well: Barents Sea bears in particular are thriving despite by far the most sea ice loss of any Arctic region (e.g. Conn et al. 2021; Frey et al. 2022; Haavik 2022; Lippold et al. 2019; Peacock et al. 2013; Regehr et al. 2018; Rode et al. 2014, 2018, 2021, 2022).
This was not what had been predicted when the bears were listed as ‘threatened’ in 2008.
Conclusion: Despite the Arctic warming four times as fast as the rest of the world with rising CO2 levels and almost 50% less summer ice than there was in 1979, polar bears are no closer to extinction than they were 15 years ago, according to the results of field studies. There is no existential emergency for polar bears or any other Arctic sea mammals due to declining summer sea ice, despite continued messages of doom from remorseless experts.
References
Amstrup, S.C., Marcot, B.G. & Douglas, D.C. 2007. Forecasting the rangewide status of polar bears at selected times in the 21st century. US Geological Survey. Reston, VA. Pdf here
Conn, P.B., Chernook, V.I., Moreland, E.E., et al. 2021. Aerial survey estimates of polar bears and their tracks in the Chukchi Sea. PLoS ONE 16(5): e0251130. https://doi.org/10.1371/journal.pone.0251130
Crockford, S.J. 2017. 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 19 January 2017. Doi: 10.7287/peerj.preprints.2737v1 Open access. https://peerj.com/preprints/2737/
Crockford, S.J. 2019. The Polar Bear Catastrophe That Never Happened. Global Warming Policy Foundation, London. Available in paperback and ebook formats.
Crockford, S.J. and Geist, V. 2018. Conservation Fiasco. Range Magazine, Winter 2017/2018, pg. 26-27. Pdf here.
Frey, K.E., Comiso, J.C., Cooper, L.W., et al. 2022. Arctic Ocean primary productivity: the response of marine algae to climate warming and sea ice decline. 2022 NOAA Arctic Report Card, https://doi.org/10.25923/0je1-te61
Haavik, E. 2022. ‘Svalbard’s polar bears persist as sea ice melts — but not forever. The World, 21 July.
Hausfather, Z. and Peters, G.P. 2020. Emissions – the ‘business as usual’ story is misleading [“Stop using the worst-case scenario for climate warming as the most likely outcome — more-realistic baselines make for better policy”]. Nature 577: 618-620. https://www.nature.com/articles/d41586-020-00177-3
Lippold, A., Bourgeon, S., Aars, J., et al. 2019. Temporal trends of persistent organic pollutants in Barents Sea polar bears (Ursus maritimus) in relation to changes in feeding habits and body condition. Environmental Science and Technology 53(2):984-995.
Pielke, R., and Ritchie, J. 2021. How climate scenarios lost touch with reality. Issues in Science and Technology 37(4): 74-83. https://issues.org/climate-change-scenarios-lost-touch-reality-pielke-ritchie/
Pielke Jr, R., and Ritchie, J. 2021. Distorting the view of our climate future: The misuse and abuse of climate pathways and scenarios. Energy Research & Social Science72: 101890. https://www.sciencedirect.com/science/article/abs/pii/S2214629620304655
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://rsbl.royalsocietypublishing.org/content/12/12/20160556 Supplementary data here.
Rode, K.D., Regehr, E.V., Douglas, D., et al. 2014. Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations. Global Change Biology 20(1):76-88. http://onlinelibrary.wiley.com/doi/10.1111/gcb.12339/abstract
Rode, K.D., Olson, J., Eggett, D., et al. 2018. Den phenology and reproductive success of polar bears in a changing climate. Journal of Mammalogy 99(1):16-26. here.
Rode, K. D., Regehr, E.V., Bromaghin, J. F., et al. 2021. Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea. Global Change Biology 27:2684–2701. https://doi.org/10.1111/gcb.15572
Rode, K.D., Douglas, D.C., Atwood, T.C., et al. 2022. Observed and forecasted changes in land use by polar bears in the Beaufort and Chukchi Seas, 1985-2040. Global Ecology and Conservation 40: e02319. https://doi.org/10.1016/j.gecco.2022.e02319
Stroeve, J., Holland, M.M., Meier, W., Scambos, T. and Serreze, M. 2007. Arctic sea ice decline: Faster than forecast. Geophysical Research Letters 34:L09501. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2007GL029703
Stroeve, J.C., Markus, T., Boisert, L., et al. 2014. Changes in Arctic melt season and implications for sea ice loss. Geophysical Research Letters 10.1002/2013GL058951. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013GL058951
Swart, N.C., Fyfe, J.C., Hawkins, E. et al. 2015. Influence of internal variability on Arctic sea ice trends. Nature Climate Change 5:86-89.
