Outlandish ‘tipping point’ rhetoric is about to be regurgitated once again during the promotion of the latest IPCC report, due today. Tipping points are those theoretical climate thresholds that, when breeched, cause widespread catastrophe; they are mathematical model outputs that depend on many assumptions that may not be plausible or even possible.
Polar bears often get caught up in motivational tales of sea ice tipping points.
Tipping points are not facts: they are scary stories made to sound like science.
This is why Sir David Attenborough has totally embraced the tipping points narrative. He even made a movie fully devoted to them, called, Breaking Boundaries – The Science of Our Planet. Tipping points are the animal tragedy porn of mathematical models and Attenborough has adopted them both.
Attenborough and his cronies want you to be afraid of climate change instead of thinking about what they actually mean by ‘action’, ‘climate-neutral’ and ‘net zero’. They want free reign to rid the world of fossil fuels and the more frightened you are by their implausible narratives, the more likely they are to succeed.
Remember the original scary polar bear story: the ice is melting faster than we thought and 2/3 of the bears are going to die!
But contrary to those predictions, polar bears survived a loss of summer sea ice of more than 40% since 1979 without any decline in global population size (Amstrup et al. 2007; Crockford 2017, 2019, 2021).
We’ve had 14 years of sea ice coverage in summer that polar bear specialists insisted would devastate the species and yet studies on the bears in Arctic areas most drastically affected by ice loss (Barents Sea and Chukchi Sea) show they are thriving, not struggling to survive (Aars 2018; Crockford 2021; Regehr et al. 2016, 2018; Rode et al. 2014, 2018).
The newest polar bear model (Molnár et al. 2020) is no more believable than the first one and no more likely to present an accurate picture of the future for polar bears.
Mathematical models are not facts (Curry 2017; Hausfather and Peters 2020).
Future climate is not any more likely to be accurately predicted by models than future polar bear survival.
Aars, J. 2018. Population changes in polar bears: protected, but quickly losing habitat. Fram Forum Newsletter 2018. Fram Centre, Tromso. Download pdf here (32 mb).
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
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. 2021. The State of the Polar Bear Report 2020. Global Warming Policy Foundation Report 48, London. pdf here.
Curry, J. 2017. Climate Models for the Layman. Global Warming Policy Foundation Briefing #24. London. pdf here.
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
Molnár, P.K., Bitz, C.M., Holland, M.M., Kay, J.E., Penk, S.R. and Amstrup, S.C. 2020. Fasting season length sets temporal limits for global polar bear persistence. Nature Climate Change. https://doi.org/10.1038/s41558-020-0818-9
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.
Regehr, E.V., Hostetter, N.J., Wilson, R.R., Rode, K.D., St. Martin, M., Converse, S.J. 2018. Integrated population modeling provides the first empirical estimates of vital rates and abundance for polar bears in the Chukchi Sea. Scientific Reports 8 (1) DOI: 10.1038/s41598-018-34824-7 https://www.nature.com/articles/s41598-018-34824-7
Rode, K.D., Regehr, E.V., Douglas, D., Durner, G., Derocher, A.E., Thiemann, G.W., and Budge, S. 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., 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. 2018. Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity. Global Change Biology http://onlinelibrary.wiley.com/doi/10.1111/gcb.13933/full