Reposted from Polar Bear Science

Posted on May 10, 2021 | 

The beginning of this month was the 15th anniversary of the day the IUCN declared polar bears ‘vulnerable’ to extinction because of climate change, the first time such a designation had ever been made. It was based on the opinion of polar bear specialists who examined the vague information available at the time and decided that in 45 years the bears might be in serious trouble. This decision changed the way the IUCN assessed species risk and led to mass confusion for the general public, who falsely assumed polar bear numbers had already declined by a huge amount.

The Polar Bear Specialist Group was created in 1968 as a unit of the International Union for the Conservation of Nature (the IUCN), who had just developed a “Red List” of threatened and endangered species. The PBSG negotiated the 1973 International treaty to protect polar bears from unregulated hunting, a very real threat they’d been subjected to for decades.

Polar bears were first listed in 1982 as ‘vulnerable’ by the IUCN – a category equivalent to ‘threatened’ in the US. They remained in that category until 1996, when it became clear that polar bear numbers had recovered substantially. Due to the population rebound, polar bear status changed to ‘lower risk’ in 1996 (now known as ‘least concern’) and it remained there for 10 years: polar bears had been saved.

PBSG members were clearly not happy that polar bears no longer qualified as ‘vulnerable’ (this is apparent in their meeting reports) so in 2005, they recommended to the IUCN that polar bears be uplisted back to ‘Vulnerable’ on the basis of population declines expected to follow from modeled sea ice loss due to expectations of global warming (see below, from the ACIA 2005 report). Although this assessment merely reflected the opinion of PBSG members of what might happen in the future, it was accepted by the IUCN in 2006 as if it were supported by a detailed scientific analysis (Aars et al. 2006; Crockford 2017, 2019).

Without a shred of irony, on 1 May 2006 the IUCN reported two familiar animals among 530 added to the list of endangered species that year: the polar bear, based on the opinion of scientists, informed by climate models, that their numbers would decline by more than 30% over the next 45 years and the common hippo, based on an actual decline of more than 95% in the Congo. Both were to be listed as ‘vulnerable’ – one based on facts of a catastrophic local decline and the other based on prophesy.

Using ‘future threats’ based on climate models to declare a species threatened with extinction had never been done before – by the IUCN or anyone else. Here are some of the stories from that eventful time:

Fossil fuel addiction driving polar bears to extinction says WWF-Canada (WWF, 4 May 2006)

Polar bears gain ‘vulnerable’ status on world list of endangered species (CBC, 1 May 2006)

Polar bears sink deeper into danger (NATURE News, 2 May 2006)

One reason behind the PBSG decision to uplist polar bears to the ‘Vulnerable’ category was undoubtedly the knowledge that in early 2005, three activist environmental groups (Center for Biological Diversity, Greenpeace, and Natural Resources Defense Council) filed a petition to list polar bears as threatened under the US Endangered Species Act (the ESA). Later that year, the groups sued the US government for failing to address their concerns within the time frame required under ESA rules.

Now that they knew it could be done, in 2007 American biologists at the US Geological Survey (the USGS) used the IUCN “future threats” strategy to support the prediction that polar bears would be threatened with extinction within 3 polar bear generations or 45 years due to predicted sea ice loss (Amstrup et al. 2007). This time they made a model to support their opinions but it was a particular kind of model that could treat opinions as if they were facts (a ‘Bayesian’ model). I have shown that their prediction (that 2/3 of the world’s polar bears would disappear when sea ice dropped by about 40% and stayed there for 10 years – which was not expected to occur until 2050 but instead happened in 2007) failed in rather spectacular fashion (Crockford 2017, 2019; Crockford and Geist 2018).

In 2015, the IUCN commissioned another assessment and this time, they not only demanded that a mathematical model be used to predict future declines but that facts rather than opinions be used: a Bayesian model would not be acceptable. The official global population estimate used by the IUCN in 2015 was 22,000-31,000 (or an average of 26,000) and the worst they could predict for the future was that by 2050, there was a 70% chance that the population would decline by 30% or more (Wiig et al. 2015; Regehr et al. 2016). They did not acknowledge that a 30% decline for most modern population counts would not even be statistically significant (Crockford 2020:15). In addition, they underplayed the fact that they had simply assumed summer sea ice would continue to decline in a linear fashion: no climate sea ice models were actually utilized.

Fat Svalbard polar bears.

Now, in 2021, polar bear numbers are the highest they’ve been in 60 years. Recent survey results would put the global average at about 30,000 (Crockford 2021): up a little from 26,000 but not by a significant amount. However, a plausible argument can be made that this number is likely to be much higher – possibly as high as 58,000 (Crockford 2017, 2019, 2020:3).  

Red List status for polar bears in 2006 provided employment for biologists and increased donations for conservation charities but nothing for the bears that the international treaty in 1973 hadn’t already done. Protection from over-hunting was what the bears needed: most populations are still recovering from the wanton slaughter that started more than a century ago.

In other words, I don’t see any positive effect on the bears from being listed by the IUCN: they were already well protected by national laws and international treaties put in place before 2006. The concern for future polar bear survival was always about predicted low sea ice levels in the future but even after 15 years of moderately low summer sea ice (about 40% less than 1979) we have not yet seen any species-wide effects that can be attributed conclusively to climate change.  

What we’ve learned over the last 15 years is that polar bears only require sea ice until about mid-May or mid-June (depending on the latitude) and again in the late fall (November) through the winter. As long as ice is present at those times the bears will be fine. The idea that summer sea ice is essential for polar bear survival was an early assumption made by polar bear specialists that turned out to be wrong.

As I explained in my book, The Polar Bear Catastrophe That Never Happened, if polar bears really required as much summer ice as IUCN biologists assumed back in 2006, there would be fewer than 10,000 bears remaining – and that simply didn’t happen.

Climate change is unlikely to effect the future of polar bears unless there is much less ice by mid-May, which does not look likely to happen any time soon based on current conditions (see below):


Aars, J., Lunn, N. J. and Derocher, A.E. (eds.) 2006. Polar Bears: Proceedings of the 14th Working Meeting of the IUCN/SSC Polar Bear Specialist Group, 20-24 June 2005, Seattle, Washington, USA. Occasional Paper of the IUCN Species Survival Commission 32. IUCN, Gland (Switzerland) and Cambridge (UK).

ACIA 2005. Arctic Climate Impact Assessment: Scientific Report. Cambridge University Press. See their graphics package of sea ice projections here.

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.

Crockford, S.J. 2019The Polar Bear Catastrophe That Never Happened. Global Warming Policy Foundation, London. Available in paperback and ebook formats.

Crockford, S.J. 2020. State of the Polar Bear Report 2019. Global Warming Policy Foundation Report 39, London. pdf here.

Crockford, S.J. 2021. The State of the Polar Bear Report 2020. Global Warming Policy Foundation Report 48, London. pdf here.

Crockford, S.J. and Geist, V. 2018. Conservation Fiasco. Range Magazine, Winter 2017/2018, pg. 26-27. Pdf here.

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. Supplementary data here.

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 [accessed Nov. 28, 2015]. See the supplement for population figures.

via Watts Up With That?

May 14, 2021