Polar bears are unlikely to go extinct more than 18 years ago when Arctic sea ice hits ‘tipping point’ – Would you plummet for that?
Susan Crockford
All predictions of disaster aside, in fact, polar bears are not close to extinction compared to 2005 when sea ice was in the Arctic once again steadfastly resisted slide over a catastrophic ‘tipping point’ – or ‘spiral of death’like some chickens keep calling it.
In fact, the summer sea ice trend has been fairly flat since 2007, with about 42% less ice cover than it was in 1979, but polar bears in many areas are doing better now than they were. with 2005, especially in Davis Strait, Barents Sea and Chukchi and Canadian Arctic Islands.
There is no ‘tipping point for the North Pole’ summer sea ice
National Oceanic and Atmospheric Association (NOAA) identify three periods in minimal sea ice: Between 1979 and 1992, sea ice lost about 6% per decade. From 1993 to 2006, the decline accelerated to 13.3%. But between 2007 and 2020, the slope drops to just 4%. News MongaBayJuly 15, 2021.
That flat trend has only continued, as the chart below shows, modified from a chart published by the US Snow and Ice Data Center (NSIDC). in 2019 – see the original here – show the September average (Not the minimum), so while we don’t have a figure for 2022 yet, it is likely to be close to the figure for 2021:
Minimum sea ice by 2022
NSIDC yesterday reported that Arctic sea ice reached its minimum on September 19 of this year, including 4.68mk2. The University of Bremen (see chart below) measured the range at 4.87mk2 on this date but the small difference doesn’t really matter: the shape and aerial coverage of the ice on this day compared to the year 2005 is what I am emphasizing here.
Minimum sea ice in 2005
Minimum ice cover achieved on September 22, 2005 (U. Bremen):
Predictions based on sea ice conditions in 2005
Half of the predictions for future sea ice cover (for 2050) were exceeded in 2007 and the authors of the 2007 USGS conservation report on polar bears (Amstrup et al. 2007) said: “This suggests that our predictions about the future state of polar bears may be conservative.” In other words, Amstrup and colleagues think the future is likely to be even worse than they predicted in their report: even more More than two-thirds of the world’s polar bears will be lost by 2050.
For 15 years in a row, summer seas are 42% less icy
As the chart below by Stroeve and colleagues shows, the summer Arctic sea ice loss models used to predict dire futures for polar bears, in 2007, were quickly wrong. deviates from the observations: it really is worse than they thought!
As it happened, polar bear experts are wrong (Crockford 2017, 2019): polar bears are more flexible and resilient than anticipated and after 15 years summer sea ice drops to ‘catastrophic’ levels (about 42% less ice than in 1979 for at least 8 years on 10), many bear populations are better off than before. Davis StraitBarents Sea and Chukchi . Sea Bear is doing great: Barents sea bear especially thriving even though the sea has by far lost the most ice of any arctic region (e.g. Lippold et al 2019; Peacock et al 2013; Regehr et al 2018; Rode et al 2014). This is Not what was predicted.
Inference: Despite the warming of the Arctic four times faster than the rest of the world with rising CO2 levels and about 42% less summer ice than in 1979, there is currently no ‘climate emergency’ for polar bears and the species not close to extinction compared to 15 years ago.
Presenter
Amstrup, SC, Marcot, BG & Douglas, DC 2007. Forecasting polar bears’ snow and ice conditions at selected times in the 21st century. United States Geological Survey. Reston, VA. Pdf here
Crockford, SJ 2017. Test the hypothesis that regular sea ice cover of 3-5 mkm2 leads to a decline of more than 30% in polar bear population size (Ursus maritimus). PeerJ Preprint January 19, 2017. Doi: 10.7287 / peerj.preprints.2737v1 Open access. https://peerj.com/preprints/2737/
Crockford, SJ 2019. The polar bear disaster has never happened. Global Warming Policy Fund, London. Available in paperback and eBooks formats.
Lippold, A., Bourgeon, S., Aars, J., Andersen, M., Polder, A., Lyche, JL, Bytingsvik, J., Jenssen, BM, Derocher, AE, Welker, JM and Routti, H. 2019. Transient trends of persistent organic pollutants in Barents Sea polar bears (Ursus maritimus) associated with changes in feeding habits and body condition. Environmental Science and Technologyy 53 (2): 984-995.
Peacock, E., Taylor, MK, Laake, J. & Stirling, I. 2013. Population ecology of polar bears in Davis Strait, Canada and Greenland. Wildlife Management Magazine 77: 463–476.
Regehr, EV, Hostetter, NJ, Wilson, RR, Rode, KD, St. Martin, M., Converse, SJ 2018. Population aggregation modeling provides the first empirical estimates of polar bear survival and abundance 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, KD, Regehr, EV, Douglas, D., Durner, G., Derocher, AE, Thiemann, GW and Budge, S. 2014. Differences in the response of Arctic top predators to 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
Stroeve, J., Holland, MM, Meier, W., Scambos, T. and Serreze, M. 2007. Arctic sea ice decline: Faster than forecast. Geophysical research letter 34: L09501. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2007GL029703
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